Using Cisco CMTS Software

The Cisco universal broadband routers allow high-speed data services to be packaged similar to cable TV service or video fare. Cisco CMTS equipment supports data and digitized voice connectivity between Internet Protocol (IP) hosts and connected subscribers using a bidirectional cable TV and IP backbone.

Note For 6 MHz National Television Systems Committee (NTSC) cable plants that have not been fully upgraded to two-way transmission, the equipment works with dial-up access products to support upstream traffic from Data Over Cable Service Interface Specification (DOCSIS)-based telco-return cable modems.

For international cable plants that use 8-MHz Phase Alternating Line (PAL) or Systeme Electronique Couleur Avec Memoire (SECAM) channel plans, Cisco CMTS equipment supports bidirectional transfer of traffic between the Cable Modem Termination System (CMTS) and EuroDOCSIS-based CMs or set top box (STB) units with integrated EuroDOCSIS modems.

Cable companies and Internet service providers (ISPs) can allocate radio frequency (RF) channel capacity for Internet access, Virtual Private Network (VPN), or Voice over IP (VoIP) services using a hybrid fiber/coax (HFC) or all-coax cable plant. Cisco currently provides three router-based DOCSIS CMTS solutions that offer a wider feature set and better manageability than bridge-based systems:

Cisco uBR7223—Supports small-to-medium cable installations; the chassis contains one single-width IP backbone interface and up to two cable TV RF interfaces.
Cisco uBR7246—Supports large cable installations; the chassis contains up to two single-width IP backbone interfaces, up to four cable TV RF interfaces, and up to two power supplies.
Cisco uBR7246 VXR—Supports higher density and broad media configurations; the chassis contains up to two single-width IP backbone interfaces, up to four cable TV RF interfaces, up to two power supplies, an optional clock interface that enables the router to synchronize to an external timing reference, a faster processor, and higher bus bandwidth.

Note This guide focuses on Cisco CMTS software. For detailed descriptions of the Cisco CMTS chassis and components, refer to the Hardware Installation Guide for your CMTS and to the appropriate field replaceable unit (FRU) documents.

Cisco cable modem cards serve as the RF cable TV interfaces, supporting downstream and upstream signal combining and splitting arrangements. The cards require external upconverters to connect to the cable system. Cisco port adapters connect to the IP backbone and external networks. Your cable plant, combined with your planned and installed subscriber base, service offering, and external network connections, determine which Cisco CMTS chassis, cable modem cards, port adapters, and other components you use.

Data is modulated or demodulated using either:

Downstream 6 MHz channels in the 54-to-860 MHz range with upstream ranges of 5 to 42 MHz. Cisco MC11 FPGA, MC11C, MC12C, MC14C, MC16B, MC16C, and MC16S cable modem cards support NTSC channel operation, using standard (STD), Harmonic Related Carrier (HRC), or Incremental Related Carrier (IRC) frequency plans conforming to EIA-S542.

: NTSC uses a 6 MHz-wide modulated signal with an interlaced format of 25 frames per second and 525 lines per frame. NTSC is compatible with CCIR Standard M. PAL, used in West Germany, England, Holland, Australia, and several other countries.

Note Cisco 6 MHz products can be used in 8 MHz cable plants. The products, however, operate at a maximum downstream bandwidth of 27 Mbps, ignoring 2 MHz of available channel width, and limiting upstream channel choices to the range below 42 MHz.

Downstream 8 MHz channels in the 85-to-860 MHz range with an upstream range of 5 to 65 MHz. The Cisco MC16E cable modem card supports PAL and SECAM channel plans using an 8 MHz modulated signal.

: PAL uses a 625-line scan picture delivered at 25 frames per second where the color carrier phase definition changes in alternate scan lines. SECAM uses an 819 line scan picture that provides better resolution than PAL's 625-line and NTSC's 525-line.
: The MC16E uses the EuroDOCSIS J.112 (Annex A) standard, CableLabs ECR RFI-R-98036, which is similar to the Digital Audio Video Council/Digital Video Broadcast (DAVIC/DVB) ITU J.83 Annex A physical layer. Cable companies can support data, voice, and video services with DOCSIS-based CMs or set top boxes (STBs) that contain integrated EuroDOCSIS modems.

Caution The MC16E supports only Annex A operation and should not be used in production cable plants that support a 6 MHz channel plan.

Note The difference between DOCSIS and EuroDOCSIS is at the physical layer. EuroDOCSIS support requires the Cisco MC16E cable modem card, appropriate upconverters that support an 8 MHz PAL or SECAM channel plan, appropriate diplex filters, and EuroDOCSIS-based CMs or STBs.

The DOCSIS Radio Frequency (RF) specification defines the RF communication paths between the CMTS and CMs (or CMs in STBs). The DOCSIS RF specification defines the physical, link, and network layer aspects of the communication interfaces. It includes specifications for power level, frequency, modulation, coding, multiplexing, and contention control. Cisco offers products that support all DOCSIS error correction encoding and modulation types and formats, and that support DOCSIS Annex B or EuroDOCSIS Annex A operations.

DOCSIS NTSC Cable Plants

DOCSIS-compliant cable plants that support North American channel plans use ITU J.83 Annex B RF. Figure 1-1 illustrates a DOCSIS two-way and telco-return architecture.

Figure 1-1: DOCSIS Two-Way and Telco-Return Architecture

Larger cable companies typically have high-speed fiber backbones that carry Internet data, voice, and video between the following cable company facilities:

Regional processing centers
Headends
Hubs

The fiber backbone can be made up of OC-3 (155 Mbps) to OC-48 (2488 Mbps) Synchronous Optical Network (SONET) or Asynchronous Transfer Mode (ATM) rings. The backbone network can connect to other networks, including the Public Switched Telephone Network (PSTN), other cable system backbones, or to public Internet interconnect points that multiple ISPs use.

The CMTS Media Access Control (MAC) domain typically includes one or more downstream paths and one or more upstream paths. Depending on the CMTS configuration, the CMTS MAC domain can be defined to have its downstreams on one cable modem card with its upstreams on another card, or one or more CMTS MAC domains per cable modem card.

Cisco provides high-speed routers to route interactive traffic between the backbone and Ethernet in the headend internal network. Signaling protocols maintain the network intelligence needed to route traffic optimally, automatically building and maintaining routing tables to direct traffic and signal failures for rerouting in the network.

Border Gateway Protocol (BPG) typically operates between the cable operator's regional network and external networks, providing routing information exchange between different networks. The Open Shortest Path First (OSPF) protocol is used in regional networks usually. Cisco routers incorporate Cisco IOS software, which offers advanced software features, including quality of service (QoS), Weighted Fair Queuing (WFQ), and IP multicast.

EuroDOCSIS Cable Plants

EuroDOCSIS-based cable plants use EuroDOCSIS J.112 (Annex A) standard, similar to the DAVIC/DVB J.83 Annex A physical layer. The MC16E builds on the DOCSIS protocol, adding support at the physical layer for PAL and SECAM channel plans. The card permits full bandwidth utilization of the 8 MHz downstream channel, allowing up to 50 Mbps throughput, and greater upstream frequency selection—5 to 65 MHz, instead of 5 to 42 MHz.

Figure 1-2 illustrates a three-tier EuroDOCSIS configuration involving STB deployment. The sample architecture has four subsystems:

High-speed fiber backbone—Carries Internet data, voice, and video between regional processing centers, headends, and hubs.
Headend—Aggregates content at the national and regional level and sends it to the fiber backbone.
Hub—Combines regional programming with local content and sends that combined content to the cable network.
Interactive STBs with integrated EuroDOCSIS CMs—Connects subscribers to the cable network.

Video sources are Motion Picture Experts Group (MPEG) encoded and then fed into an MPEG multiplexer that packs the MPEG video streams into a single stream. This stream is uplinked to a satellite and then downlinked to multiple headends, which then distribute the MPEG stream directly onto the HFC plant.

The STB receives signals from the cable network and displays them on a television. An STB with EuroDOCSIS CM functionality supports two-way interactivity. Inside the EuroDOCSIS STB are two tuners:

One handles MPEG-2 video, audio, broadcast control data, and broadcast service data.
The other supports DOCSIS IP data. The return path is implemented with EuroDOCSIS.

Figure 1-2: EuroDOCSIS and STB Architectur
e

Downstream Signals

Downstream signals are modulated using 64 or 256 Quadrature Amplitude Modulation (QAM), based on the cable modem card used, your cable plant, and the significance of the data. DOCSIS defines the messages and data types for CMTS to CM (or CM in an STB) communications. All CMs listen to all frames transmitted on the downstream channel on which they are registered and accept those where the destinations match the units themselves or the devices each supports.

The Cisco CMTS supports multicast groups using standard protocols such as Protocol Independent Multicast (PIM), Distance Vector Multicast Routing Protocol (DVMRP), and Internet Group Management Protocol (IGMP) to determine if multicast streams are to be forwarded to a prescribed downstream CM or STB, or a multicast routing peer.

The Cisco CMTS software periodically sends MAC allocation and management messages—known as MAPs—to all CMs on the network, defining the transmission availability of channels for specific periods of time. The MAP rate is fixed—every 2 msec.

Different transmission intervals are defined that associate an interval with a Service Identifier (SID). SIDs define the devices allowed to transmit and provide device identification and class of service management. Software defines what type of transmission is allowed during the interval.

The CMTS system administrator typically assigns one or more SIDs to each CM, corresponding to the classes of service the CM requires. Each MAP is associated with a particular upstream channel. The SID concept supports multiple data flows and use of protocols such as Resource Reservation Protocol (RSVP) that allows IP backbone QoS features to be extended to the CMTS. The CMTS schedules the times granted for sending and receiving packets, and if defined, manipulates the type of service (ToS) field in the IP packet header to accommodate QoS.

Note Cisco CMTS software supports extensions to DOCSIS 1.0 to operate with DOCSIS 1.0-based CMs or cable RF CPE devices (such as Cisco uBR924 cable access routers or Cisco uBR910 series cable data service units) that also support DOCSIS 1.0 extensions.

Tips DOCSIS 1.0 extensions address the problem of QoS for VoIP until DOCSIS 1.1 is solidified. Currently, only certain vendors offer products that support DOCSIS 1.0 extensions.

DOCSIS 1.0 extensions build intelligence into the MAP file the CMTS sends to voice-enabled CMs to address jitter and delay. The extensions support unsolicited grants, allowing a portion of bandwidth to be dedicated to a voice call as soon as a subscriber initiates a call until that call is terminated. Unsolicited grants are used to create a constant bit rate-like stream between the CMTS and the CM, in contrast to typical data applications where CMs request grants from the CMTS before they can transmit upstream. Refer to the "Cisco IOS Releases and Software/Hardware Matrix Tables" section for specific release feature sets.

Upstream Signals

The upstream channel is characterized by many CMs (or CMs in STBs) transmitting to the CMTS. These signals typically operate in a burst mode of transmission. Time in the upstream channel is slotted.

The CMTS provides time slots and controls the usage for each upstream interval. The CMTS sends regular mappings of minislot structure in downstream broadcast MAP messages. The CMTS allocates contention broadcast slots that all CMs can use, and also allocates upstream minislots for unicast or non-contention data from specific CMs.

The CMTS allocates two basic types of contention slots on the upstream:

Initial ranging slots that CMs use during their initialization phase to join the network. Once the CMTS receives an initial ranging request from a CM using this kind of slot, it subsequently polls the CM, along with other operational CMs, in unicast, non-contention station maintenance slots. Refer to the"Subscriber Management" section for CM provisioning and initialization processes.
Bandwidth-request minislots that CMs use to request data grants from the CMTS to send data upstream in non-contention mode. Any CM can use this type of minislot to request a data grant from the CMTS.

The stream of initial ranging slots and bandwidth request minislots comprise two separate contention subchannels on the upstream. Cisco CMTS software uses a "dynamic bandwidth-request minislots-per-MAP" algorithm to dynamically control the rate of contention slots for initial ranging and bandwidth-requests. The CMTS uses a common algorithm to vary backoff parameters that CMs use within each of the two upstream contention subchannels. The CMTS uses these algorithms to dynamically determine the initial ranging slots and bandwidth-request minislots to allocate on the slotted upstream.

When power is restored after a catastrophic power failure, a large number of CMs will want to join the network simultaneously. This represents an impulse load on the initial ranging subchannel. The CMTS in this situation will increase the frequency of initial ranging slots so that CMs can quickly join the network.

During high upstream data loads, the CMTS conserves the scarce upstream channel bandwidth resource and is more frugal in introducing upstream initial ranging slots. The CMTS schedules bandwidth-request minislots at low loads to provide low access delay. At high upstream loads, the CMTS reduces the number of contention-based request minislots in favor of data grants, while maintaining a minimum number of request slots.

Note The system default is to have the automatic dynamic ranging interval algorithm enabled, automatic dynamic ranging backoff enabled, and data backoffs for each upstream on a cable interface. Commands to configure the dynamic contention algorithms include:
[no] cable insertion-interval [automatic [<Imin [Imax]>] in msecs
[no] cable upstream <port number> range backoff [automatic] | [<start> <end>]
[no] cable upstream <port number> data-backoff [automatic] | [<start> <end>]

Caution In general, Cisco discourages adjusting default settings. Only personnel who have received the necessary training should attempt to adjust values.

The Cisco CMTS equipment periodically broadcasts Upstream Channel Descriptor (UCD) messages to all CMs. These messages define upstream channel characteristics that include upstream frequencies, symbol rates and modulation schemes, Forward Error Correction (FEC) parameters, and other physical layer values.

Upstream signals are demodulated using Quadrature Phase Shift Keying (QPSK) or Quadrature Amplitude Modulation (QAM). QPSK carries information in the phase of the signal carrier, whereas QAM uses both phase and amplitude to carry information.

Tips If your cable plant is susceptible to ingress or noise, QPSK is recommended based on the importance of the data. Frequencies below 20 MHz are more susceptible to noise and might require lower symbol rates. Higher frequencies might be able to support higher rates and use QAM modulation instead.

Feature Set Highlights

Currently, the Cisco universal broadband routers feature:

Interoperability with DOCSIS-based two-way or telco-return CMs, EuroDOCSIS CMs or STBs with integrated EuroDOCSIS CMs when using Cisco MC16E cable modem cards, Cisco cable access routers such as the Cisco uBR924 or Cisco uBR904, or Cisco uBR910 series cable data service units (DSUs).
Security using DOCSIS baseline privacy interface (BPI) or options for managed CPE such as authentication, authorization, and accounting (AAA) servers and routers. The system supports access control lists (ACLs), tunnels, filtering, protection against spoofing, and commands to configure source IP filtering on RF subnets to prevent subscribers from using source IP addresses not valid for the IP subnets to which they are connected.
QoS support, allowing traffic classes and service levels to be defined to efficiently map data packets into traffic classes that determine how network resources are allocated and controlled. QoS can be delivered through a combined use of IP precedence ToS bits and QoS capabilities of IP and ATM core networks.
Cisco CMTS software supports DOCSIS 1.0 QoS, which includes:
- Service priority of 7 to 0; a higher value indicates better service
- Maximum allowed upstream rate in bps
- Maximum upstream channel burst in minislots
- Minimum reserved upstream rate in bps
- Maximum allowed downstream rate in bps
Cisco CMTS software supports varying QoS definitions for differentiated services:
- A guaranteed-rate service queue to store bandwidth requests from CMs subscribing to a class with minimum upstream rate on the upstream channel
- A best effort service queue to store bandwidth requests from CMs subscribing to a class with no minimum upstream rate on the upstream channel
DOCSIS 1.0 QoS extensions which include:
- Multi-SID support that allows the definition of multiple SIDs on the upstream for multiple service classes per CM: voice traffic can be designated on a higher QoS committed information rate (CIR) secondary SID, while data traffic can be forwarded on a best effort basis on a primary SID. Secondary SIDs are higher QoS CIR-type classes. These classes have a non-zero minimum reserved rate (CIR-type service). That way, these SIDs receive preferential treatment at the CMTS for grants over any tiered best effort type data SID of that upstream. Best effort service involves requests with no minimum upstream rate on the channel. The CMTS treats the primary and secondary SIDs independently for issuing grants. Each SID of a CM has an independent state machine. Channel access for each SID is independent of the other SID.

Tips Reliable operation with voice requires multiple SIDs—at least two per cable modem to separate voice from data traffic. In DOCSIS 1.0, SIDs are set up statically. When supporting DOCSIS 1.0 extensions, SIDs can be set up statically or dynamically. The CMTS and CM must support this capability.

Note Revisions of Cisco CMTS software support varying DOCSIS 1.0 extensions. Refer to the "New Cisco IOS EC Release Train" section.

CM-initiated dynamic MAC messages—Dynamic Service Addition (DSA) and Dynamic Service Deletion (DSD). These messages allow dynamic SIDs to be created and deleted at run-time on a per VoIP call basis.
Unsolicited grant service (CBR-scheduling) on the upstream—This helps provide a higher quality channel for upstream VoIP packets from an Integrated Telephony Cable Modem (ITCM) such as the Cisco uBR924 cable access router.
Ability to provide separate downstream rates for any given ITCM, based on the IP-precedence value in the packet. This helps separate voice signaling and data traffic that goes to the same ITCM to address rate shaping purposes.

Caution All DOCSIS 1.0 extensions are activated only when a CM or Cisco uBR924 that supports these extensions solicits services via dynamic MAC messages. If the CMs in your network are all DOCSIS 1.0-based, they will receive regular DOCSIS 1.0 treatment from the CMTS.

Concatenation—To increase the per-CM upstream throughput in certain releases of software, Cisco CMTS software supports a concatenated burst of multiple MAC frames from a CM that supports concatenation.

Tips Concatenation is supported only with CMs that support DOCSIS concatenation as part of DOCSIS 1.0 extensions. The results of the show controller command indicate whether concatenation is enabled on an interface.

Concatenation is enabled by default for current cable modem cards, but can be disabled with the Cisco IOS no cable upstream number concatenation interface command. A CM that concatenates after the Cisco IOS no cable upstream number concatenation interface command is issued is considered noncompliant.

Rate limiting per DOCSIS-1.0-99, which limits the data rate to and from a CM; the MAC scheduler supports traffic-shaping capabilities for downstream and upstream traffic. Rate limiting ensures no single CM consumes all of the channel bandwidth and also allows a CMTS administrator to configure different maximum data rates for different subscribers. Subscribers requiring higher peak rates and willing to pay for this can be configured with higher peak rate limits in their CM DOCSIS configuration file over regular subscribers who pay less and get lower rate limits.

Each time a packet belonging to a flow is transmitted on an output channel, the token bucket policer function checks the rate limit status of the flow, passing the following parameters:

Token bucket peak rate in bits/msec
Token bucket depth (maximum transmit burst) in bits
Length of current packet to be sent in bits
Pointer to the flow's token bucket
Pointer to the flow's token bucket last update timestamp
Variable to return the msec buffering delay in case the packet needs to be shaped
Maximum buffering delay that the subsequent traffic shaper can handle in msecs

Every flow has its own shaping buffer where rate-exceeded packets are typically held back in first-in/first-out (FIFO) order for later transmission

Traffic shaping (relates to rate limiting)—a Cisco patent-pending feature that reduces the chance that information must be retransmitted to hosts on the cable plant. When rate limiting CMs on the network, the Cisco CMTS software typically drops packets to enforce the rate limit. Dropping packets from the requesting CM causes the host sending the information to retransmit its information. Retransmitted information wastes bandwidth on the network. If both the hosts sending and requesting information are on the cable plant, the upstream bandwidth is wasted as well.

The traffic shaping feature delays the scheduling of the upstream packet, which in turn causes the packet to be buffered on the cable CPE device, instead of being dropped. This allows the user's Transmission Control Protocol/Internet Protocol (TCP/IP) stack to pace the application traffic appropriately and approach throughput commensurate with the subscriber's defined QoS levels.

The Cisco CMTS supports the following traffic shaping features:

Downstream rate shaping to include ToS—Allows traffic shaping from the CMTS on a DOCSIS downstream channel. The feature allows administrators to configure the ToS byte to calculate the data rate for a specified flow. You can override the common maximum downstream data rate.

Tips Packets that contain ToS bytes that have not been configured for downstream data rates continue to use the common data rate limits. ToS is supported using Cisco IOS Release 12.0(5)T1 or higher CMTS images.

Upstream rate shaping—Allows upstream rate shaping from the CMTS on a DOCSIS upstream channel. Upstream grant shaping is per CM (SID). The grant shaping feature is a configurable option for the current upstream token-bucket rate limiting algorithm.

Tips Token bucket policing with shaping is the new per-upstream default rate limiting setting at the CMTS. Shaping can be enabled or disabled for the token-bucket algorithm. An extra keyword "shaping" has been added at the end of the token bucket rate limiting algorithm configuration command using Cisco IOS Release 12.0(5)T1 CMTS images.

Restricted QoS class assignment—This feature allows a CMTS administrator to override the class of service provisioned for a CM. When this feature is enabled, the user-defined QoS profile is enforced on the CM attempting to register with the CMTS, regardless of the provisioned class of service.

Tips This feature is added to address instances where a cable operator implemented rate-limiting incorrectly. The feature allows an administrator to override the statically-provisioned QoS parameters of the CM and force the CM to use a specific QoS profile defined at the CMTS.

Note By default, the system will not enforce any specific QoS profile on the CM. The QoS profile assigned to the CM will depend on the class of service parameters provisioned in the CM's DOCSIS configuration file.

Spectrum management capabilities to ensure data is delivered reliably over the cable plant. The system supports the creation of up to 32 cable spectrum groups, allowing multiple upstream ports in a single spectrum group, and specifications of configured channel-widths for upstream segments. Upstream frequencies can be assigned as follows:
- Fixed
- Single subband—the CMTS administrator can define a center frequency and symbol rate such that the boundaries of the upstream carrier stay within the subband. The frequency and symbol rate can change within the boundary in response to noisy line conditions, based on the defined upstream parameters.
- Multiple subbands; the data carrier can remain in a particular subband for a duration of time and then hop to another subband based on the defined upstream parameters.

Note The above fequency agility specifications are based on predetermined sets of frequencies which might or might not have adequate C/N ratio at any given time.

Dynamically assigned using the MC16S cable modem card and hardware-based spectrum management enhancements; the CMTS administrator can define an acceptable threshold for the number of lost station messages from a CM that causes a frequency hop to a channel with adequate C/N. Cisco CMTS software initiates a frequency hop to another channel when the pre-defined threshold for the number of lost station messages is met, based on the upstream spectrum data the MC16S collects. Cisco CMTS software scans the upstream spectrum for clean, usable channels for the specified 3.2 MHz, 1.6 MHz, 800 kHz, 400 kHz, and 200 kHz channel width. If no acceptable channels per the specified width are found, the Cisco MC16S cable modem card scans the upstream spectrum for the next largest available channel width.

Caution Upstream modulation profiles can be assigned to specific CMs based on the Cisco cable modem card used—mainly "C" cable modem cards, as well as the MC16S. Only those familiar with DOCSIS who have received the proper training should create upstream modulation profiles.

Note The Cisco MC16S cable modem card supports only 6 MHz NTSC cable plant operations. No other cable modem card, but the MC16S, offers software and hardware spectrum management enhancements that allow an administrator to define an acceptable threshold for the number of lost station messages from a CM that will cause a frequency hop to a channel with adequate C/N based on defined parameters.

Debugging commands to diagnose problems with:
- CMs and the cable plant—Cisco CMTS series software includes a Cisco-patented flap list command that helps isolate problems between the cable plant (such as ingress noise or incorrect power levels) or specific CMs. A flap is defined as a CM being registered on the CMTS, deregistering, and then immediately reregistering. With the flap list, you can quickly learn how to characterize trouble patterns in the network, determine which amplifier or feeder line is faulty, distinguish an upstream from downstream path problem, and isolate an ingress noise impairment from a plant equipment problem.
- TCP/IP and provisioning problems—the system supports tracing and debugging DHCP related messages on an administrator-specified CMTS network interface, tracing and debugging all MAC-layer DOCSIS messages for an administrator-defined MAC address, as well as other debugging commands to monitor specific processes.
Dynamic ranging; the dynamic ranging feature is a Cisco patent-pending feature that supports quick restoration of service following a catastrophic plant failure. With dynamic ranging, hundreds of cable modems can come back online quickly because the time that cable modems spend deferring contention ranging slots is minimized. This reduces cable modem reinitialization time.

This results from use of Cisco CMTS algorithms that vary the number of contention bandwidth-request minislots and request slots. Software converts unallocated minislots in the current MAP into request minislots as needed. At low upstream loads, most of the MAPs of that upstream have no grants to serve and the scheduler converts all unallocated (ungranted) minislots into request minislots. This helps in ensuring a low access delay for CMs at low loads due to the abundance of request opportunities. At high upstream loads, the scheduler has data grants to be served before allocating the next request region and will automatically reduce the number of request minislots.

The initial ranging slots—also called initial maintenance slots—are each about 2 msecs wide. These slots are used by CMs joining the cable network, and thus, are subject to ranging collisions. CMs use these slots for initial connectivity with the CMTS only. Once the initial ranging message from the CM is received successfully, the CM no longer uses such contention ranging slots for subsequent operations.

The CMTS periodically polls CMs with unicast station maintenance slots. Any action that involves a simultaneous bringing up of many CMs on an upstream channel—service restoration after a catastrophic power failure, online insertion and removal (OIR) for CMTS cable modem cards, or fiber node servicing—gives rise to an impulse ranging contention state on each of the affected upstream channels. Rebooted CMs on the upstream attempt to send initial ranging MAC messages using broadcast initial ranging slots at roughly the same time. Without the Cisco CMTS algorithms enabled, CMs can repeatedly collide and back-off a random number of initial ranging slots independently before trying again.

With Cisco CMTS algorithms enabled, the CMTS can detect such high contention scenarios and can increase the frequency of initial ranging slots to assist in quick resolution of ranging contention. After the high collision state is over—few persistent ranging collisions on the upstream—the CMTS detects this condition and switches back to the steady state mode. In the steady state mode, the frequency of initial ranging slots is a function of the upstream channel utilization. If extra upstream bandwidth is available, the CMTS allocates more initial upstream ranging slots. As soon as the MAC scheduler needs the upstream bandwidth for data grants, it reduces the frequency of initial ranging slots.
Downstream channel ID configuration: This feature allows system administrators to enter a configurable downstream channel ID to a value other than the default of "1." The change enables each downstream channel ID to be unique on a cable network.

Note CMs communicate their downstream ID when making a connection, and not the downstream frequency.

Tips This feature might be used in instances where an MSO wants to send multiple downstream frequencies of DOCSIS to a single region, but the CMs have only the capability to connect the return path to upstream ports on one cable modem card. In this instance, you can use the cable down channel-id number command to assign a unique channel ID for each downstream that a CM is capable of receiving. The downstream frequency setting, however, must match the setting on the upconverter.

Clock synchronization for voice applications when using the Cisco uBR7246 VXR and clock card hardware and software; this combination supports increased reliability for VoIP transmissions to synchronize:
- Vocoders with a clock source
- Data transmissions between end-points

Refer to "Cisco IOS Releases and Software/Hardware Matrix Tables" section for software releases that support various features.

Hot Standby 1+1 Redundancy: This feature provides high system availability when you configure a Cisco CMTS to wait in "hot-standby" mode, protecting another Cisco CMTS in the event of a system failure.
Dynamic Upstream Modulation: This feature provides improved performance using proactive spectrum management functions.
Cable Monitor: This feature provides upstream and downstream sniffer capabilities.
Cable Interface Setup Facility: This feature provides an automated configuration for your CMTS.
Overlapping Subinterface IP Addresses: This feature allows you to reuse IP addresses by supporting multiple IP address spaces (groups) and allowing the verification of non overlapping IP address pools within a pool group. Pools without an explicit group name are considered members of the base system group and are processed in the same manner as the original IP pool implementation.
SNMP Cable Modem Remote Query: This feature provides a new MIB, CISCO-DOCS-REMOTE-QUERY-MIB, which, when implemented on a CMTS, facilitates SNMP polling of remote CMs. This MIB includes the configuration of the CMTS CM Poller, as well as status objects of remote CMs that are polled by the CMTS CM Poller.

: A new CLI command has been implemented for turning on the trap:

snmp-server enable cable cm-remote-query

Subscriber Management

CMs are assigned to operate on specific cable channels to balance activity across several channels. Each Cisco CMTS cable modem card serves a specific downstream channel and upstream segment. Part of network planning is to define the channels to use.

In typical cable networks, administrators limit the configuration responsibilities of field service technicians and the amount of information collected on subscriber CPE devices. Field service technicians are sent to subscriber homes or businesses to install the CM or STB and ensure all computing devices are DHCP-enabled.

The CMTS administrator defines and pushes DHCP and DOCSIS configuration files to appropriate servers such that each CM or CM in an STB on the network, when initialized, can transmit a DHCP request, receive its IP address, obtain its TFTP and TOD server addresses, and download its DOCSIS configuration file (or updated Cisco IOS CM image if using a Cisco uBR924, Cisco uBR910 series DSU, or Cisco uBR904).

DOCSIS 1.0-based CMs cannot connect to the broadband network until the following occurs:

Step 1 The CM initializes and ranges through available frequencies until it finds the first frequency that it can use to communicate to the CMTS—known as scanning for a downstream channel.

Step 2 The CM obtains upstream parameters and performs ranging.

Step 3 The CM goes through the DHCP server process and establishes IP connectivity, time of day (TOD), and security (optional). At this point, the CM cannot determine if it is communicating on the correct channel.

Step 4 The CM receives a DOCSIS configuration file from the Trivial File Transfer Protocol (TFTP) server. One of the parameters in the DOCSIS configuration file tells the CM which channel it can use.

Step 5 The CM registers with the CMTS.

Step 6 If the network supports DOCSIS baseline privacy interface (BPI) or other secure data sets, encryption/decryption processes are initialized.

Step 7 The CM is ready for normal operations. Once initialized and operational, CMs send requests to initiate data transmission to the CMTS.

The CMTS system administrator or customer service representative ensures appropriate databases are updated to activate and support the new subscriber account in the provisioning, billing, or network management systems in use for the network. Each CM or STB serial number and MAC address is typically stored in the billing and administrative system.

Initial and station maintenance management messages are sent to maintain communications between CMs and the CMTS. CM reinitialization is illustrated below:

6d17h:580447.276 CMAC_LOG_DRIVER_INIT_IDB_RESET              0x080A2400
6d17h:580447.280 CMAC_LOG_LINK_DOWN                          
6d17h:580447.282 CMAC_LOG_RESET_FROM_DRIVER                  
6d17h:580447.284 CMAC_LOG_STATE_CHANGE
wait_for_link_up_state
6d17h:580447.286 CMAC_LOG_LINK_UP                            
6d17h:580447.290 CMAC_LOG_STATE_CHANGE
ds_channel_scanning_state
6d17h:580447.416 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
81/453000000/855000000/6000000
6d17h:580447.420 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
82/93000000/105000000/6000000
6d17h:580447.424 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
83/111025000/117025000/6000000
6d17h:580447.428 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
84/231012500/327012500/6000000
6d17h:580447.432 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
85/333025000/333025000/6000000
6d17h:580447.436 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
86/339012500/399012500/6000000
6d17h:580447.440 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
87/405000000/447000000/6000000
6d17h:580447.444 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
88/123012500/129012500/6000000
6d17h:580447.448 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
89/135012500/135012500/6000000
6d17h:580447.450 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
90/141000000/171000000/6000000
6d17h:580447.454 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
91/219000000/225000000/6000000
6d17h:580447.458 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
92/177000000/213000000/6000000
6d17h:580447.462 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
93/55752700/67753300/6000300
6d17h:580447.466 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
94/79753900/85754200/6000300
6d17h:580447.470 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
95/175758700/211760500/6000300
6d17h:580447.474 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
96/121756000/169758400/6000300
6d17h:580447.478 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
97/217760800/397769800/6000300
6d17h:580447.482 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
98/73753600/115755700/6000300
6d17h:580447.486 CMAC_LOG_WILL_SEARCH_DS_FREQUENCY_BAND
99/403770100/997799800/6000300
6d17h:580447.490 CMAC_LOG_WILL_SEARCH_SAVED_DS_FREQUENCY     501000000
6d17h:580447.492 CMAC_LOG_WILL_SEARCH_SAVED_DS_FREQUENCY     555000000
6d17h:%LINEPROTO-5-UPDOWN:Line protocol on Interface cable-modem0,
changed state to down
6d17h:580448.496 CMAC_LOG_UCD_MSG_RCVD                       1
6d17h:580448.500 CMAC_LOG_UCD_MSG_RCVD                       2
6d17h:580448.502 CMAC_LOG_UCD_MSG_RCVD                       3
6d17h:580448.504 CMAC_LOG_UCD_MSG_RCVD                       4
6d17h:580449.812 CMAC_LOG_DS_64QAM_LOCK_ACQUIRED             555000000
6d17h:580449.814 CMAC_LOG_DS_CHANNEL_SCAN_COMPLETED          
6d17h:580449.816 CMAC_LOG_STATE_CHANGE
wait_ucd_state
6d17h:580450.510 CMAC_LOG_UCD_MSG_RCVD                       1
6d17h:580450.512 CMAC_LOG_UCD_MSG_RCVD                       2
6d17h:580450.514 CMAC_LOG_UCD_MSG_RCVD                       3
6d17h:580450.518 CMAC_LOG_UCD_MSG_RCVD                       4
6d17h:580452.524 CMAC_LOG_UCD_MSG_RCVD                       1
6d17h:580452.528 CMAC_LOG_ALL_UCDS_FOUND                     
6d17h:580452.530 CMAC_LOG_STATE_CHANGE
wait_map_state
6d17h:580452.534 CMAC_LOG_UCD_NEW_US_FREQUENCY               19984000
6d17h:580452.536 CMAC_LOG_SLOT_SIZE_CHANGED                  8
6d17h:580452.616 CMAC_LOG_FOUND_US_CHANNEL                   4
6d17h:580452.618 CMAC_LOG_UCD_MSG_RCVD                       2
6d17h:580452.620 CMAC_LOG_UCD_MSG_RCVD                       3
6d17h:580452.624 CMAC_LOG_UCD_MSG_RCVD                       4
6d17h:580452.630 CMAC_LOG_MAP_MSG_RCVD                       
6d17h:580452.632 CMAC_LOG_INITIAL_RANGING_MINISLOTS          40
6d17h:580452.634 CMAC_LOG_STATE_CHANGE
ranging_1_state
6d17h:580452.636 CMAC_LOG_RANGING_OFFSET_SET_TO              9610
6d17h:580452.640 CMAC_LOG_POWER_LEVEL_IS                     28.0  dBmV
(commanded)
6d17h:580452.642 CMAC_LOG_STARTING_RANGING                   
6d17h:580452.644 CMAC_LOG_RANGING_BACKOFF_SET                0
6d17h:580452.648 CMAC_LOG_RNG_REQ_QUEUED                     0
6d17h:580452.690 CMAC_LOG_RNG_REQ_TRANSMITTED                
6d17h:580452.694 CMAC_LOG_RNG_RSP_MSG_RCVD                   
6d17h:580452.698 CMAC_LOG_RNG_RSP_SID_ASSIGNED               6
6d17h:580452.700 CMAC_LOG_ADJUST_RANGING_OFFSET              2291
6d17h:580452.702 CMAC_LOG_RANGING_OFFSET_SET_TO              11901
6d17h:580452.704 CMAC_LOG_ADJUST_TX_POWER                    9
6d17h:580452.706 CMAC_LOG_POWER_LEVEL_IS                     30.0  dBmV
(commanded)
6d17h:580452.710 CMAC_LOG_STATE_CHANGE
ranging_2_state
6d17h:580452.714 CMAC_LOG_RNG_REQ_QUEUED                     6
6d17h:580453.600 CMAC_LOG_RNG_REQ_TRANSMITTED                
6d17h:580453.604 CMAC_LOG_RNG_RSP_MSG_RCVD                   
6d17h:580453.606 CMAC_LOG_RANGING_SUCCESS                    
6d17h:580453.608 CMAC_LOG_STATE_CHANGE                       dhcp_state
6d17h:580453.742 CMAC_LOG_DHCP_ASSIGNED_IP_ADDRESS           5.108.1.3
6d17h:580453.744 CMAC_LOG_DHCP_TFTP_SERVER_ADDRESS           128.1.1.2
6d17h:580453.746 CMAC_LOG_DHCP_TOD_SERVER_ADDRESS            128.1.1.2
6d17h:580453.750 CMAC_LOG_DHCP_SET_GATEWAY_ADDRESS           
6d17h:580453.752 CMAC_LOG_DHCP_TZ_OFFSET                     28800
6d17h:580453.754 CMAC_LOG_DHCP_CONFIG_FILE_NAME              gold.cm
6d17h:580453.756 CMAC_LOG_DHCP_ERROR_ACQUIRING_SEC_SVR_ADDR  
6d17h:580453.760 CMAC_LOG_DHCP_COMPLETE                      
6d17h:580453.884 CMAC_LOG_STATE_CHANGE
establish_tod_state
6d17h:580453.890 CMAC_LOG_TOD_REQUEST_SENT                   
6d17h:580453.904 CMAC_LOG_TOD_REPLY_RECEIVED                 3165851032
6d17h:580453.910 CMAC_LOG_TOD_COMPLETE                       
6d17h:580453.912 CMAC_LOG_STATE_CHANGE
security_association_state
6d17h:580453.916 CMAC_LOG_SECURITY_BYPASSED                  
6d17h:580453.918 CMAC_LOG_STATE_CHANGE
configuration_file_state
6d17h:580453.920 CMAC_LOG_LOADING_CONFIG_FILE                gold.cm
6d17h:%LINEPROTO-5-UPDOWN:Line protocol on Interface cable-modem0,
changed state to up
6d17h:580454.950 CMAC_LOG_CONFIG_FILE_PROCESS_COMPLETE       
6d17h:580454.952 CMAC_LOG_STATE_CHANGE
registration_state
6d17h:580454.956 CMAC_LOG_REG_REQ_MSG_QUEUED                 
6d17h:580454.960 CMAC_LOG_REG_REQ_TRANSMITTED                
6d17h:580454.964 CMAC_LOG_REG_RSP_MSG_RCVD                   
6d17h:580454.966 CMAC_LOG_COS_ASSIGNED_SID                   1/6
6d17h:580454.970 CMAC_LOG_RNG_REQ_QUEUED                     6
6d17h:580454.976 CMAC_LOG_REGISTRATION_OK                    
6d17h:580454.978 CMAC_LOG_STATE_CHANGE
establish_privacy_state
6d17h:580454.980 CMAC_LOG_PRIVACY_NOT_CONFIGURED             
6d17h:580454.982 CMAC_LOG_STATE_CHANGE
maintenance_state

Cisco CMTS Configuration Tools

Cisco Network Registrar (CNR)

Cisco provides a configuration tool with each Cisco CMTS—Cisco Network Registrar (CNR)—to automate dynamic IP address allocation to cable modems, PCs, and other devices on the broadband network. Using CNR, the amount of customer service involvement needed to track subscriber CPE equipment is reduced. You track serial numbers and MAC addresses for each cable modem on your network, but do not track information about PC or Network Interface Card (NIC) changes.

Cisco Subscriber Registration Center (CSRC)

For high-end systems, Cisco offers a complete suite of products—the Cisco Subscriber Registration Center (CSRC). CSRC consists of:

Cisco Network Registrar (CNR)—Domain name system (DNS) and DHCP server application.
Cisco Modem Registrar—Trivial File Transfer Protocol/time of day (TFTP/ToD) server application.
Cisco Access Registrar—Remote access dial-in user service (RADIUS) server application.
Cisco User Registrar—User interface that supports subscriber self-registration.

These applications help specify the contents of the DOCSIS TFTP or Cisco IOS configuration files. Based on password-authenticated identity, these applications control what configuration capabilities are available to subscribers.

The suite of applications not only support provisioning, but offer application programming interfaces (APIs) for business system integration. These APIs enable data and voice service provisioning systems to share common user and service information using a standards-based Lightweight Directory Access Protocol (LDAP) directory scheme.

DOCSIS CPE Configurator

Cisco also offers an HTML-based DOCSIS CPE Configurator tool that can be accessed from Cisco Connection Online (CCO). The tool is designed to collect information needed to generate a DOCSIS CM configuration file. The generated file is in binary format consistent with the DOCSIS RF Specification (SP-RFI-105-991105).

Server Requirements

Two-Way

A TFTP server, DHCP server, and ToD server are required to support DOCSIS 1.0-based CMs on the network. A DOCSIS 1.0-based CM will not boot if these servers are not available.

Log server and security servers are not required to configure and operate a CM. If the log server or security servers are not present, a CM will generate warning messages, but will continue to boot and function properly.

TOD and TFTP servers are standard Internet implementations of the RFC 868 and RFC 1350 specifications. Most computers running a UNIX-based operating system, supply TOD and TFTP servers as a standard software feature. Typically, the TOD server is embedded in the UNIX inetd and requires no additional configuration. The TFTP server is usually disabled in the standard software, but can be enabled by modifying the inetd.conf file. Microsoft NT server software includes a TFTP server that can be enabled with the services control panel. Microsoft NT does not include a TOD server. A public domain version of the TOD server for Microsoft NT can be downloaded from several sites.

Telco Return

A remote access server is required for networks that support telco return. In telco return configurations, upstream data from a PC through the CM to the Internet is carried over a dial-up connection. This dial-up connection can include a log or security server. Telco return cable modems can be set up to use the logging and security servers. This is accomplished by including the appropriate DHCP options in the cable modem policy as described in CNR or CSRC documentation and appropriate chapters of this guide.

EuroDOCSIS STB Support

Depending on the network configuration, servers that support Internet-enhanced video services—DTV application servers, user data servers, system management servers—and other tools and applications, are required to enable cable operators to deliver centrally managed services through STBs.

See the "Cisco Subscriber Registration Center (CSRC)" section. APIs need to be set up to allow EuroDOCSIS servers to communicate with the CSRC directory to obtain such information as IP addresses, user names, and subscription levels.

After registered subscribers receive a EuroDOCSIS-based STB, they can connect up the STB. Automatic configuration begins when the CM in the STB is detected and the CSRC DHCP server establishes IP connectivity and the basic IP configuration. As part of this initialization, the DHCP server transmits to the client STB, binding information for other resources such as TOD and TFTP servers. When using this initial configuration, the DOCSIS CM uses TFTP to download its default DOCSIS configuration file, such as the DOCSIS options associated with the STB vendor subnet and CMTS. When minimally configured, the STB will register with the Cisco CMTS and create an associated object in the LDAP directory. The subscriber can then access the Cisco User Register web user interface to select one or more of the service packages the cable operator offers.

Supported Services

Basic Internet Access Data

A Cisco CMTS and an intermediate frequency (IF)-to-RF upconverter are installed at the headend or distribution hub to transmit digital data. The Cisco CMTS downstream ports transmit IF signals to the upconverter, which translates the downstream signals to RF for broadcast.

Receivers, scramblers, and descramblers then process the TV signals to encode or decode signals as needed for broadcast. Modulators format the analog TV and digital signals.

The analog and digital signals then pass through the RF combiner. The signals are broadcast from the headend through optical transmitters to fiber nodes.

Amplifiers, coaxial cable, and taps carry the signals to the subscriber premises. Signals are processed as follows:

Tuners that handle MPEG video, audio and broadcast services in STBs, TVs, and VCRs receive one-way analog signals.
CMs, or tuners in EuroDOCSIS STBs that handle IP data, receive digital data signals:
- Two-way CMs transmit RF signals back through amplifiers to optical fiber receivers at the headend. These receivers pass the upstream signal to upstream ports on the Cisco CMTS where they are processed.
- Telco return CMs transmit over the PSTN. Refer to the "Telco Return" section.

Figure 1-3: Two-Way Internet Access Network Example

Baseline Privacy Interface (BPI)

BPI gives subscribers data privacy across the RF network, encrypting traffic flows between the CMTS and CM.

Note Encryption/decryption is subject to export licensing controls.

The level of data privacy is roughly equivalent to that provided by dedicated line network access services such as analog modems or digital subscriber lines (DSL). BPI provides basic protection of service, ensuring that a CM, uniquely identified by its MAC address, can obtain keying material for services only it is authorized to access.

Note Because DOCSIS 1.0 BPI does not authenticate CMs, it does not protect against users employing cloned CMs, masquerading as authorized CMs. Specific Cisco IOS releases provide protection against spoofing, and support commands that can be used to configure source IP filtering on RF subnets to prevent a user from using a source IP address that is not valid for the connected IP subnet.

BPI is defined as a set of extended services within the DOCSIS MAC sublayer. Refer to the DOCSIS Baseline Privacy Interface Specification for detailed requirements.

BPI extends the definition of the MAC sublayer's SID. The DOCSIS RF Interface Specification defines a SID as a mapping between CMTS and CM to allocate upstream bandwidth and class of service management. When BPI is activated, the SID also identifies a particular security association and has upstream and downstream significance. When BPI is operational, downstream multicast traffic flow that typically does not have a SID associated with it, now has a SID. The Privacy Extended Header Element includes the SID associated with the MAC Packet Data Physical Data Unit (PDU). The SID along with other components of the extended header element identifies to a CM the keying material required to decrypt the MAC PDU's packet data field.

BPI's key management protocol runs between the CMTS and the CM. CMs use the protocol to obtain authorization and traffic keying material relevant to a particular SID from the CMTS and to support periodic reauthorization and key refresh.

The key management protocol uses RSA—a public key encryption algorithm—and the electronic codebook (ECB) mode of DES to secure key exchanges between the CMTS and a CM. Privacy is in the form of 56-bit (the default) or 40-bit encryption between the CMTS and CM. Since BPI is part of DOCSIS, all DOCSIS-certified CMs and qualified CMTS are fully interoperable. Figure 1-4 shows a BPI architecture.

Note CMs must have factory-installed RSA private/public key pairs to support internal algorithms to generate key pairs prior to first BPI establishment.

A SID's keying material has a limited life span. When the CMTS delivers SID keying material to a CM, it also provides the CM with the lifetime value.

Figure 1-4: BPI Network Example

BPI Key Management

BPI initialization begins with the CM sending the CMTS an authorization request, containing data identifying:

CM—48-bit IEEE MAC address
CM's RSA public key
List of zero or more assigned unicast SIDs that have been configured to run BPI

At that time, BPI provides basic protection against theft of service by ensuring the CM, identified by its MAC address, can obtain keying materials only it is authorized to access. The CMTS replies with a list of SIDs on which to run BPI. The reply also includes an authorization key from which the CM and CMTS derive the keys needed to secure a CM's subsequent requests for additional encryption keys. After obtaining the traffic encryption key, the CMs begin to transmit encrypted data.

Differentiating Traffic Streams

BPI only encrypts data on the cable network and only encrypts the user data itself, not cable MAC headers. BPI also does not encrypt MAC management messages.

After BPI is enabled, however, and encryption has been negotiated for a given SID, all user data sent via that SID is encrypted. BPI differentiates traffic, based on SID alone.

CM Communication with BPI

Figure 1-5 illustrates BPI communications. When user A sends packets to user B, the CM encrypts those packets using special keys specific to user's A CM. Packets are then transmitted to the CMTS where they are decrypted.

If user B is attached to the cable TV network, the CMTS then re-encrypts the information using a key specific to user B and the encrypted data is passed to user B's CM where it is decrypted and sent to user B. In this manner, an unauthorized user is not able to see unencrypted traffic between user A and user B.

Caution Since BPI occurs only on the cable TV network, however, all traffic going upstream will be decrypted as it passes the CMTS. If user A is attempting to communicate with someone beyond the cable network—user C—all traffic beyond the CMTS will not be encrypted.

Figure 1-5: BPI Encrypted Data on the Cable TV network

Enabling BPI

To enable BPI, choose software images at both the CMTS and CM that support the mode of operation. For the Cisco CMTS software, choose an image with "k1" in its file name or BPI in the feature set description. For Cisco uBR924 cable access routers, all CM images from Cisco IOS Release 12.0(5)T1 or later support this by default. For earlier Cisco IOS release CM images, choose an image with "k1" in its file name or BPI in the feature set description.

Note For the CMTS, BPI is enabled by default when you select an image that supports BPI. For CMs, enable BPI via the DOCSIS configuration file using one of the provisioning tools identified in the "Cisco CMTS Configuration Tools" section.

When baseline privacy is enabled, the Cisco CMTS generates Traffic Encryption Keys (TEKs) for each applicable SID; 56-bit encryption/decryption is the default for Cisco CMTS equipment.

The router uses the keys to encrypt downstream data and decrypt upstream traffic from two-way cable modems. The Cisco CMTS router generates keys for unicast, broadcast, and multicast operation as appropriate. Keys are refreshed periodically and have a default lifetime of 12 hours.

Virtual Private Network (VPN)

For users and applications requiring a greater level of security than BPI provides, Cisco CMTS software supports Virtual Private Networks (VPNs). A VPN is defined broadly as a private network built over a shared infrastructure. High-speed data circuits are passed to a service provider's facility where the provider terminates subscriber connections and provides backbone connectivity to the Internet. This results in a need to manage subscriber connections and data to and from the Internet.

A VPN can be built on the Internet or through a private IP or IP-plus-ATM infrastructure. Cable-based Intranet VPNs typically connect telecommuters to corporate data centers or branch offices to headquarters so that all locations share the same Intranet. Figure 1-6 illustrates a VPN.

Figure 1-6: VPN Network Example

When offering VPN services, service providers must aggregate diverse services from different carriers and providers. Providers must maintain scaleability and ability to manage and groom individual subscriber data streams into simplified IP flows for backbone routers which carry data throughout the private and public network.

VPN configurations typically involve:

MSO domain which requires a direct peering link to each enterprise network, provisioning servers for residential and commercial subscribers, and dynamic DNS for commercial users. The MSO manages cable interface IP addressing, DOCSIS provisioning, CM hostnames, routing modifications, privilege levels, and VPN-specific usernames and passwords.
Enterprise domain which includes the DHCP server for telecommuter host devices, enterprise gateway within the MSO address space, and static routes back to the telecommuter subnets. The enterprise administrator typically manages Ethernet IP addressing; encryption/decryption maps, policy, keys, transform sets, and interface assignments.

Note Cisco continues to evolve its VPN offerings. Cisco IOS releases support differing VPN feature sets. Refer to the "Feature Lists" section for identification of the Cisco IOS Release T and SC trains and features as of the date of this publication.

Cable Subinterfaces and Interface Bundling

Cisco CMTS software supports the definition of logical network layer interfaces over a cable physical interface or a bundle of cable interfaces. The system supports subinterface creation on either a physical cable interface or a bundle of cable interfaces.

This allows a service provider to share one IP subnet across multiple cable interfaces that are grouped into a cable interface bundle. All of the cable interfaces on a Cisco CMTS can be grouped into a single bundle so that only one subnet is required for each router. This eliminates the requirement that a separate IP subnet be used for each individual cable interface. This in turn avoids the performance, memory, and security problems that result if a bridging solution is used to manage subnets, especially for a large number of subscribers.

The CMTS administrator can:

1. Define subinterfaces on a cable physical interface and assign layer 3 configurations to each subinterface.

2. Bundle a group of physical interfaces and define a bundle master layer 3 configuration or define subinterfaces on the bundle master and give each subinterface layer 3 configurations.

Note Refer to "Configuring and Monitoring Subinterfaces and Cable Bundling"in Chapter 3.

GRE Tunnels

An enterprise can build a private wide area IP network by placing routers at each enterprise site and interconnecting those routers with a private backbone. The Cisco CMTS software supports Generic Routing Encapsulation (GRE) tunnels. GRE tunnels can be defined to provide point-to-point connections between enterprise routers, allowing GRE tunnels to be configured over a cable plant. A tunnel typically starts from the Cisco CMTS router and terminates on an ISP's router.

GRE tunneling of packets allows a layer 3 device to encapsulate packets from one layer 3 domain inside a packet from a second layer 3 domain. This allows the original packet to travel through domains that do not have knowledge of the original domain's address space or routes. The encapsulated IP packets are placed in the payload of an IP type 47 packet.

Tips A tunnel is defined by the source and destination IP address of the tunnel endpoints. These IP addresses are from the domain that carries the GRE packet. The IP subnet from the original packet's domain also describes the tunnel. This allows the tunnel to maintain address continuity from the originating domain.

Note Refer to the "GRE Tunnel Example" section in Chapter 2.

IP Telephony

The Cisco CMTS supports the transmission of digitized VoIP traffic over the cable and IP backbone network to allow MSOs and ISPs to offer voice and fax toll bypass services. Figure 1-7 shows a two-way VoIP configuration.

Figure 1-7: IP Telephony Network Example

The Cisco CMTS equipment and DOCSIS-based CMs that support IP telephony are configured to treat VoIP and regular data traffic separately. The CMTS administrator when creating a configuration for remote CMs configures extra classes of service. These secondary classes of service are expected to be higher QoS classes used for voice. These classes have a minimum upstream rate specified for the channel.

Note Administrators can also associate unique packet flows with a unique SID—multiple SIDs per CM. This is a DOCSIS 1.0 extension feature that both the CMTS and CM must support.

Clock Support

Voice streams are real-time and originate at a synchronized fixed rate. Configuring synchronous clocking for voice applications is important; otherwise overruns and underruns can occur at the cable modem coder-decoder (codec). Clock hardware and software enables high-quality delivery of IP telephony services through synchronized data transmissions. This helps protect against data corruption and loss.

Caution To support the clock feature set, a Cisco uBR7246 VXR chassis must be used. The Cisco uBR7246 VXR must contain a clock card and an MC16S or MC16E cable modem card. Only the MC16S and the MC16E cable modem cards support the external clock reference from the clock card to distribute that signal to CMs and STBs attached to the specific network segments. The chassis must be running Cisco IOS Release 12.1(1a)T1 or higher.

Each CM must also support VoIP applications and the clock reference feature set to enable synchronized timing. The Cisco uBR924 cable access router, running Cisco IOS Release 12.0(7)T or later, supports clock automatically.

The Cisco clock card typically locks to an external T1 timing signal supplied by a global positioning satellite (GPS) receiver or a T1 Building Independent Timing Source (BITS) reference from the PSTN. The clock card drives the time stamp clock for its cable modem cards, which ultimately sends the time stamp downstream to CMs. This provides synchronized timing among the CMs regardless of location. In addition, the clock card automatically provides the timing reference for the midplane TDM clock.

Figure 1-8 shows an example of the cable clock card passing synchronization downstream to Cisco uBR924 cable access routers.

Figure 1-8: Clock Card Providing Synchronization in the Network

The clock card operates in four modes, depending on the timing source:

Locked to external source—The timing signal is coming from a GPS receiver or a PSTN T1 link, traceable to a Stratum 1 atomic clock. This is the normal mode.
Locked to midplane TDM clock—The timing signal is recovered from a T1 trunk connection from a port adapter in the same chassis.

Note A port adapter that supports this feature is not currently available for the Cisco uBR7246 VXR.

Holdover—The primary and secondary external references have failed. The clock card provides a Stratum 3 clock for up to 72 hours if it was able to lock onto the external source for at least 25 seconds. The clock card switches back to an external reference when one becomes available.
Free-running—The primary and secondary external references have failed, and no external source was available long enough for the clock card to enter holdover mode. The 25 ppm crystal on the clock card provides the timing signal.
This mode is the least stable and the least desirable.

If the primary external source fails, the clock card enters holdover mode. After a few seconds, it switches over to the secondary external source. The clock card switches back to the primary external source when it becomes available. Figure 1-9 shows an example of the clocking sources and distribution when the clock card is locked to the primary external source.

Figure 1-9: Clocking Distribution with Clock Card Locked to Primary External Source

Telco Return

In telco return configurations, the Cisco CMTS provides downstream data flow from cable modem cards connected to the cable system and accepts upstream traffic using a combination of the local PSTN and IP network path that terminates at the Cisco CMTS I/O controller or applicable port adapter. Upstream data is through a telephone modem (external or internal to a cable modem, as well as a cable modem card in a PC, based on the third-party cable modem vendor) connected to an analog telephone line typically. Figure 1-10 illustrates a telco return configuration.

Telco return gives cable companies that have not upgraded their cable plants or specific service areas, the ability to offer fast downstream data services via the cable plant and upstream transmission via the PSTN.

Note Because upstream transmission is through the PSTN, MC11 cable modem cards should meet requirements. If a mixed plant is involved or you plan to upgrade to two-way soon, use cable modem cards that support more than one upstream port.

Figure 1-10: Telco Return Network Example

Downstream traffic must be precluded by Telephony Channel Descriptor (TCD) messages to enable upstream telco return traffic. TCD messages contain information necessary for the telco return cable modem to access the headend/ISP network access server (for example, a Cisco AS5300 or Cisco AS5800) over the PSTN.

TCD packets contain three critical telco return elements:

Up to three dial telephone numbers for the telco return cable modem to use when attempting to connect to the headend's network access server
Username and/or MAC address information
Authentication passwords

When connected, the network access server feeds the subscriber user name and password to a RADIUS dial security server. Access is granted or denied. When access has been attained, the network server sets up a Point-to-Point Protocol (PPP) negotiation and connection.

Hot-Standby 1+1 Redundancy

The Hot-Standby 1+1 Redundancy feature offers you the ability to provide high system availability when you configure a Cisco CMTS to wait in hot-standby mode, protecting another Cisco CMTS in case of system failure. The 1+1 redundancy feature provides three to five second automatic system recovery time, thus helping to eliminate "call drops" in the system.

Note It is not uncommon for voice calls in their "setup" phase to be dropped when a CMTS system failure occurs, even with 1+1 redundancy configured on the cable network.

In order for 1+1 redundancy to operate between a Protect CMTS and its Working CMTS peer, the configuration files for the two routers must be exactly the same, excluding configuration commands specific to 1+1 redundancy. Sections of this feature module describe the necessary differences in configuration between a Protect CMTS and its Working CMTS peer.

Protection Scenarios

Configuration for 1+1 redundancy takes place at the cable modem card interface level. That is, rather than assigning an entire Cisco uBR7200 series to support another Cisco uBR7200 series, you configure individual interfaces on one Cisco uBR7200 series to protect individual interfaces installed in a different Cisco uBR7200 series.

The protection scenario currently available for Cisco uBR7200 series routers is the 1+1 scenario.

1+1 Protection

In a 1+1 redundancy protection scheme, the protecting cable modem card interface in the Protect CMTS and working cable modem card interface in the Working CMTS are each connected to the same downstream combiner/splitter and the same upstream combiner/splitter. See Figure 11. In the event of a system failure in the Working CMTS, the Protect CMTS assumes data and voice traffic responsibilities by switching both the upstream and downstream connections at the combiner/splitters from the Working CMTS to the Protect CMTS.

Note 1+1 redundancy protection takes place on an inter-chassis basis, only. That is, you can't protect cable interfaces on a particular CMTS with cable interfaces installed in the same chassis.

Figure 11: Sample Cable Headend Deployment Featuring 1+1 Redundancy Protection

High Availability

The 1+1 redundancy feature provides three to five second automatic system recovery time in the event of system failure, thus helping to eliminate unwanted "call drops." System failure in a non redundancy (unprotected) deployment results in loss of all voice calls in progress as well as all voice calls in "setup" phase because the CMTS requires human intervention to reconfigure and bring the CMTS back on line.

Cisco IOS Releases and Software/Hardware Matrix Tables

This section identifies the Cisco CMTS features for the new Cisco IOS EC train and the Cisco IOS Release T and Cisco IOS Release SC trains, and lists the latest images in the trains. The section further provides software and hardware matrix tables for key components.

Feature Lists

Table 1-1 lists the supported features for Cisco IOS Releases 12.0 and 12.1 T trains as of the date of this publication. Table 1-2 lists cable-specific features for cable's stable Cisco IOS Release 12.0 SC train. Both tables list the release the feature was first supported, categorizes the feature, and briefly describes it.

Note In general, later software releases within the same train include the feature set supported earlier and add new features. Refer to the Cisco IOS Command Reference Master Index(s) for a detailed listing of all Cisco IOS releases and supported features.
Table 1-1: Cisco CMTS T Early Deployment Feature List

Name

Category

Description

Cisco IOS Release 12.0(3)T

WCCP and WCCPv2

Cache

Identifies the web caching protocols supported.

Committed Access Rate (CAR)

QoS

Provides the means to allocate and limit bandwidth to traffic sources and destinations, and specify policies to handle traffic exceeding the bandwidth allocation. CAR policies can be utilized at the ingress or egress of the network. The feature uses token bucket filters to measure traffic load and limit sources to bandwidth allocations.

Cisco Express Forwarding (CEF)

QoS

Supports Cisco's processing switching protocol to enable traffic decisions to be made quickly.

Weighted Random Early Detection (WRED)

QoS

Provides the ability to specify traffic handling policies to maximize throughput under congestion conditions. RED works in conjunction with TCP to intelligently avoid network congestion. WRED combines IP precedence and RED capabilities to provide differentiated performance characteristics for different classes of service, thus providing preferential traffic handling for higher priority traffic. Administrators can define minimum and maximum queue depth thresholds and drop probabilities for each class of service.

TAG/NetFlow Switching

QoS

Provides high performance for network layer services, enabling per-flow application of network services such as security and traffic accounting. Data collected for each flow includes:

Source and destination IP address
Start of flow and end of flow timestamps
Packet and byte counts
Next hop router address
Input and output physical port interfaces
Source and Destination TCP/UDP port numbers
IP protocol type
Type of service (ToS) field
TCP flags
Source and destination autonomous system numbers
Source and destination subnet masks

Weighted Fair Queuing (WFQ)

QoS

Performs priority output queuing and custom queuing to grant resources to important sessions when network bandwidth is saturated; typically used for digitized voice packets to help reduce delay. WFQ provides expeditious handling for high priority traffic, requiring low delay, while fairly sharing the remaining bandwidth between lower priority traffic. WFQ divides link traffic into high and low priority flows based on metrics including IP precedence and traffic volume.

Resource Reservation Protocol (RSVP)

QoS

Works in conjunction with WFQ; helps the router establish a weight for different types of packets that affect the order in which the packets enter the output queue and are placed on the cable network for transmission; that is, voice packets are routed through the interface with a QoS method that allows the packets to receive priority over standard data frames. A router that supports RSVP gives priority to packets that fall into a reservation within RSVP.

Integrated DHCP Server

Network Management

Simplifies provisioning, offering an integrated Dynamic Host Configuration Protocol server.

Simple Network Management Protocol (SNMP) v3

Network Management

SNMP version 3 offers enhanced security features and increases interoperability. The implementation set of MIBs allows the SNMP manager to gather data such as system card descriptions, serial numbers, hardware and software revision levels, slot location, among other data.

Cisco IOS Release 12.0(5)T1

DHCP Client ID/Remote ID Options

(also known as Customer Premises Equipment (CPE) Limitation)

Provisioning

Allows the Cisco CMTS to report and limit the number of CPEs per cable modem through command-line interface (CLI) and Simple Network Management Protocol (SNMP).

DHCP Cable Modem Host ID

(also known as Cable Modem and Host Subnet Addressing)

Provisioning

Allows the Cisco CMTS to modify the giaddr field of DHCPDISCOVER packets, based on whether the source is a cable modem or a host. This helps automate provisioning.

Cisco IOS Router Operating System

Routing

Performs enhanced route filtering and translation to save network resources and prevent data from being broadcast to nodes that do not require it.

Cable Modem Multicast Authentication (RADIUS)

Routing

Permits RADIUS to be used to authenticate subscribers.

Per Modem Filters

(also known as Per Modem and Per Host Access Lists)

Routing

Allows the Cisco CMTS to filter incoming packets from individual hosts or cable modems based on the source Media Access Controller (MAC) or Internet Protocol (IP) address. This allows access lists to be specified on a per-interface and per-direction basis. The packets received from cable modems and/or individual hosts are filtered based on the cable modem or the host the packets are received from.

Interswitch Link (ISL) Bridging (Noncable Interfaces)

Bridging

Provides support for the ISL feature—Cisco protocol used to interconnect multiple routers and switches and maintain Virtual Local Area Network (VLAN) information as traffic is conveyed between the routers and switches.

DOCSIS Software Infrastructure

Operations

Supports CableLabs specifications for high-speed data-over-cable systems involving the following categories:

RF interfaces between the Cisco CMTS and the cable network—Downstream and upstream traffic.
Data interfaces for cable modems and CPE devices, as well as the CMTS network-side interface between the Cisco CMTS routers and the data network.
Operations support interfaces—Network element management layer interfaces between the network elements and the operations support systems.
Telco return interfaces—Interfaces between third-party DOCSIS-compliant cable modems and the telco return path(s) when the return path is not provided by the cable network.

DOCSIS 1.0 Media Access Controller (MAC) Driver

Operations

Supports CableLabs specifications for the MAC sublayer and associated interfaces.

Integrated Time of Day (ToD) Server

Operations

Allows the Cisco CMTS to respond to ToD (RFC 868) queries from cable modems during the registration process.

Downstream Channel ID

Operations

Allows all cable modems on the cable network to have unique downstream channel IDs. CMs communicate their downstream ID when making a connection, and not the downstream frequency.

Cisco Online Insertion Removal (OIR)

Operations

Allows key components such as cable modem cards and port adapters to be removed and replaced without powering off the chassis.

Downstream Frequency Override

Operations

Allows the Cisco CMTS to change the downstream frequency for a cable modem, overriding the DOCSIS configuration file setting.

Basic Wiretap Support

Operations

Provides support for a basic wiretap facility that the United States Federal Communications Assistance for Law Enforcement Act (CALEA) requires. This provides a mechanism such that user-to-user traffic can be captured.

The wiretap facility is based on the MAC address of the RF CPE device, so it can be used for either data or digitized voice connections. The feature is controlled by the new interface command— cable intercept—which requires a MAC address, an IP address, and a UDP port number as its parameters.

When activated, the Cisco CMTS examines each packet for the desired MAC address. When a matching MAC address is found (for either the origination or destination endpoint), a copy of the packet is encapsulated into a UDP packet, which is then sent to the specified server at the given IP address and port.

Spectrum Management
Phases 1 and 2

Spectrum Management

Supports the following spectrum management capabilities to specify the rules the system uses when hopping to another frequency when no clean frequency band is available:

Combined blind and time scheduled reassignment:
- Blind hop—No "look ahead" capabilities, but some specifications on frequency reassignment based on the number of lost station management messages exceeding a threshold (default=10).
- Time scheduled—Frequency reassignment based on time of day or week.
Guided frequency hop—Assigning explicit frequency subbands and associated input power levels in a spectrum group.

Upstream Address Verification

Security

Supports verification of cable modem and PC addresses to ensure cable modem SID and MAC addresses are consistent; this helps ensure IP addresses are not spoofed. A PC behind a cable modem is assigned an IP address from the DHCP server. If a user on a second PC/cable modem statically assigns the same IP address to a PC, the Cisco CMTS will find this case to help block the spoofing user. Using the CLI, administrators can determine the IP and MAC address of a given cable modem, and the SID number that shows the IP and MAC addresses of all devices learned in the cable modem's MAC table. Using the service provider's customer databases, administrators can cross reference the spoofing cable modem and PC and prevent usage.

40-bit and 56-bit Baseline Privacy Data Encryption Standard (DES)

Security

The Cisco CMTS supports 40-bit and 56-bit encryption/decryption. When encryption/decryption is enabled, 56-bit is the default. If wanted, administrators can force the Cisco CMTS to generate a 40-bit DES key, where the DES key that is generated and returned masks the first 16-bits of the 56-bit key to zero in software.

Note Requires software images that support the BPI feature set both at the CMTS and CM.

Cisco IOS Firewall

Security

Supports Network Address Translation (NAT) and firewall functionality.

DOCSIS 1.0 QoS

QoS

Supports definition of service class profiles according to DOCSIS 1.0:

Traffic priority (7, 6, 5, 4, 3, 2, 1, 0) with 7 being the highest
Maximum upstream rate in bps
Maximum upstream channel burst in minislot
Minimum upstream rate in bps
Maximum downstream rate in bps

DOCSIS 1.0 QoS Extensions

QoS

Allows the Cisco CMTS to specify priority service flows higher than those specified in DOCSIS 1.0.

Multi-SID Support

QoS

Allows the Cisco CMTS to support the definition of multiple SIDs on the upstream. This includes multiple service classes per cable modem, enabling administrators to give voice and fax data a higher priority.

Upstream Rate Shaping

QoS

Supports buffering upstream grants from rate-exceeding cable modems, without incurring Transmission Control Protocol (TCP)-related timeouts and retransmits.

Downstream Rate Shaping

QoS

Supports buffering downstream grants to rate-exceeding cable modems, without incurring TCP-related timeouts and retransmits.

Downstream Rate Shaping to include Type of Service (ToS)

QoS

Enables downstream traffic to be partitioned into multiple classes of service. Uses the three precedence bits in the ToS field in the IP header to specify class of service assignment for each packet. Those packets with the IP precedence bit set in the IP packet are given higher priority.

This allows the CMTS administrator to calculate the data rate for a given flow, in addition to the data rate configured on a per cable modem basis.

QoS Profile Enforcement

QoS

Allows the Cisco CMTS to override the provisioned service class of a cable modem at the time of registration with a CMTS-defined QoS profile.

Telco Return

Allows the Cisco CMTS to register third-party DOCSIS-compliant telco return cable modems, based on the DOCSIS telco return specification. This allows the network to support two-way and telco return cable modems.

RF Interface Management Information Base (MIB)

Network Management

Supports objects related to RF management.

Service Class Setting Using SNMP

Network Management

Supports objects related to class of service.

DOCSIS Extensions MIB

Network Management

Supports objects related to QoS support for scheduler of DOCSIS-compliant RF interfaces in the CMTS.

RFI MIB Update,
Improved
Traps

Network Management

Improves object support for SNMP traps; traps are the mechanisms used to automatically send alarms for certain network events.

Cisco IOS Release 12.0(7)T

Enhanced Source Address Verification

Operations

Prevents the spoofing of IP addresses by verifying that each upstream data packet comes from the CM known to be associated with the source IP address in the packet. The cable source-verify [dhcp] cable interface command specifies that DHCP lease query requests are sent to verify any unknown source IP address found in upstream data packets.

Note This feature requires a DHCP server that supports the new LEASEQUERY message type such as Cisco Network Registrar (CNR) version 3.01(T).

Per SID Bandwidth Request/Grant Counters

Operations

Promotes better control of voice calls, permitting per-SID bandwidth requests and grants. Profiles can be customized for scheduling parameters required at subscriber sites for the service offering. The show interface cx/0 upstream number now supports a verbose option that displays:

Number of bandwidth requests successfully received by the Cisco CMTS from the specified SID on the specified cable interface
Number of grants issued by the Cisco CMTS to the specified SID

Configurable Registration Timeout

Operations

Changes the CM registration value (the T9 timer); the cable registration-timeout minutes command sets the T9 timer to the new value (from 2 to 60 minutes). The no cable registration-timeout command resets the T9 timer to its default of 3 minutes.

Statistical Values Added to show controller int cx/y upstream Command

Operations

Displays the following additional statistical counters in the output of the show controller cx/0 upstream number. The command displays:

Average percent of upstream utilization in minislots
Average percent of contention slots
Average percent of initial ranging slots
Average percent of minislots that were due because the MAP scheduler was not able to request them in time

Telco Return RADIUS Enhancements

Operations

Provides additional authentication information, allowing an administrator to determine if a subscriber dialed a number that requires special billing arrangements (such as a toll-free number). If a telco return customer is being authenticated by a Terminal Access Controller Access Control System Plus (TACACS+) or RADIUS server, and if the number dialed by the CM is being redirected to another number for authentication, the system can include the original number in the information sent to the authentication server. The original number can be sent as a Cisco Vendor Specific Attribute (VSA) for TACACS+ servers and as RADIUS Attribute 93 (Ascend-Redirect-Number) for RADIUS servers.

Downstream Signal Test Commands

DOCSIS

Provides the following test capabilities: the cable downstream if-output command is enhanced with the following options to generate test signals on the downstream interface:

cable downstream if-output prbs shuts down the downstream interface and outputs a PRBS test signal
cable downstream if-output continuous wave shuts down the downstream interface and outputs an unmodulated carrier signal

The previous cable downstream if-output command has not changed and continues to output a standard modulated signal. The no cable downstream if-output command has not changed; it stops all signal output and shuts down the interface.

Modem Power Enhancement Adjustments for low SNR Failures

DOCSIS

Allows Cisco CMTS to better adjust when a CM seems to bounce—the CM requires frequent power adjustments in opposite directions. When this occurs, instead of making large power adjustments for each correction, the administrator can configure the Cisco CMTS to calculate the average value of the power corrections before making power adjustments:

cable upstream power-adjust threshold command now accepts a range of 0-10 dB (the previous range was 0-2 dB)
cable upstream power-adjust noise % of power adjustment command sets the threshold value (in percent) for a particular upstream, switching between regular power adjustments and the noise power adjustment method.

The noise power adjustment method uses an averaging algorithm before sending any correction.

EuroDOCSIS Support via MC16E

EuroDOCSIS

Allows support of EuroDOCSIS Annex A standard to support 8 MHz PAL or SECAM channel plan operation (similar to DAVIC/DVB ITU J.83 standard).

The MC16E has a downstream 36.125 MHz interface, with a 8 MHz channel width and interleave factor of I=12, J=17. The card supports a downstream symbol rate of 6.592 Msymbols/sec at 64 QAM and 256 QAM. The downstream channel range supported is 85 to 860 MHz; the upstream channel range supported is 5 to 65 MHz.

Weighted Fair Drop (WFD) Enhancements

QoS

In addition to other traffic shaping techniques, a new configuration field associates a maximum bandwidth in kbps with a particular setting of IP type of service (ToS) bits. This can be used to ensure that certain traffic, such as data, does not exceed a pre-set rate limit and thereby interfere with higher priority real-time traffic such as voice.

Cisco IOS Release 12.0(7)XR2

Concatenation Support

DOCSIS

Combines multiple upstream packets into one packet to reduce packet overhead and overall latency, as well as increase transmission efficiency. Using concatenation, a CM needs to make only one bandwidth request for a concatenated packet, as opposed to making a different bandwidth request for each individual packet. This technique is particularly effective for real-time traffic such as voice calls.

DOCSIS 1.0 Constant Bit Rate (CBR)—DOCSIS 1.0 Extension

DOCSIS QoS

Enables better processing of voice; new fields in the DOCSIS configuration file can be used so that when a CM requests a voice SID, the MAC scheduler on the Cisco CMTS schedules fixed periodic slots on the upstream for that traffic flow. The CM does not have to contend for these slots, and because the Cisco CMTS controls the timing of slots, it has precise control over potential delay and jitter.

Hardware-based Spectrum Management Enhancements using the MC16S

Spectrum Management

Provides advanced spectrum management capabilities through a card that contains a spectrum analyzer that samples the 5 to 42 MHz upstream frequency spectrum in real-time, and analyzes the number of offline CMs. If an administrator-defined threshold is reached, the card takes a snapshot of the available upstream segment and passes that information to the Cisco IOS software, which analyzes it for possible significant ingress and impulse noise. Using this analysis, the Cisco IOS software evaluates the upstream frequency spectrum and if necessary automatically hops to a frequency that can provide a clean upstream channel. This eliminates blind frequency hops and can improve response time to ingress noise impairments.

The cable upstream interface command now includes a parameter to allow the creation of a range of channel widths when using the MC16S cable modem card. The new syntax is cable upstream port channel width channel-width-1, channel-width-2 where the possible channel width values are 200000, 400000, 800000, 1600000, 3200000. The cable upstream port modulation-profile modulation-number command configures the upstream modulation profile.

Note The MC16S card is calibrated using a 24.016 MHz, 0 dBmV reference signal injected into the card's front F-connector. The worst case accuracy is specified as +/- 3 dB over the DOCSIS upstream frequency band (5 to 45 MHz) and operating temperature range (0 to 40 degrees Centigrade).

Modem Status Display Enhancements

Operations

Supports polling of CMs to obtain parameter and status information on an ongoing basis. Two new Cisco IOS commands are added to support the feature:

The cable modem remote command configures the router for the polling interval; the no version of this command disables the status polling.
The show cable modem remote-query command displays the collected information: downstream receive power level, downstream signal to noise ratio, upstream power level, micro reflection in dB.

Additional or changed show commands include:

The show cable qos command shows cable qos-profile n command, where the optional argument n can be used to display a specific profile.
The show int cx/y sid command displays more complete Service ID (SID) status information.
The show cable modem command displays a list of options for a single modem to be specified by entering either the RF CPE device's IP address or MAC address: SNR information for each CM on each interface, summary display of the total number of modems connected for each upstream channel, total number of registered and unregistered modems for the specified interface or upstream, total number of offline modems for the specified interface or upstream and status for each offline modem before it went offline.
The show cable burst-profile command has been removed. Its functions have been incorporated into the show cable modulation-profile command, which now includes an added option number that displays the modulation profile number.
The show cable flap-list and show cable modem commands now indicate when the Cisco CMTS has detected an unstable return path for a particular modem and has compensated with a power adjustment. An asterisk appears in the power adjustment field for a modem when a power adjustment has been made; an exclamation point appears when the modem has reached its maximum power transmit level and cannot increase its power level any further.

Interface Bundling

Bridging

Allows a service provider to share one IP subnet across multiple cable interfaces that are grouped into a cable interface bundle. All of the cable interfaces on a Cisco CMTS can be grouped into a single bundle so that only one subnet is required for each router. This eliminates the requirement that a separate subnet be used for each individual cable interface. This in turn avoids the performance, memory, and security problems that would result if a bridging solution were used to manage the subnets, especially for a large number of subscribers. Two new commands implement this feature:

cable bundle number [master]—Configures cable interfaces into bundles.
show cable bundle number forwarding table—Displays all the currently known cable devices in the bundle.

Cable Subinterfaces (multiple-ISP support)

VPN

Supports the creation of subinterfaces on cable interfaces or cable interface bundles to support VPN over the cable interface. Each subinterface is assigned to a specific pool of IP addresses, mapping that subinterface to a particular VPN customer network. A Generic Routing Encapsulation (GRE) tunnel is created typically between the Cisco CMTS and the router that serves as the VPN customer gateway.

Note This release does not include MPLS support as part of its VPN support on the cable subinterface.

TAG Switching Support on Cable Interfaces

VPN

Supports enhancements made to tags placed on the fronts of packets that contain forwarding information used for making switching decisions for cable interfaces. A tag switching infrastructure combines advanced routing protocol capabilities to define IP VPNs by selectively advertising IP reachability information to just those subscribers within the same VPN or extranet on a cable interface.

Cisco IOS Release 12.1(1a)T1

Support for Dynamic/Mobile Hosts

Operations

Allows the CMTS administrator to bring up a PC behind one CM, then move it to another CM. Adds information for the hosts involved in host tables. To prevent security breaches, supports pinging the host using the old SID to verify that it has indeed been moved.

DHCP server is used to verify addresses and can be configured with the cable source-verify dhcp command; no cable arp should be configured in the CMTS to prevent it from sending ARP requests.

Clock Card Support

Operations

Enables the Cisco uBR7245 VXR, equipped with a clock card, to synchronize to an external timing reference and distribute the clock to MC16S or MC16E cable modem cards. The synchronized time stamps are then passed downstream to all CMs.

The clock card is designed for cable networks running VoIP applications where synchronized timing is vital to maintain voice quality.

Table 1-2 lists the cable-specific features in the Cisco CMTS SC release train. SC is an early deployment release, providing a stable platform for cable products with essential new features and fixes to software.

Tips Cisco IOS Release 12.0 SC software supports only two-way DOCSIS and EuroDOCSIS-based CMs and set top box (STB) units with integrated EuroDOCSIS modems. The SC release excludes telco-return or DOCSIS 1.0 extension support.

Note Cisco IOS Release 12.0(6)SC was the first release of the train. Features were ported from Cisco IOS Release 12.0(5)T1.
Table 1-2: Cisco CMTS SC Cable-Specific Release Feature List

Name

Category

Description

Cisco IOS Release 12.0(6)SC

Encrypted Baseline Privacy Key Exchange

Security

Supports full DOCSIS 1.0 BPI specifications

DOCSIS QoS Enhancements

DOCSIS

Supports definition of service class profiles according to DOCSIS 1.0:

Traffic priority (7, 6, 5, 4, 3, 2, 1, 0) with 7 being the highest
Maximum upstream rate in bps
Maximum upstream channel burst in minislot
Minimum upstream rate in bps
Maximum downstream rate in bps

Spectrum Management
Phases 1 and 2
(excludes MC16S support)

Spectrum Management

Supports the following spectrum management capabilities to specify the rules the system uses when hopping to another frequency when no clean frequency band is available:

Combined blind and time scheduled reassignment:
- Blind hop—No "look ahead" capabilities, but some specifications on frequency reassignment based on the number of lost station management messages exceeding a threshold (default=10).
- Time scheduled—Frequency reassignment based on time of day or week.
Guided frequency hop—Assigning explicit frequency subbands and associated input power levels in a spectrum group.

Downstream Channel ID

Operations

Allows all cable modems on the cable network to have unique downstream channel IDs assigned.

Note Full operational capability is found in Cisco IOS Release 12.0(8)SC1.

Cisco Online Insertion Removal (OIR)

Operations

Allows key components such as cable modem cards and port adapters to be removed and replaced without powering off the chassis.

Downstream Frequency Override

Operations

Allows the Cisco CMTS to change the downstream frequency for a cable modem, overriding the DOCSIS configuration file setting.

Upstream Traffic Shaping

QoS

Supports buffering upstream grants from rate-exceeding cable modems, without incurring TCP-related timeouts and retransmits.

Downstream Rate Shaping with ToS

QoS

Enables downstream traffic to be partitioned into multiple classes of service. Uses the three precedence bits in the ToS field in the IP header to specify class of service assignment for each packet.

Those packets with the IP precedence bit set in the IP packet are given higher priority. This allows the CMTS administrator to calculate the data rate for a given flow, in addition to the data rate configured on a per cable modem basis.

Cisco IOS Release 12.0(8)SC1

EuroDOCSIS Support via MC16E

EuroDOCSIS

Allows support of EuroDOCSIS Annex A standard to support 8 MHz PAL or SECAM channel plan operation (similar to DAVIC/DVB ITU J.83 standard).

The MC16E has a downstream 36.125 MHz interface, with a 8 MHz channel width and interleave factor of I=12, J=17. The card supports a downstream symbol rate of 6.592 Msymbols/sec at 64 QAM and 256 QAM. The downstream channel range supported is 85 to 860 MHz, The upstream channel range supported is 5 to 65 MHz.

Interface Bundling

Bridging

This eliminates the requirement that a separate subnet be used for each individual cable interface. This in turn avoids the performance, memory, and security problems that would result if a bridging solution were used to manage the subnets, especially for a large number of subscribers.

Two new commands implement this feature:

cable bundle number [master]—Configures cable interfaces into bundles.
show cable bundle number forwarding table—Displays all the currently known cable devices in the bundle.

Cable Subinterfaces (multiple-ISP support)

VPN

Note This release does not include MPLS support as part of its VPN support on the cable subinterface.

Cisco IOS Release 12.0(9)SC

Support for Dynamic/Mobile Hosts

Operations

Allows CMTS administrator to bring up a PC behind one CM, then move it to another CM. Adds information for the hosts involved in host tables. To prevent security breaches, supports pinging the host using the old SID to verify that it has indeed been moved.

DHCP server is used to verify addresses and can be configured with the cable source-verify dhcp command; no cable arp should be configured in the CMTS to prevent it from sending ARP requests.

Support for RFC 2233 (RF Interface MIB)

Network Management

Support DOCSIS OSSI Required Objects in RFC 2233 for the Cisco CMTS

Implement RFC 2665 Support for Cisco uBR7200 Series

Network Management

Support DOCSIS OSSI Required Objects in RFC 2665 for the Cisco CMTS

New Cisco IOS EC Release Train

There is now a new cable-specific, leading-edge release train, the EC train. Release 12.1 EC was the first EC train and was an early deployment (ED) release based on the Release 12.1(1a) T1 feature set, as the starting point for the EC train. Early deployment releases contain fixes to software caveats as well as support for new Cisco hardware and software features. Feature support is cumulative from release to release, unless otherwise noted. Table 1-3 shows the features associated with the EC train.Table 1-3 lists the features supported by the Cisco uBR7200 series in Cisco IOS Release 12.1(3a) EC.

Table 1-3: Early Deployment (ED) Releases for the Cisco uBR7200 Series

ED Release Additional Software Features¹ and MIBs² Additional Hardware Features Hardware
Availability

12.1(3a) EC

New in Release 12.1(3a) EC:

Hot-Standby 1+1 Redundancy

Dynamic Upstream Modulation

Cable Monitor

Cable Interface Setup Facility

Overlapping Subinterface IP Addresses

MC28 Cable Modem Card

10/00

12.1(3a) EC

Enhancements were made to the following MIBs:

CISCO-DOCS-EXT-MIB

DOC-IF-MIB

12.1(2) EC1

New in Release 12.1(2) EC1:

MPLS³ VPN⁴ Support for Subinterfaces and Interface Bundles

Dynamic Ranging Support

Enhanced Per-Modem Error Counter

Configurable Alternate Termination System Information Messages

Internal Modem Configuration File Editor

"max-cpe" CLI override

Port Adapters:

Dynamic Packet Transport

PA-SRP-OC12SML

PA-SRP-OC12SMI

PA-SRP-OC12MM

PA-4E1G/120

PA-E3

PA-MC-4T1

PA-MC-8T1

PA-A3-T3

PA-A3-E3

PA-4T+

PA-8T-V35

PA-8T-X21

Now

12.1(2) EC1

New MIBs Supported:

DOCSIS Ethernet MIB Objects Support (RFC⁵ 2665)

DOCSIS OSSI⁶ Objects Support (RFC 2233)

Multicast BPI⁷ MIB Support

Link Up/Down Traps Support (RFC 2233)

SNMP⁸ Cable Modem Remote Query

SNMP Objects for Clear Host, Clear Cable Modem, and Show Current CPEs⁹

¹Only major features are listed.
²MIB = Management Information Base
³MPLS = Multiprotocol Label Switching
⁴VPN = Virtual Private Network
⁵RFC = Request For Comments
⁶OSSI = Operations Support System Interface
⁷BPI = baseline privacy interface
⁸SNMP = Simple Network Management Protocol
⁹CPE = customer premises equipment

Cisco IOS Images

Cisco IOS Release 12.1(1a)T1 Images

Table 1-4 identifies the Cisco IOS Release 12.1(1)T images—the most recent early deployment release as of the date of this publication.Cisco IOS Release 12.1(1a)T1 Images
Table 1-4: Cisco CMTS Cisco IOS Release 12.1(1a)T1 Images

Image Description

Two-Way Data/VoIP and Wireless Images

ubr7200-is-mz

IP routing and bridging, NAT, ISL, and VPN support

ubr7200-ik1s-mz

IP routing and bridging, baseline privacy, NAT, ISL, and VPN support

ubr7200-k1p-mz

IP routing with IS-IS, BGP, and baseline privacy (no bridging and no NAT)

ubr7200-p-mz

IP routing with IS-IS and BGP (no bridging and no NAT)

Telco Return Images

ubr7200-ik1st-mz

IP routing and bridging, baseline privacy, NAT, ISL, and DOCSIS telco return

ubr7200-ist-mz

IP routing and bridging, NAT, ISL, and DOCSIS telco return

The image subset legend for Table 1-4 follows:

i = IP routing and non-cable interface bridging including Network Address Translation (NAT)
p = IP routing with Intermediate System-to-Intermediate System (IS-IS) and Border Gateway Protocol (BGP); no bridging and no NAT
k1 = DOCSIS Baseline Privacy which is subject to export controls
s = "Plus" features: NAT and Inter-Switch Link (ISL)
t = DOCSIS telco return

Cisco IOS Release 12.0(9)SC Images

Table 1-5 identifies the Cisco IOS Release 12.0(9)SC images—the most recent Cisco IOS stable release as of the date of this publication.

Table 1-5: Cisco CMTS Cisco IOS 12.0(9)SC Release Images

Image Description

Two-Way Data/VoIP Images

ubr7200-p-mz

IP routing and bridging, NAT, ISL, and VPN support

ubr7200-ps-mz

IP routing and bridging, baseline privacy, NAT, ISL, and VPN support

ubr7200-k1p-mz

IP routing with IS-IS, BGP, and baseline privacy (no bridging and no NAT)

ubr7200-k1ps-mz

IP routing with IS-IS and BGP (no bridging and no NAT)

The image subset legend for Table 1-5 is as follows:

p = IP routing with Intermediate System-to-Intermediate System (IS-IS) and Border Gateway Protocol (BGP); no bridging and no NAT
k1 = DOCSIS Baseline Privacy which is subject to export controls
s = "Plus" features: NAT and Inter-Switch Link (ISL)

Note All Cisco IOS Release 12.0 SC images require 64 MB of DRAM.

Cisco Cable Modem Card Release Matrix

Table 1-6 lists Cisco cable modem cards and identifies the chassis and train releases the cards were first supported on.

Table 1-6: Cisco CMTS Cable Modem Card Releases

Cisco Cable Modem Card Cisco uBR7223 Cisco uBR7246 Cisco uBR7246 VXR

MC11FPGA

Note   No longer orderable

11.3(6)NA 12.0(2)XC 12.0(3)T 12.0(6)SC

Note   Will not work with NPE-175 or NPE-225

11.3(2)XA 11.3(3)T 11.3(6)NA 12.0(2)XC 12.0(3)T 12.0(6)SC

Note   Will not work with NPE-175 or NPE-225

Not applicable

MC11C

11.3(5)NA 12.0(5)T1 12.0(6)SC

11.3(6)NA 12.0(3)T 12.0(6)SC

12.0(7)T 12.0(7)SC

MC12C

11.3(5)NA 12.0(5)T1 12.0(6)SC

11.3(6)NA 12.0(3)T 12.0(6)SC

12.0(7)T 12.0(7)SC

MC14C

11.3(5)NA 12.0(3)T 12.0(6)SC

11.3(5)NA 12.0(3)T 12.0(6)SC

12.0(7)T 12.0(7)SC

MC16B

Note   No longer orderable

11.3(6)NA 12.0(2)XC 12.0(3)T 12.0(6)SC

11.3(6)NA 12.0(2)XC 12.0(3)T 12.0(6)SC

Not applicable

MC16C

11.3(9)NA1 12.0(2)XC 12.0(3)T 12.0(6)SC

11.3(8)NA 12.0(3)T 12.0(6)SC

12.0(7)T 12.0(7)SC

MC16S
12.0(7)XR2 12.1(1a)T1

12.0(7)XR2 12.1(1a)T1

12.0(7)XR2 12.1(1a)T1

MC16E

12.0(7)T 12.0(8)SC1

12.0(7)T 12.0(8)SC1

12.0(7)T 12.0(8)SC1

MC28C

12.1(3)EC

12.1(3)EC

12.1(3)EC

Cisco Port Adapter Release Matrix

Table 1-7 lists current Cisco CMTS port adapters and identifies the chassis and release trains on which the port adapter was first supported.
Table 1-7: Cisco CMTS Port Adapter Releases

Product Number Cisco uBR7223 Cisco uBR7246 Cisco uBR7246 VXR

Ethernet

PA-4E—4-port Ethernet 10BaseT port adapter

11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(7)SC, 12.0(7)T, 12.1(1a)T1 ¹, 12.1(2)EC1

PA-8E—8-port Ethernet 10BaseT port adapter

11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(7)SC, 12.0(7)T, 12.1(1a)T1 ², 12.1(2)EC1

PA-FE-TX—1-port 100BaseTX Fast Ethernet port adapter

11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1

PA-FE-FX—1-port 100BaseFX Fast Ethernet port adapter

11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1

PA-2FEISL-TX—2-port 100BaseTX Fast Ethernet port adapter with Inter-Switch Link (ISL) support

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1

PA-2FEISL-FX—2-port 100BaseFX Fast Ethernet port adapter with Inter-Switch Link (ISL) support

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1

PA-12E/2FE—12-port 10BaseT and 2-port 10/100BaseTX port adapter

Not applicable

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

Gigabit Ethernet

PA-GE—1-port, full-duplex, IEEE 802.3z- compliant Gigabit Ethernet (GE) port adapter³

Not applicable

Not applicable

12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1

Serial

PA-4T+—4-port synchronous serial port adapter

11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(10)SC, 12.1(1a)T1

PA-8T-232—8-port EIA/TIA-232 synchronous serial port adapter

11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-8T-V35—8-port V.35 synchronous serial port adapter

11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-8T-X21—8-port X.21 synchronous serial port adapter

11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.1(2)EC1

PA-4E1G-75—4-port unbalanced (75-ohm) E1-G.703/G.704 synchronous serial port adapter

11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-4E1G-120—4-port balanced (120-ohm) E1-G.703/G.704 synchronous serial port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-E3—1-port high-speed serial E3 interface port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-T3—1-port T3 serial interface port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-2E3—2-port high-speed serial E3 interface port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-2T3—2-port T3 serial interface port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-MC-E3—1-port multi-channel E3, medium-speed serial interface port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-MC-T3—1-port T3 (channelized into 28 independent T1 data lines) port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-MC-4T1—4-port multichannel DS1 Integrated Services Digital Network (ISDN) Primary Rate Interface (PRI) single-wide port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-MC-8E1/120—8-port multichannel E1 Integrated Services Digital Network (ISDN) Primary Rate Interface (PRI) single-wide port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-MC-8T1—8-port multichannel DS1 Integrated Services Digital Network (ISDN) Primary Rate Interface (PRI) single-wide port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

HSSI

PA-H—1-port HSSI port adapter

11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(7)SC, 12.0(7)T, 12.1(1a)T1 ⁴, 12.1(2)EC1

PA-2H—2-port HSSI port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(7)SC, 12.0(7)T, 12.1(1a)T1 ⁵, 12.1(2)EC1

ATM

PA-A1-OC3SMI—1-port ATM OC-3c/STM-1 single-mode intermediate reach port adapter

11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-A1-OC3MM—1-port ATM OC-3c/STM-1 multimode port adapter

11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-A2-4E1XC-OC3SM—5-port ATM CES⁶ (4 E1 120-ohm CBR⁷ ports and 1 OC-3 ATM single-mode port) port adapter

Not applicable

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-A2-4E1XC-E3ATM—5-port ATM CES⁶ (4 E1 120-ohm CBR⁷ ports and 1 E3 ATM port) port adapter

Not applicable

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-A2-4T1C-OC3SM—5-port ATM CES⁶ (4 T1 CBR⁷ ports and 1 OC-3 ATM single-mode port) port adapter

Not applicable

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-A2-4T1C-T3ATM—5-port ATM CES⁶ (4 T1 CBR⁷ ports and 1 T3 ATM port) port adapter

Not applicable

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-A3-E3—1-port E3 ATM, PCI-based port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T, 12.1(2)EC11

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-A3-T3—1-port T3 ATM, PCI-based port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

Not applicable

PA-A3-OC3MM—1-port OC-3c ATM, PCI-based multimode port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1

PA-A3-OC3SMI—1-port OC-3c ATM, PCI-based single-mode intermediate reach port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1

PA-A3-OC3SML—1-port OC-3c ATM, PCI-based single-mode long reach port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1

Packet-Over-SONET (POS)

PA-POS-OC3SML—1-port POS OC-3 single-mode, long reach port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1

PA-POS-OC3SMI—1-port OC3 single-mode, intermediate reach port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1

PA-POS-OC3MM—1-port POS OC3 multimode port adapter

12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1

12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1

Dynamic Packet Transport (DPT)

PA-SRP-OC12SML—2-port OC-12c Dynamic Packet Transport (DPT) long reach port adapter

Not applicable

12.0(7)SC, 12.1(2)EC1

12.0(7)SC

PA-SRP-OC12SM1—2-port OC-12c Dynamic Packet Transport (DPT) intermediate reach port adapter

Not applicable

12.0(7)SC, 12.1(2)EC1

12.0(7)SC

PA-SRP-OC12MM—2-port OC-12c Dynamic Packet Transport (DPT) multimode port adapter

Not applicable

12.0(7)SC

12.0(7)SC

¹To use a PA-4E 4-port Ethernet 10BaseT port adapter in a Cisco uBR7246 VXR, be sure you have the minimum required hardware revision (version 1.14, part number 800-02070-04) or a more recent version of the port adapter.
²To use a PA-8E 8-port Ethernet 10BaseT port adapter in a Cisco uBR7246 VXR, be sure you have the minimum required hardware revision (version 1.14, part number 800-02069-04) or a more recent version of the port adapter.
³The Gigabit Ethernet port adapter must be combined with the appropriate optical fiber cable and a Gigabit Interface Converter (GBIC). The Gigabit Ethernet port adapter is supported in Cisco IOS Release 12.0(8)SC1 and later versions of Cisco IOS Release 12.0 SC.
⁴To use a PA-H 1-port HSSI port adapter in a Cisco uBR7246 VXR, be sure you have the minimum required hardware revision (version 1.17, part number 800-02747-06) or a more recent version of the port adapter.
⁵To use a PA-2H 2-port HSSI port adapter in a Cisco uBR7246 VXR, be sure you have the minimum required hardware revision (version 1.3, part number 800-03306-02) or a more recent version of the port adapter.
⁶ CES = circuit emulation services.
⁷ CBR = constant bit rate.

Cisco Clock Card Release

The Cisco clock card is supported only on the Cisco uBR7246 VXR chassis, beginning with Cisco IOS Release 12.1(1a)T1. The clock card is not supported on the Cisco uBR7223 or the Cisco uBR7246.

Note The clock card works only with the MC16S or MC16E cable modem cards. The CM must also support the clocking mode.

ED Release	Additional Software Features¹ and MIBs²	Additional Hardware Features	Hardware Availability
12.1(3a) EC	New in Release 12.1(3a) EC: Hot-Standby 1+1 Redundancy Dynamic Upstream Modulation Cable Monitor Cable Interface Setup Facility Overlapping Subinterface IP Addresses	MC28 Cable Modem Card	10/00
12.1(3a) EC	Enhancements were made to the following MIBs: CISCO-DOCS-EXT-MIB DOC-IF-MIB
12.1(2) EC1	New in Release 12.1(2) EC1: MPLS³ VPN⁴ Support for Subinterfaces and Interface Bundles Dynamic Ranging Support Enhanced Per-Modem Error Counter Configurable Alternate Termination System Information Messages Internal Modem Configuration File Editor "max-cpe" CLI override	Port Adapters: Dynamic Packet Transport PA-SRP-OC12SML PA-SRP-OC12SMI PA-SRP-OC12MM PA-4E1G/120 PA-E3 PA-MC-4T1 PA-MC-8T1 PA-A3-T3 PA-A3-E3 PA-4T+ PA-8T-V35 PA-8T-X21	Now
12.1(2) EC1	New MIBs Supported: DOCSIS Ethernet MIB Objects Support (RFC⁵ 2665) DOCSIS OSSI⁶ Objects Support (RFC 2233) Multicast BPI⁷ MIB Support Link Up/Down Traps Support (RFC 2233) SNMP⁸ Cable Modem Remote Query SNMP Objects for Clear Host, Clear Cable Modem, and Show Current CPEs⁹

Image	Description
Two-Way Data/VoIP and Wireless Images
ubr7200-is-mz	IP routing and bridging, NAT, ISL, and VPN support
ubr7200-ik1s-mz	IP routing and bridging, baseline privacy, NAT, ISL, and VPN support
ubr7200-k1p-mz	IP routing with IS-IS, BGP, and baseline privacy (no bridging and no NAT)
ubr7200-p-mz	IP routing with IS-IS and BGP (no bridging and no NAT)
Telco Return Images
ubr7200-ik1st-mz	IP routing and bridging, baseline privacy, NAT, ISL, and DOCSIS telco return
ubr7200-ist-mz	IP routing and bridging, NAT, ISL, and DOCSIS telco return

Image	Description
Two-Way Data/VoIP Images
ubr7200-p-mz	IP routing and bridging, NAT, ISL, and VPN support
ubr7200-ps-mz	IP routing and bridging, baseline privacy, NAT, ISL, and VPN support
ubr7200-k1p-mz	IP routing with IS-IS, BGP, and baseline privacy (no bridging and no NAT)
ubr7200-k1ps-mz	IP routing with IS-IS and BGP (no bridging and no NAT)

Product Number	Cisco uBR7223	Cisco uBR7246	Cisco uBR7246 VXR
Ethernet
PA-4E—4-port Ethernet 10BaseT port adapter	11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(7)SC, 12.0(7)T, 12.1(1a)T1 ¹, 12.1(2)EC1
PA-8E—8-port Ethernet 10BaseT port adapter	11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(7)SC, 12.0(7)T, 12.1(1a)T1 ², 12.1(2)EC1
PA-FE-TX—1-port 100BaseTX Fast Ethernet port adapter	11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1
PA-FE-FX—1-port 100BaseFX Fast Ethernet port adapter	11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1
PA-2FEISL-TX—2-port 100BaseTX Fast Ethernet port adapter with Inter-Switch Link (ISL) support	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1
PA-2FEISL-FX—2-port 100BaseFX Fast Ethernet port adapter with Inter-Switch Link (ISL) support	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1
PA-12E/2FE—12-port 10BaseT and 2-port 10/100BaseTX port adapter	Not applicable	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
Gigabit Ethernet
PA-GE—1-port, full-duplex, IEEE 802.3z- compliant Gigabit Ethernet (GE) port adapter³	Not applicable	Not applicable	12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1
Serial
PA-4T+—4-port synchronous serial port adapter	11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(10)SC, 12.1(1a)T1
PA-8T-232—8-port EIA/TIA-232 synchronous serial port adapter	11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-8T-V35—8-port V.35 synchronous serial port adapter	11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-8T-X21—8-port X.21 synchronous serial port adapter	11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.1(2)EC1
PA-4E1G-75—4-port unbalanced (75-ohm) E1-G.703/G.704 synchronous serial port adapter	11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-4E1G-120—4-port balanced (120-ohm) E1-G.703/G.704 synchronous serial port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-E3—1-port high-speed serial E3 interface port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-T3—1-port T3 serial interface port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-2E3—2-port high-speed serial E3 interface port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-2T3—2-port T3 serial interface port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-MC-E3—1-port multi-channel E3, medium-speed serial interface port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-MC-T3—1-port T3 (channelized into 28 independent T1 data lines) port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-MC-4T1—4-port multichannel DS1 Integrated Services Digital Network (ISDN) Primary Rate Interface (PRI) single-wide port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-MC-8E1/120—8-port multichannel E1 Integrated Services Digital Network (ISDN) Primary Rate Interface (PRI) single-wide port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-MC-8T1—8-port multichannel DS1 Integrated Services Digital Network (ISDN) Primary Rate Interface (PRI) single-wide port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
HSSI
PA-H—1-port HSSI port adapter	11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(7)SC, 12.0(7)T, 12.1(1a)T1 ⁴, 12.1(2)EC1
PA-2H—2-port HSSI port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(7)SC, 12.0(7)T, 12.1(1a)T1 ⁵, 12.1(2)EC1
ATM
PA-A1-OC3SMI—1-port ATM OC-3c/STM-1 single-mode intermediate reach port adapter	11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-A1-OC3MM—1-port ATM OC-3c/STM-1 multimode port adapter	11.3(8)NA, 12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	11.3(8)NA, 12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-A2-4E1XC-OC3SM—5-port ATM CES⁶ (4 E1 120-ohm CBR⁷ ports and 1 OC-3 ATM single-mode port) port adapter	Not applicable	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-A2-4E1XC-E3ATM—5-port ATM CES⁶ (4 E1 120-ohm CBR⁷ ports and 1 E3 ATM port) port adapter	Not applicable	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-A2-4T1C-OC3SM—5-port ATM CES⁶ (4 T1 CBR⁷ ports and 1 OC-3 ATM single-mode port) port adapter	Not applicable	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-A2-4T1C-T3ATM—5-port ATM CES⁶ (4 T1 CBR⁷ ports and 1 T3 ATM port) port adapter	Not applicable	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-A3-E3—1-port E3 ATM, PCI-based port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T, 12.1(2)EC11	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-A3-T3—1-port T3 ATM, PCI-based port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	Not applicable
PA-A3-OC3MM—1-port OC-3c ATM, PCI-based multimode port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1
PA-A3-OC3SMI—1-port OC-3c ATM, PCI-based single-mode intermediate reach port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1
PA-A3-OC3SML—1-port OC-3c ATM, PCI-based single-mode long reach port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1
Packet-Over-SONET (POS)
PA-POS-OC3SML—1-port POS OC-3 single-mode, long reach port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1
PA-POS-OC3SMI—1-port OC3 single-mode, intermediate reach port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1
PA-POS-OC3MM—1-port POS OC3 multimode port adapter	12.0(5)T1, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(1)T, 12.0(6)SC, 12.1(1a)T1, 12.1(2)EC1	12.0(7)SC, 12.0(7)T, 12.1(1a)T1, 12.1(2)EC1
Dynamic Packet Transport (DPT)
PA-SRP-OC12SML—2-port OC-12c Dynamic Packet Transport (DPT) long reach port adapter	Not applicable	12.0(7)SC, 12.1(2)EC1	12.0(7)SC
PA-SRP-OC12SM1—2-port OC-12c Dynamic Packet Transport (DPT) intermediate reach port adapter	Not applicable	12.0(7)SC, 12.1(2)EC1	12.0(7)SC
PA-SRP-OC12MM—2-port OC-12c Dynamic Packet Transport (DPT) multimode port adapter	Not applicable	12.0(7)SC	12.0(7)SC

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Using Cisco CMTS Software