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This feature module describes the OC-12c Dynamic Packet Transport Port Adapter (DPT) feature.
This document includes the following sections:
The dual-width OC-12c Dynamic Packet Transport (DPT) port adapter is available on Cisco 7200 series routers and Cisco 7200 VXR series routers. The DPT is an OC-12c interface used in Cisco 7200 series and Cisco 7200 VXR routers to provide a shared IP over SONET capability.
The following benefits are offered by the DPT for the Cisco 7200 and Cisco 7200 VXR series routers:
For related information on this feature, refer to the following document:
The DPT is compatible with any Cisco 7200 series router equipped with the correct Route Switch Processor (RSP2 or RSP4), running Cisco IOS Release 12.0(6)S or later.
See the following sections for configuration tasks for the DPT interface. Each task in the list indicates if the task is optional or required.
For information on other configuration tasks for the DPT port adapter, refer to the "Configure an Ethernet" section in the "Configuring Interfaces" chapter of the Configuration Fundamentals Configuration Guide.
For information on other commands that can be used by the DP interface, refer to the Cisco IOS Release 12.0 configuration guides.
| Step | Command | Purpose | ||
|---|---|---|---|---|
| Router#show running-config | Confirms that the system recognizes the DPT. | ||
| Enables configuration mode. | |||
| Router#ip routing | Enables IP routing. | ||
| Router(config)#interface srp slot/port | Specify interface. Note The interface type of the DPT is SRP1. | ||
| Router(config-if)#ip address 192.168.2.3 255.0.0.0 | Assign an IP address and subnet mask to the interface. | ||
| Add any additional configuration subcommands required to enable routing protocols, and set the interface characteristics for your configuration requirements. |
| ||
| Router(config)# no shutdown | | ||
| Ctrl-Z | When you have included all the configuration subcommands to complete the configuration, press Ctrl-Z to exit configuration mode. | ||
| Router# copy running-config startup-config | Writes the new configuration to the start up configuration. |
| 1SRP= Spatial Reuse Protocol |
Step 1 Use the show running-config command to display the currently running configuration. The example below shows that the current software version is 12.0(6)S, a DPT is installed (the DPT is shown as interface SRP1/0), and the IP address of the DPT:
Router# show running-config Building configuration... Current configuration: version 12.0(6)S service timestamps debug uptime service timestamps log datetime no service password-encryption service udp-small-servers service tcp-small-servers ! hostname uut2 ! ip subnet-zero ip host abrick 192.168.254.254 ip host curly 192.168.1.20 ip host sink 192.168.1.30 ip host sneha 192.168.1.40 ip name-server 192.168.2.132 ! interface SRP1/0 mac-address 0010.5555.6666 ip address 192.168.0.20 255.255.255.0 no ip directed-broadcast no ip route-cache cef no ip route-cache distributed no keepalive no srp random-detect input high no srp random-detect input medium no srp random-detect input low
Step 2 Use the show version command to display the configuration of the system hardware and Cisco IOS software information. The following example shows that the Cisco IOS version is 12.0(6)S and a DPT is installed:
Router# show version Cisco Internetwork Operating System Software IOS (tm) 7200 Software (C7200-JS-M), Experimental Version 12.0(6)S(19990617:032053)] Copyright (c) 1986-1999 by cisco Systems, Inc. Compiled Thu 17-Jun-99 09:32 by karthiks Image text-base: 0x600088F8, data-base: 0x611F2000 ROM: System Bootstrap, Version 11.1(13)CA, EARLY DEPLOYMENT RELEASE SOFTWARE (f) BOOTFLASH: 7200 Software (C7200-BOOT-M), Version 11.3(2)AA, EARLY DEPLOYMENT, R) router uptime is 4 days, 16 minutes System returned to ROM by reload System image file is "tftp://223.255.254.254/muck/shirjosh/c7200-js-mz.Jun17" cisco 7206 (NPE200) processor with 122880K/8192K bytes of memory. R5000 CPU at 200Mhz, Implementation 35, Rev 2.1, 512KB L2 Cache 6 slot midplane, Version 1.3 Last reset from power-on Bridging software. X.25 software, Version 3.0.0. SuperLAT software (copyright 1990 by Meridian Technology Corp). TN3270 Emulation software. 8 Ethernet/IEEE 802.3 interface(s) 1 FastEthernet/IEEE 802.3 interface(s) 1 FDDI network interface(s) 1 SRP network interface(s) 125K bytes of non-volatile configuration memory. 4096K bytes of packet SRAM memory. 20480K bytes of Flash PCMCIA card at slot 0 (Sector size 128K). 4096K bytes of Flash internal SIMM (Sector size 256K). Configuration register is 0x0
The SRP interface uses ring architecture to provide redundancy and protection from a failed node or fiber cut through the use of Intelligent Protection Switching (IPS). The tasks described in this section are optional.
| Step | Command | Purpose | ||
|---|---|---|---|---|
| Router#configure terminal | Enables configuration mode. | ||
| Router(config)#interface srp slot/port | Configure an SRP interface. | ||
| Router(config-if)# srp ips request manual-switch a | Specifies an IPS manual switch on side A or side B. | ||
| Router(config-if)# srp ips wtr-timer 10 a | Specifies a wait-to-restore request (in seconds) to prevent switch oscillations on side A or side B. | ||
| Router(config-if)# srp ips timer 20 a | Configures a message timer to be sent to the inner and outer rings to control the frequency of IPS message transmissions on side A or side B. | ||
| Router(config-if)# ^Z | Exits back to EXEC mode so you can perform verification steps. |
Use the show srp command to determine whether an intelligent protection switch is enabled or idle:
Router1# show srp SRP 1/0
MAC Addresses
Side A (Outer ring RX) neighbour 0000.0000.0002
Side B (Inner ring RX) neighbour 0000.0000.0001
Node MAC address 0000.0000.0003
IPS State
Side A not wrapped
Side B not wrapped
Side A (Inner ring TX) IPS pkt. sent every 10 sec. (next pkt. after 6 sec.)
Side B (Outer ring TX) IPS pkt. sent every 10 sec. (next pkt. after 6 sec.)
IPS WTR period is 60 sec. (timer is inactive)
Node IPS State IDLE
IPS Self Detected Requests
Side A IDLE
Side B SF
IPS messages received
Side A (Outer ring RX) {0000.0000.0002,SF ,L,1024}
Side B (Inner ring RX) {0000.0000.0001,IDLE,S,1024}
IPS messages transmitted
Side A (Inner ring TX) {0000.0000.0003,SF ,L,1024}
Side B (Outer ring TX) {0000.0000.0003,SF ,S,1024}
Every node on a DPT ring maintains a topology map of the ring, so that it knows where to route traffic. It updates the topology map by periodically sending a query, called a topology discovery packet, out onto the ring. Each node on the ring adds its own MAC address to the packet. When the discovery packet returns to the originating node, the contents of the packet are used to update the topology map. You use the srp topology-timer command to set the frequency with which the node sends out topology discovery packets.
| Step | Command | Purpose | ||
|---|---|---|---|---|
| Router#configure terminal | Enables configuration mode. | ||
| Router(config)#interface srp slot/port | Configure an SRP interface. | ||
| router(config-if)#srp topology-timer 70 | Configures the frequency of the topology message timer in seconds. | ||
| router(config-if)#^Z | Exits back to EXEC mode so you can perform verification steps. | ||
| router#show srp topology | Confirm the identity of the nodes on the ring by entering the show srp topology command. The command output also shows the number of hops between nodes and identifies the nodes that are in wrap mode. |
Use the show srp topology command to show the identity of the nodes on the DPT ring according to their MAC addresses. The following example shows a three-node DPT ring.
Router# show srp topology
Topology Map for Interface SRP2/0
Topology pkt. sent every 61 sec. (next pkt. after 16 sec.)
Last received topology pkt. 00:00:45
Nodes on the ring:3
Hops (outer ring) Address
0 0000.0000.0001
1 0000.0000.0002
2 0000.0000.0003
This section provides the following configuration examples:
In the following example, the OC-12c DPT SRP interface is specified and the IP address and subnet mask is assigned to the interface.
Router(config)#interface srp 0/1 Router(config-if)#ip address 192.168.2.3 255.0.0.0
In the following example the SRP IPS options are configured:
Router(config)#interface srp slot/port srp ips request manual-switch a srp ips request forced-switch a srp ips wtr-timer 60 srp ips timer 90 a
In the following example, the identity of the nodes on the DPT ring according to their MAC addresses is shown. The following example shows a three-node DPT ring. Nodes 0 and 2 are wrapped:
Router#show srp topology
Topology Map for Interface SRP2/0
Topology pkt. sent every 61 sec. (next pkt. after 54 sec.)
Last received topology pkt. 00:00:07
Nodes on the ring:3
Hops (Outer ring) Address
0 0000.0000.0001 Wrapped
1 0000.0000.0002
2 0000.0000.0003 Wrapped
This section documents new commands. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command reference publications.
The SRP interface provides commands to enforce quality of service (QoS) functionality on the transmit side and receive side of Cisco routers. SRP uses the IP type of service (ToS) field values to determine packet priority.
On the transmit side the SRP interface classifies traffic into high- and low- priority traffic. High- priority traffic is rate shaped and has higher priority than low-priority traffic. The user has the option to configure high- or low-priority traffic and can rate limit the high-priority traffic.
To make adjustments to buffer settings on the receive side for different priority traffic, use the srp buffer-size interface configuration command. Use the no form of this command to disable buffer size configurations.
srp buffer-size receive [high | medium]
receive | Allocates synchronous dynamic random-access memory (SDRAM) buffer for incoming packets. |
high | medium | Buffer size for high- or medium-priority packets. Any number from 16 to 8192 in bytes. |
high = 4096 kbytes, medium = 4096 kbytes, low = 8192 kbytes
Interface configuration mode
| Release | Modification |
|---|---|
12.0(6)S | This command was introduced. |
The following example shows the buffer size for the receive side at the high setting of 17 kbytes:
router(config-if)# srp buffer-size receive high 17
| Command | Description |
mtu bytes | Adjusts the maximum packet size MTU size.1 |
srp deficit-round-robin | Sets SRP parameters. |
| 1MTU = maximum transmission unit |
To transfer packets from the internal receive buffer to IOS, use the srp deficit-round-robin configuration command. Use the no form of this command to disable srp deficit-round-robin.
srp deficit-round-robin [input | output] [quantum | deficit]
input | output | Either input or output is specified. |
high | medium | low | Priority queue level. |
quantum | DRR quantum value. Any number from 9216 to 32767. The default is 9216. |
deficit | DRR deficit value. Any number from 0 to 65535. The default is 16384. |
quantum = 9216, deficit = 16384
Configuration mode
| Release | Modification |
|---|---|
12.0(6)S | This command was first introduced. |
The following example shows packets configured for the high-priority input queue:
Router(config-if)# srp defict-round-robin input high deficit
| Command | Description |
srp priority-map receive | Enables classification of packets as high, medium, or low based on the IP TOS value |
srp buffer-size | Modifies the buffer space allocated for different priority traffic. By default high- and medium-priority packets get 4 MB of buffer space, and low-priority packets get 8 MB of buffer space. |
srp random-detect | Enables user to tune WRED parameters on packets received through the SRP interface. |
To loop the SRP interface on a OC-12c DPT, use the srp loopback interface configuration command. Use the no form of this command to remove the loopback.
srp loopback {internal | line} {a | b}
internal | line | Sets the loopback toward the network before going through the framer (internal), or loops the payload data toward the network (line). |
a | Loopback the A side of the interface (inner tx, outer rx) |
b | Loopback the B side of the interface (outer tx, inner rx). |
Disabled
Interface configuration
| Release | Modification |
|---|---|
12.0(6)S | This command was modified. |
Use this command for troubleshooting purposes.
The following example configures the loopback test on the a side of the SRP interface:
srp loopback line a
To set priority mapping for transmitting and receiving packets, use the srp priority-map configuration command. Use the no form of this command to disable priority mapping.
srp priority-map {receive} {high | medium | low}{transmit}{high | medium}
receive | transmit | Receiving or transmitting. |
high | medium | Mapping for high- or medium-priority packets. Range is between 1 and 8. |
low | Specifies mapping for low-priority packets on the receive side. |
receive high = 5, receive medium = 3, transmit = 7
Configuration mode
| Release | Modification |
|---|---|
12.0(6)S | This command was introduced. |
The SRP interface provides commands to enforce quality of service (QoS) functionality on the transmit side and receive side of Cisco routers. SRP uses the IP type of service (ToS) field values to determine packet priority.
The SRP interface classifies traffic on the transmit side into high- and low-priority traffic. High-priority traffic is rate shaped and has higher priority than low-priority traffic. You have the option to configure high- or low-priority traffic and can rate limit the high-priority traffic.
The command srp priority-map transmit enables the user to specify IP packets with <tos-value> and above to be considered as high-priority traffic.
On the receive side, when WRED is enabled, SRP hardware classifies packets into high-, medium-, and low-priority packets based on IP ToS value. After classification, it stores the packet into the internal receive buffer. The receive buffer is partitioned for each priority packet. Cisco routers can employ WRED based on the IP ToS value. Routers also employ the Deficit Round Robin (DRR) algorithm to transfer packets from the internal receive buffer to IOS.
The command srp priority-map receive enables the user to classify packets as high, medium, or low based on the IP ToS value.
The following example configures the Cisco 7200 series routers to transmit map priority frames with a 5 (high priority):
Router(config-if)# srp priority-map transmit
| Command | Description |
random detect | Configures WRED parameters on packets received through an SRP interface. |
To configure WRED parameters on packets received through an SRP interface, use the srp random-detect interface configuration command. Use the no form of this command to return the value to the default.
srp random-detect [enable | compute-interval | input | precedence]
compute-interval | Interval in the range of 1 to 128 nsec used to specify the queue depth compute interval. |
enable | Enable WRED |
input | WRED on packet input path. |
high | low | medium | Priority queue level. |
exponential-weight | Queue weight in bits. Any number from 0 to 6. |
precedence | Input queue precedence. |
128 seconds
Interface configuration command
| Release | Modification |
|---|---|
12.0(6)S | This command was introduced. |
The following example has configured WRED parameters on packets received through an SRP interface with a weight factor of 5:
Router(config-if)# srp random-detect input high exponential-weight 5
To disable the SRP interface, use the shutdown interface configuration command. To restart a disabled interface, use the no form of this command.
srp shutdown [a | b]
a | Specifies side A of the SRP interface. |
b | Specifies side B of the SRP interface. |
Enabled
Interface configuration
| Release | Modification |
|---|---|
12.0(6)S | This command was introduced. |
The shutdown command disables all functions on the specified interface.
This command also marks the interface as unavailable. To check whether an interface is disabled, use the EXEC command show interfaces. An interface that has been shut down is shown as administratively down in the display from this command.
The following example turns off the A side of the SRP interface:
srp shutdown a
| Command | Description |
show interfaces | Displays interfaces that are enabled. |
To limit the amount of high-priority traffic that the SRP interface can handle, use the srp tx-traffic-rate configuration command. Use the no form of this command to disable transmitted traffic rate.
srp tx-traffic number
number | The range in kilobits. The range is 1 to 65535. |
10 Mbps
Configuration mode
| Release | Modification |
|---|---|
12.0(6)S | This command was introduced. |
The following example shows SRP transmitted traffic transmitting at 1000 kilobits per second:
Router(config-if)# srp tx-traffic-rate 1000
DPT---Dynamic Packet Transport.
DRR---Deficit Round Robin.
IPS---Intelligent Protection Switching.
MAC---Media Access Control.
MTU---Maximum Transmission Unit.
QoS---Quality of Service.
RSP---Route Switch Processor.
SDRAM---Synchronous Dynamic Random-access Memory.
SONET---Synchronous Optical Network. An American National Standards Institute (ANSI) standard (T1.1051988) for optical digital transmission at hierarchical rates from 51.840 Mbps (OC-1) to 2.488 Gbps (OC-48) and higher.
SRP---Spatial Reuse Protocol. A Layer 2 MAC protocol for use with DPT, SONET, and SDH rings that runs over a dual-ring network topology and is characterized by shared media, statistical multiplexing, global fairness, and spatial reuse.
ToS---Type of Service.
WRED---Weighted Random Early Detection.
Posted: Fri Oct 1 13:53:31 PDT 1999
Copyright 1989-1999©Cisco Systems Inc.