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This chapter contains troubleshooting information. The chapter includes the following sections:
You can use a Cisco uBR924 cable access router to verify the downstream signal originating from a Cisco uBR7200 series universal broadband router. Be sure you configure the Cisco uBR924 according to DOCSIS cable modem practises. To verify the downstream signal from a Cisco uBR7200 series universal router using a Cisco uBR924, follow the procedure below:
Step 2 Scan the output for the value corresponding to the signal to noise (SNR) estimate variable. If this value is at least 35 dB, then you have an optimized signal. If the value is less than 34 dB, adjust the upconverter at the cable headend.
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Tips The SNR estimate for a cable modem installed at a headend should be between 35 dB and 39 dB. Although the exact value displayed will vary from cable modem to cable modem, values collected on the same cable modem from measurement to measurement will be consistent. Maximizing SNR optimizes cable modem reliability and service quality. |
To manage cable modems connected to the network, perform the following as appropriate:
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Caution Cisco recommends using default values for most commands. Default settings are adequate for most systems. |
| Command | Purpose |
|---|---|
CMTS01(config-if)#cable sync-interval msec | Specify the interval in milliseconds between successive sync message transmissions from the Cisco uBR7200 series. Valid values are from |
To verify whether or not a sync message interval is configured, enter the show running-config command and look for the cable interface configuration information. If the sync message interval is deactivated or reset to its default value, the no sync interval command line appears in the output.
The Cisco uBR7200 series can be configured to require all cable modems to return a known text string to register with the CMTS and gain access to the network. The text string can be from 1 to 80 characters in length. To activate cable modem authentication, use the following command from cable interface configuration mode.
| Command | Purpose |
|---|---|
CMTS01(config-if)# cable shared-secret [0|7] authorization-key | Enable cable modem authentication: 0 specifies an unencrypted authentication key; 7 specifies an encrypted authentication key. |
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Tips Be sure you enter the correct slot and port number in the cable interface configuration mode. Verify that the cable modem is using BPI and that it is assigned to a QoS with privacy active. Verify that the cable modem configuration file contains a matching key. |
To verify whether cable modem authentication is activated or deactivated, enter the command more system:running-config and look for the cable interface configuration information. If cable modem authentication is deactivated, it appears in this output as no cable secret-shared.
Cable modem upstream address verification ensures that only cable modems that have received DHCP leases through the Cisco uBR7200 series can access the HFC network. The Cisco uBR7200 series discards all packets received from or for hosts that have not received DHCP-assigned addresses.
| Command | Purpose |
|---|---|
CMTS01(config-if)# cable source-verify [dhcp] | Activate cable modem upstream verification. The dhcp option specifies that queries be sent to verify unknown IP addresses in upstream data packets. |
To verify whether cable modem upstream verification is activated or deactivated, enter the command more system:running-config and look for the no cable source-verify notation in the cable interface configuration information.
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Tips Be sure you enter the correct slot and port number when you enter the cable interface configuration mode. |
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Note If the Cisco uBR7200 series is reloaded or the ARP table is cleared, all hosts on the network will be forced to release and renew their IP addresses. Some systems may require restarting if the IP protocol stack is unable to renew using a broadcast IP address. |
The Cisco uBR7200 series universal broadband router software includes:
These algorithms control the capacity of the contention subchannel and how efficiently a given contention subchannel capacity is utilized.
In high contention mode, the Cisco uBR7200 series MAC scheduler uses collision statistics and sustains a high frequency of initial ranging slots until it detects a steady ranging state. The CMTS dynamically varies the frequency of initial ranging slots using the data grant utilization on the upstream channel(s). The CMTS trades upstream bandwidth between data grants and initial ranging slots. The CMTS auto-detects a high collision state and switches to low insertion interval mode after a steady state is achieved where few collisions occur.
The CMTS is careful when monitoring the ranging channel health to revert to a steady state. In steady state mode, data grants---grant utilization---receive preference over initial ranging slots.
Although the binary exponential backoff algorithm operates in a distributed fashion at different CMs, the CMTS provides centralized control for the backoff algorithm. To achieve this, it remotely monitors traffic load---the backlog developing on the contention channel---and then varies the backoff start and end specified in the MAPs for that upstream channel. This ensures colliding CMs are properly randomized in time.
The following cable interface commands are available to configure the dynamic contention algorithms:
[no] cable insertion-interval [automatic [<Imin [Imax]>]] | [<msecs>] [no] cable upstream <port num> range-backoff [automatic] | [<start> <end>] [no] cable upstream <port num> data-backoff [automatic] | [<start> <end>]
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Tips System defaults are to have dynamic ranging interval enabled, dynamic ranging backoff enabled, and fixed data backoffs for each upstream of a cable interface. |
The default automatic insertion interval setting enables the Cisco automatic initial ranging period algorithm where lower and upper default values of 50 msecs and 2 secs are used. The default automatic range-backoff enables the dynamic backoff algorithm.
| Command | Purpose |
|---|---|
CMTS01(config-if)# [no] cable insertion-interval automatic | Disable or enable the dynamic ranging interval algorithm. If lower and upper bounds for varying the period are not specified, the system uses default values of 50 msecs and 2 secs respectively. |
A CMTS administrator can enhance the upstream throughput from a cable modem connected to the Cisco uBR7200 series. The system employs a new algorithm that auto tunes the lookahead time in MAPs based on several input parameters for the corresponding upstream channel. The use of dynamic/optimal lookahead time in MAPs significantly improves the per-modem upstream throughput.
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Caution Only a trained CMTS administrator should adjust these values. |
To configure the dynamic map advance algorithm, use the following command in cable interface configuration mode.
| Command | Purpose |
|---|---|
CMTS01(config-if)#cable map-advance dynamic [<n>] | static | Specify a value to enhance the upstream throughput from a cable modem connected to the Cisco uBR7200 series. The <n> parameter provides the safety factor for the dynamic map advance algorithm. This parameter is specified in usecs and controls the amount of extra lookahead time in MAPs to account for inaccuracies of the measurement system and software latencies. The default value is 1000 usecs. You can vary this between 500 to 1500 usecs. This parameter is a delta value added to the dynamic map-advance that the algorithm computes. Using larger safety factors increases the run time lookahead in MAPs, but reduces the upstream performance. Use the static keyword for the map advance command. The Cisco uBR7200 series will use a fixed lookahead time in MAPs, regardless of the real propagation delay of the farthest cable modem on the network. This fixed lookahead time is computed based on the worst case parameters such as farthest DOCSIS propagation delay for the CMs. |
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Caution Cisco recommends if you are adjusting the dynamic map advance algorithm that you do not reduce the safety factor below the default value of 1000 usecs in a production network until you are confident that the reduced safety factor suffices for your deployment. The default value is chosen to be a safe operating point for the algorithm. |
You can configure the Cisco uBR7200 series to filter incoming packets from individual hosts or cable modems based on the source Media Access Controller (MAC) or Internet Protocol (IP) address. Definition of filters follows standard Cisco IOS configuration practices for access lists and groups.
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Note Configuring per modem or host filters is supported in Cisco IOS Release 12.0(5)T1 or higher, as well as in Cisco IOS Release 12.0(6)SC or higher. |
To configure per modem filters, use the following commands in cable interface configuration mode.
| Command | Purpose | ||
|---|---|---|---|
CMTS01(config-if)# cable {modem | host | device} {<macaddr><ipaddr> | } access group <acl> | Configure 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. Use modem if the device is a cable modem. Use host if the device is a CPE device attached to a cable modem. Define the filter to be applied to the device and a given address. The macaddr specifies the cable modem's or CPE device's unique MAC address. Use the ipaddr option to specify the CM or CPE device's current IP address. Use the acl option to assign the CM or CPE device to an access list. This defines the per-CM or per-host filter requirements implemented at the CMTS, rather than at the CM. Access list numbers are 1 to 99 for fast IP access lists, 100 to 199 for show extended IP access lists.
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Caution The system applies filters after the cable modem registers with the CMTS. Filter definitions are not saved across system reboots and must be applied each time a CM registers. |
The software supports traps to alert CMTS administrators on CMs going offline or back online. A typical registration and login procedure is shown below:
1. The CM registers with the Cisco uBR7200 series.
2. The Cisco uBR7200 series sends traps to management systems in use for the network.
3. The management system sets per modem filters using SNMP or rsh.
4. The user logs in at the server.
5. The login server obtains required modem and CPE information from the Cisco uBR7200 series.
6. The login server sets per-CPE filter in the Cisco uBR7200 series. The per-CPE filter overrides the per modem filter settings.
7. If the CM goes offline for a brief period of time, filters defined using the Cisco uBR7200 series remain active. If a CM stays offline for more than 24 hours, filter settings are reset.
8. If the user logs out or the login server detects that the user is not online, the login server sets default filters for the CM or the CPE device.
To specify the maximum number of hosts that can be attached to a subscriber's cable modem, use the following command in cable interface configuration mode.
| Command | Purpose |
|---|---|
CMTS01(config-if)# cable max-hosts n
| Specify the maximum number of hosts that can be attached to a cable modem on this interface. Valid range is from 0 to 255 hosts. Default = 0.
Reset the allowable number of hosts attached to a cable modem to the default value of 0 hosts. |
By default, registered cable modems that have no upstream activity for three minutes are timed out and disconnected from the Cisco uBR7200 series. This timeout interval can be decreased to 2 minutes or increased up to 60 minutes.
| Command | Purpose |
|---|---|
CMTS01(config-if)# cable registration-timeout n | Specify the maximum number of minutes allowed to elapse with no upstream activity before terminating the connection. Valid range is from 2 to 60 minutes. Default = 3 minutes. |
| Command | Purpose |
|---|---|
CMTS01(config-if)# clear cable modem mac-addr reset | Remove the cable modem with a specific MAC address from the station maintenance list and reset it. |
To verify whether or not the clear cable modem reset command has removed a cable modem from the station maintenance list and forced it to start a reset sequence, enter the show cable modem command.
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Tips Be sure you entered the correct cable modem IP address or MAC address when you typed the command. It might take up to 30 seconds for the cable modem to start the reset sequence. |
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Note This command is useful if an SNMP manager is not available, or if the cable modem is unable to obtain an IP address or respond to SNMP messages. |
| Command | Purpose |
|---|---|
CMTS01(config-if)# clear cable modem mac-addr counters | Clear the counters in the station maintenance list for the cable modem with a specific MAC address. |
To verify whether or not the counters in the Station Maintenance List are cleared, enter the following command. The station maintenance list counter will be 0.
To configure downstream rate limiting or shape downstream traffic, use the following command in cable interface configuration mode.
| Command | Purpose |
|---|---|
CMTS01(config-if)#[no] cable downstream rate-limit token-bucket [shaping] weighted-discard [expwt <n>] | Enables or disables rate limiting and traffic shaping on the downstream of a cable interface. |
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Note Using Cisco IOS Release 12.0(5)T1 or higher, the software adds downstream calendar queuing routines and grant shaping application of the calendar queues. |
Key command usage is elaborated below:
You can rate limit and shape traffic on a DOCSIS upstream channel. This 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 TCP/IP stack to pace the application traffic appropriately and approach throughput commensurate with the subscriber's defined QoS levels.
To configure this, use the following command in cable interface configuration mode.
| Command | Purpose |
|---|---|
CMTS01(config-if)#[no] cable upstream <n1> rate-limit [token-bucket] | Enables or disables DOCSIS rate limiting or shaping on an upstream channel. <n1> depends on the number of upstream channels on the specific cable modem card. |
Using Cisco IOS Release 12.0(5)T1 or higher, the software supports:
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Tips Upstream grant shaping is per CM (SID). Shaping can be enabled or disabled for the token-bucket algorithm. |
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Note Before the introduction of this feature, the CMTS would drop bandwidth requests from a CM it detected as exceeding its configured peak upstream rate. Such request dropping affects the throughput performance of IP-based protocols such as FTP, TCP, and SMTP. With this feature, the CMTS can shape (buffer) the grants for a CM that is exceeding its upstream rate, rather than dropping the bandwidth requests. |
CMTS01# show interface c3/0 sid 1 counters
Sid Inpackets Inoctets Outpackets Outoctets Ratelimit Ratelimit
BWReqDrop DSPktDrop
1 67859 99158800 67570 98734862 2579 0
The Cisco uBR7200 series software supports combined blind and time scheduled spectrum management using Cisco IOS Release 12.0(5)T1 images or higher:
With combined blind and time scheduled strategies, blind hop tables are given time-variant configurability. The frequency or subband list can change with time. Blind frequency hop is performed within the spectrum specified to be currently available. An example follows:
uBR(config)# cable spectrum-group 2 time Mon 09:00:00 frequency 10000000 uBR(config)# cable spectrum-group 2 time Tue 09:05:00 delete frequency 10000000 uBR(config)# cable spectrum-group 2 time Tue 09:00:00 frequency 5000000 uBR(config)# cable spectrum-group 4 time Fri 09:00:00 band 15000000 25000000 uBR(config)# cable spectrum-group 4 time Sat 09:00:00 delete band 15000000 25000000
Using guided frequency hop, the upstream channel frequency is reassigned if a threshold number or percentage of cable modems suddenly go offline. You can adjust the thresholds and assign explicit frequencies or frequency subbands and associated input power levels in the unified spectrum group table. The Cisco uBR7200 series locates the defined channel or a suitable channel and moves all cable modems on the upstream port.
The example below shows the Cisco uBR7200 series' ability to force the CTMS to change the upstream to another frequency before the CMTS sends a message to increase output power levels. You can configure the frequency hop table so that the next entry has the same frequency, but a different power level:
uBR(config)# cable spectrum-group 2 frequency 20000000 uBR(config)# cable spectrum-group 2 frequency 20000000 2 uBR(config)# cable spectrum-group 2 frequency 20000000 -2 uBR(config)# cable spectrum-group 2 frequency 22000000 uBR(config)# cable spectrum-group 2 frequency 22000000 2 uBR(config)# cable spectrum-group 2 frequency 22000000 3
The order of the configuration commands defines the order which frequency or power level is changed. There is always a single allocation set per-spectrum group, listing the currently available bands. In the case of a shared spectrum group, there is also a single free set and "in-use" set since there is a single RF domain. Otherwise, there are free and in-use sets for each upstream port since each upstream port has its own RF domain.
Sample output:
noisy1#show cable spec
Group Frequency Upstream Weekly Scheduled Power Shared
No. Band Port Availability Level Spectrum
(Mhz) From Time: To Time: (dBmV)
1 10.000- 0.000 1 No
1 11.000- 0.000 1 No
1 12.000- 0.000 1 No
1 13.000- 0.000 1 No
1 14.000- 0.000 1 No
2 10.000-15.000 2 No
2 10.208 [0.40] Cable3/0 U1 2
3 20.000- 0.000 3 Yes
3 21.000- 0.000 3 Yes
3 22.000- 0.000 3 Yes
3 23.000- 0.000 3 Yes
3 24.000- 0.000 3 Yes
3 0.400 [0.80] Cable3/0 U2 3
4 20.000-25.000 4 Yes
4 20.800 [1.60] Cable3/0 U3 4
5 10.000- 0.000 5 No
5 11.000- 0.000 5 No
5 12.000- 0.000 5 No
5 13.000- 0.000 Mon 17:06:00 --- --:--:-- 5 No
5 14.000- 0.000 Mon 17:08:00 --- --:--:-- 5 No
5 13.000- 0.000 Mon 17:10:00 --- --:--:-- 5 No
5 1.600 [3.20] Cable3/0 U4 5
6 10.000-13.000 6 No
6 13.000-15.000 Mon 17:11:00 Mon 17:12:00 6 No
6 10.800 [1.60] Cable3/0 U5 0
To display information about a specific interface or upstream port, enter the following command:show cable hop cable-if [upstream portnum]. Information lines describe the frequency hop status of an upstream port.
| Field | Description |
|---|---|
Upstream Port | The upstream port for this information line |
Port Status | Show "down" if frequency is unassigned, "admindown" if the port is shutdown, or the center frequency of the channel if the port is up |
Poll Rate | The rate station maintenance polls are generated (msec) |
Missed Poll Count | The number of missing polls |
Min Poll Sample | The number of polls in the sample |
Missed Poll Pcnt | The ratio of missing polls to the number of polls displayed as a percentage |
Hop Thres Pcnt | The level that the missed poll percentage must exceed to trigger a frequency hop expressed as a percentage |
Hop Period | The maximum rate which frequency hopping will occur (seconds) |
Corr FEC Errors | The number of correctable FEC errors on this upstream port |
Uncorr FEC Errors | The number of uncorrectable FEC errors on this upstream port |
Sample output:
noisy1#show cable hop
Upstream Port Poll Missed Min Missed Hop Hop Corr Uncorr
Port Status Rate Poll Poll Poll Thres Period FEC FEC
(ms) Count Sample Pcnt Pcnt (sec) Errors Errors
Cable3/0/U0 down 1000 * * * frequency not set * * * 0 0
Cable3/0/U1 admindown 1000 * * * interface is down * * * 0 0
Cable3/0/U2 admindown 1000 * * * interface is down * * * 0 0
Cable3/0/U3 admindown 1000 * * * interface is down * * * 0 0
Cable3/0/U4 admindown 1000 * * * interface is down * * * 0 0
Cable3/0/U5 admindown 1000 * * * interface is down * * * 0 0
Cable4/0/U0 10.800 Mhz 1000 0 0 ----- 100% 300 0 0
Cable6/0/U0 down 1000 * * * frequency not set * * * 0 0
To enable display of frequency hopping debugging messages, enter:
debug cable freqhop
To enable display of spectrum management debugging messages, enter:
debug cable specmgmt
This command also enables display of channel width list and offer list for the show cable spectrum-group command.
To force a frequency hop decision on the port or ports, enter:
test cable hop cable-if [upstream portnum]
Using Cisco IOS Release 12.0(5)T1 or higher headend images, you can use the following command to obtain specific upstream interface information:
show cable hop cable-if [upstream <portnum>]
| Field | Description |
|---|---|
Upstream Port | The upstream port for this information line |
Port Status | Show "down" if frequency is unassigned, "admindown" if the port is shutdown, or the center frequency of the channel if the port is up |
Poll Rate | The rate station maintenance polls are generated (msec) |
Missed Poll Count | The number of missing polls |
Min Poll Sample | The number of polls in the sample |
Missed Poll Pcnt | The ratio of missing polls to the number of polls expressed as a percentage |
Hop Thres Pcnt | The level that the missed poll percentage must exceed to trigger a frequency hop expressed as a percentage |
Hop Period | The maximum rate which frequency hopping will occur (seconds) |
Corr FEC Errors | The number of correctable FEC errors on this upstream port |
Uncorr FEC Errors | The number of uncorrectable FEC errors on this upstream port |
noisy1#show cable hop
Upstream Port Poll Missed Min Missed Hop Hop Corr Uncorr
Port Status Rate Poll Poll Poll Thres Period FEC FEC
(ms) Count Sample Pcnt Pcnt (sec) Errors Errors
Cable3/0/U0 down 1000 * * * frequency not set * * * 0 0
Cable3/0/U1 admindown 1000 * * * interface is down * * * 0 0
Cable3/0/U2 admindown 1000 * * * interface is down * * * 0 0
Cable3/0/U3 admindown 1000 * * * interface is down * * * 0 0
Cable3/0/U4 admindown 1000 * * * interface is down * * * 0 0
Cable3/0/U5 admindown 1000 * * * interface is down * * * 0 0
Cable4/0/U0 10.800 Mhz 1000 0 0 ----- 100% 300 0 0
Cable6/0/U0 down 1000 * * * frequency not set * * * 0 0
Using Cisco IOS Release 12.0(5)T1 or higher headend images, you can use the following command to obtain specific upstream interface information:
show cable hop cable-if [upstream <portnum>]
| Field | Description |
|---|---|
Upstream Port | The upstream port for this information line |
Port Status | Show "down" if frequency is unassigned, "admindown" if the port is shutdown, or the center frequency of the channel if the port is up |
Poll Rate | The rate station maintenance polls are generated (msec) |
Missed Poll Count | The number of missing polls |
Min Poll Sample | The number of polls in the sample |
Missed Poll Pcnt | The ratio of missing polls to the number of polls expressed as a percentage |
Hop Thres Pcnt | The level that the missed poll percentage must exceed to trigger a frequency hop expressed as a percentage |
Hop Period | The maximum rate at which frequency hopping will occur (seconds) |
Corr FEC Errors | The number of correctable FEC errors on this upstream port |
Uncorr FEC Errors | The number of uncorrectable FEC errors on this upstream port |
Sample output:
noisy1#show cable hop
Upstream Port Poll Missed Min Missed Hop Hop Corr Uncorr
Port Status Rate Poll Poll Poll Thres Period FEC FEC
(ms) Count Sample Pcnt Pcnt (sec) Errors Errors
Cable3/0/U0 down 1000 * * * frequency not set * * * 0 0
Cable3/0/U1 admindown 1000 * * * interface is down * * * 0 0
Cable3/0/U2 admindown 1000 * * * interface is down * * * 0 0
Cable3/0/U3 admindown 1000 * * * interface is down * * * 0 0
Cable3/0/U4 admindown 1000 * * * interface is down * * * 0 0
Cable3/0/U5 admindown 1000 * * * interface is down * * * 0 0
Cable4/0/U0 10.800 Mhz 1000 0 0 ----- 100% 300 0 0
Cable6/0/U0 down 1000 * * * frequency not set * * * 0 0
To enable display of frequency hopping debugging messages, enter:
debug cable freqhop
To enable display of spectrum management debugging messages, enter:
debug cable specmgmt
To force a frequency hop decision on the port or ports, enter:
test cable hop cable-if I portnum
Cisco IOS Release 12.0(7)XR2, Cisco IOS Release 12.1(1a)T1 or higher CMTS images, contain modem status enhancements. You can obtain operating statistics and determine the state of cable modems on the network.
The Cisco uBR7200 series supports polling of cable modems to obtain parameter and status information on an ongoing basis. Two new Cisco IOS commands are added to support the feature:
The Cisco uBR7200 series polls cable modems on the network and caches the state information on the CMTS, allowing administrators to use SNMP to manage the system.
This section describes how you can enable this. See the following configuration tasks:
| Command | Purpose |
|---|---|
Router(config)# snmp-server manager | Opens the SNMP manager |
Router(config)# snmp-server community [Community String] [Permissions] | Defines user permissions |
| Command | Purpose |
|---|---|
Router(config)# cable modem remote-query [polling interval] [Community string] | Specifies how often SNMP polls the modem and allows you to configure access |
To display information from a queried modem, enter the show cable modem remote-query command.
R7732-01-uBR7246#sh cable modem remote-query
IP address MAC address S/N US DS Tx Time Micro (dB) Modem
Ratio Power Power Offset Reflection State
5.108.1.2 0010.4bd7.ccf2 0.0 0.0 0.0 0 0 offline
5.109.1.2 0000.0000.0022 0.0 0.0 0.0 0 0 offline
5.110.1.2 0000.0000.0023 0.0 0.0 0.0 0 0 offline
5.108.1.5 0000.0000.0026 0.0 0.0 0.0 0 0 offline
5.108.1.4 0000.0000.0024 0.0 0.0 0.0 0 0 offline
5.108.1.3 0000.0000.0025 0.0 0.0 0.0 0 0 offline
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Tips To display debugging information, enter the debug cable remote-query command. |
See the following for an example debug message of a successful poll of a cable modem:
router# debug cable remote-query remote-query debugging is on . For IP address 209.165.200.223 Nov 10 15:56:50.241: docsIfSignalQualityEntry.5.4 = 380 Nov 10 15:56:50.241: docsIfMibObjects.2.2.1.3.2 = 360 Nov 10 15:56:50.245: docsIfDownstreamChannelEntry.6.4 = -30 Nov 10 15:56:50.245: docsIfUpstreamChannelEntry.6.3 = 12422 Nov 10 15:56:50.249: docsIfSignalQualityEntry.6.4 = 0 Nov 10 15:56:50.477:
See the following for an example debug message when the waiting queue at the CMTS is empty:
SNMP proxy exec got event, but queue is empty
See the following for an example debug message when you try to modify the polling interval or community string while polling in is progress:
Community string if modified will not be reflected
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Note The polling interval will be changed. To change the community string, you must unconfigure the snmp-server community command and reconfigure it with the new community string. |
Use the following show commands to gather status information about the specified modems.
| Command | Purpose |
|---|---|
Router# show cable flap-list | Displays statistics on the quality of the modem connection. |
Router# show cable modem | Displays statistics on modem states. |
Router# show cable modem remote-query | Displays statistics gathered by SNMP agents on modem states. |
Router# show interface cable | Displays statistics on the quality of the cable interface. |
Router# show interface cable sid | Displays statistics on the service IDs of the specified modems. |
Key show commands include:
Additional or changed show commands using Cisco IOS Release 12.0(7)XR2, Cisco IOS Release 12.1(1a)T1, or higher CMTS images include the following:
Using Cisco IOS Release 12.0(7)XR2, Cisco IOS Release 12.1(1a)T1 or higher, the show cable modem command includes all DOCSIS states, as well as other useful troubleshooting information such as last received upstream RF power level and maximum number of provisioned customer premises equipment.
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Note DOCSIS cable modems are required to pass through successive states during registration and provisioning. Using this information, you can isolate why a cable modem is offline or unavailable. |
Specific added information includes the downstream receive power ratio, downstream SNR, upstream and downstream power levels, transmit timing offset, and micro reflections in decibels.
For each upstream channel, you can obtain the following information:
See the sample command output below:
router# show cable modem
Interface Prim Online Timing Rec QoS CPE IP address MAC address
Sid State Offset Power
Cable3/0/U0 1 online 2257 0.00 3 0 10.30.128.142 0090.8330.0217
Cable3/0/U0 2 online 2262 *-0.50 3 0 10.30.128.145 0090.8330.020f
Cable3/0/U0 3 online 2260 0.25 3 0 10.30.128.146 0090.8330.0211
Cable3/0/U0 4 online 2256 *0.75 3 0 10.30.128.143 0090.8330.0216
Cable3/0/U0 5 online 2265 *0.50 3 0 10.30.128.140 0090.8330.0214
Cable3/0/U0 6 online 2256 0.00 3 0 10.30.128.141 0090.8330.0215
Cable3/0/U0 7 online 4138 !-1.00 3 1 10.30.128.182 0050.7366.124d
Cable3/0/U0 8 online 4142 !-3.25 3 1 10.30.128.164 0050.7366.1245
Cable3/0/U0 9 online 4141 !-3.00 3 1 10.30.128.185 0050.7366.17e3
Cable3/0/U0 10 online 4142 !-2.75 3 0 10.30.128.181 0050.7366.17ab
Cable3/0/U0 11 online 4142 !-3.25 3 1 10.30.128.169 0050.7366.17ef
The show cable modem indicates when the Cisco uBR7200 series router has detected an unstable return path for a particular CM and has compensated with a power adjustment. An asterisk appears in the power adjustment field for a CM when a power adjustment has been made; an exclamation point appears when the CM has reached its maximum power transmit level and cannot increase its power level any further.
Columns are described below:
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Note * means the noise power adjustment method is active for this modem; ! means the modem has reached its maximum transmit power |
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Note This parameter is only meaningful for cable modems. A CMTS will return a zero. |
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Note If the power level measurement is not supported, set this parameter to zero. Also, if the interface is down, this value will be the CMTS-configured value, the most current CM value, or zero. |
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Note The value is not assumed to return an absolutely accurate value, but gives a rough indication of microreflections received on this interface. |
See the following sample for detailed output of the show cable modem command:
router#show cable modem detail Interface SID MAC address Max CPE Concatenation Rx SNR Cable3/0/U0 1 0090.8330.0215 3 yes Cable3/0/U0 2 0090.8330.0213 3 yes Cable3/0/U0 3 0090.8330.0214 3 yes Cable3/0/U0 4 0090.8330.0217 3 yes Cable3/0/U0 5 0090.8330.020f 3 yes Cable3/0/U0 6 0050.7366.17e3 3 no Cable3/0/U0 7 0090.8330.0211 3 yes Cable3/0/U0 8 0050.7366.17af 3 no Cable3/0/U0 9 0090.8330.0216 3 yes Cable3/0/U0 10 0050.7366.1801 3 no Cable3/0/U0 11 0050.7366.124d 3 no Cable3/0/U0 12 0050.7366.1241 3 no Cable3/0/U0 13 0050.7366.17db 3 no Cable3/0/U0 14 0050.7366.1239 3 no Cable3/0/U0 15 0050.7366.17ab 3 no Cable4/0/U0 1 0050.7366.1db1 3 no 26.50 Cable4/0/U1 2 0050.7318.e97f 3 no 23.87 Cable4/0/U1 3 0050.7318.e965 3 no 23.85 Cable4/0/U0 4 0050.7318.e931 3 no 26.72 Cable4/0/U1 5 0050.7318.e92d 3 no 23.31 Cable4/0/U1 6 0050.7318.e97b 3 no 23.85 Cable4/0/U0 7 0050.7366.1d8d 3 no 26.88 Cable4/0/U0 8 0050.7318.e953 3 no 26.54 Cable4/0/U1 9 0050.7366.1d9d 3 no 23.72 Cable4/0/U1 10 0050.7318.e96b 3 no 23.79 Cable4/0/U1 11 0050.7366.1d95 3 no 23.82 Cable4/0/U0 12 0050.7318.e93f 3 no 26.26 Cable4/0/U1 13 0050.7318.e96d 3 no 23.51 Cable4/0/U0 14 0050.7318.e941 3 no 26.69 Cable4/0/U0 15 0050.7366.1dcd 3 no 26.94 Cable4/0/U1 16 0050.7318.e939 3 no 23.98 Cable4/0/U0 17 0050.7366.1d8f 3 no 27.13 Cable4/0/U0 18 0050.7302.3da3 3 no 26.58 Cable4/0/U0 19 0050.7318.e93b 3 no 26.49 Cable4/0/U0 20 0050.7318.e901 3 no 26.68 Cable4/0/U1 21 0050.7366.1dbb 3 no 23.45 Cable4/0/U0 22 0050.7318.e957 3 no 26.35 Cable4/0/U0 23 0050.7318.e985 3 no 26.40 Cable4/0/U0 24 0050.7366.1dbd 3 no 26.69
See the following sample output of modems connected on upstream channel 0 for cable interface slot 3, port 0:
router#show cable modem cable 3/0 upstream 0
Interface Prim Online Timing Rec QoS CPE IP address MAC address
Sid State Offset Power
Cable3/0/U0 1 offline 2264 -0.50 2 0 209.165.200.2 0090.8330.0214
Cable3/0/U0 2 offline 4137 !-3.50 2 0 209.165.200.9 0050.7366.17d3
Cable3/0/U0 3 init(d) 4136 !-2.50 2 0 209.165.200.0 0050.7366.17ab
Cable3/0/U0 4 init(d) 4138 !-4.75 2 0 209.165.200.0 0050.7366.1803
Cable3/0/U0 5 init(d) 4137 !-2.25 2 0 209.165.200.0 0050.7366.1801
Cable3/0/U0 6 init(o) 2251 -0.25 2 0 209.165.200.3 0090.8330.0213
Cable3/0/U0 7 offline 2264 0.75 2 0 209.165.200.4 0090.8330.020f
Cable3/0/U0 8 offline 2266 -0.50 2 0 209.165.200.5 0090.8330.0211
Cable3/0/U0 9 init(rc) 4662 1.00 2 0 209.165.200.0 00d0.bad3.c459
See the following sample output of unregistered modems connected on upstream channel 0 for cable interface 3, port 0:
router#show cable modem cable 3/0 upstream 0 unregistered
Interface Prim Online Timing Rec QoS CPE IP address MAC address
Sid State Offset Power
Cable3/0/U0 1 offline 2264 -0.50 2 0 209.165.200.2 0090.8330.0214
Cable3/0/U0 2 offline 4137 !-3.50 2 0 209.165.200.9 0050.7366.17d3
Cable3/0/U0 3 init(d) 4136 !-2.75 2 0 209.165.200.0 0050.7366.17ab
Cable3/0/U0 4 init(d) 4137 !-3.25 2 0 209.165.200.0 0050.7366.1803
Cable3/0/U0 5 init(d) 4141 !-2.75 2 0 209.165.200.0 0050.7366.1801
Cable3/0/U0 6 offline 2251 -0.25 2 0 209.165.200.3 0090.8330.0213
Cable3/0/U0 7 offline 2254 -1.00 2 0 209.165.200.4 0090.8330.020f
Cable3/0/U0 8 offline 2248 0.00 2 0 209.165.200.5 0090.8330.0211
Cable3/0/U0 9 init(rc) 4665 -0.50 2 0 209.165.200.0 00d0.bad3.c459
See the following sample output of offline modems connected on upstream channel 0 for cable interface 3, port 0:
router#show cable modem cable 3/0 upstream 0 offline
Interface MAC address Prim Previous Offline Rx Rx SM
Sid State Time Power SNR Exhaust
Count
Cable3/0/U0 0050.7366.17d3 2 init(o) Jan 16 20:30:26 !-3.50 ----- 1
Cable3/0/U0 0090.8330.0213 6 init(o) Jan 16 20:30:55 -0.25 ----- 181
Cable3/0/U0 0090.8330.020f 7 init(o) Jan 16 20:31:07 -1.00 ----- 181
Cable3/0/U0 0090.8330.0211 8 init(o) Jan 16 20:31:23 0.00 ----- 181
When a cable modem is detected to be offline by the CMTS---no reply after 16 retries of station maintenance requests---the cable modem is marked offline. Besides marking the cable modem and SID state offline, the SID is removed immediately from the CMTS ranging list and an aging timer is started to cleanup the SID completely if the cable modem does not attempt to come online within the next 24 hours.
Output fields are described below:
Following is a response to the show cable modem maintenance command using Cisco IOS Release 12.0(5)T1:
uBR7200#show cable modem maintenance
Interface SID MAC Address SM Exhausted SM Aborted
Count Time Count Time
Cable4/0/U1 1 0010.7b6b.5e27 4 Apr 29 19:33:19 0
Cable4/0/U0 2 0010.7b6b.5e15 8 Apr 29 19:34:55 0
Cable4/0/U2 11 0050.731c.b025 1 Apr 29 16:43:39 0
Cable4/0/U0 13 0050.731c.b021 1 Apr 29 15:58:43 0
Cable4/0/U0 16 0050.731c.b009 1 Apr 29 15:58:28 0
Cable4/0/U0 20 0050.731c.bfed 1 Apr 28 14:36:22 0
Cable4/0/U2 24 0050.731c.b023 1 Apr 27 10:30:36 0
Cable4/0/U1 27 0050.731c.bfeb 1 Apr 28 14:54:53 0
Cable4/0/U2 28 0050.731c.bfdf 1 Apr 28 14:50:55 0
Cable4/0/U1 30 0050.7366.1a71 2 Apr 29 17:49:00 0
Cable4/0/U1 31 0050.7366.1bab 3 Apr 29 16:21:47 0
Cable4/0/U1 32 0050.731c.bfe7 0 2 Jan 1 09:00:00
Cable4/0/U1 33 0050.731c.bfd3 4 Apr 29 15:09:28 0
Cable4/0/U2 35 0050.731c.b041 1 Apr 29 16:17:41 0
Cable4/0/U1 36 0050.7366.1ab9 2 Apr 29 16:53:26 0
See the following sample show interface cable command output for a cable modem located in slot 6/port 0 using the earlier Cisco IOS Release 12.1(5)T1 software:
router# show interface cable 6/0
Cable6/0 is up, line protocol is up
Hardware is BCM3210 FPGA, address is 00e0.1e5f.7a60 (bia 00e0.1e5f.7a60)
Internet address is 1.1.1.3/24
MTU 1500 bytes, BW 27000 Kbit, DLY 1000 usec, rely 255/255, load 1/255
Encapsulation, loopback not set, keepalive not set
ARP type: ARPA, ARP Timeout 04:00:00
Last input 4d07h, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
10908 packets input, 855000 bytes, 0 no buffer
Received 3699 broadcasts, 0 runts, 0 giants, 0 throttles
3 input errors, 3 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
5412 packets output, 646488 bytes, 0 underruns
0 output errors, 0 collisions, 13082 interface resets
0 output buffer failures, 0 output buffers swapped out
|
Note For more recent images such as Cisco IOS Release 12.1(1a)T1 or higher, the show interface upstream command is enhanced to display details on the MAC scheduler state for an upstream port. Refer to "Enhanced Show Interface Upstream Output" section. |
| Field | Description |
|---|---|
Cable slot/port is up/...administratively down | Indicates whether the interface hardware is currently active or taken down by the administrator |
line protocol is up/...administratively down | Indicates whether the software processes that handle the line protocol believe the interface is usable or if it has been taken down by the administrator |
hardware | Hardware type and address |
Internet address | Internet address followed by subnet mask |
MTU | Maximum Transmission Unit (MTU) of the interface |
BW | Bandwidth of the interface in kilobits per second |
DLY | Delay of the interface in microseconds |
rely | Reliability of the interface as a fraction of 255, calculated as an exponential average over 5 minutes. (For example, 255/255 is 100% reliability) |
load | Load on the interface as a fraction of 255, calculated as an exponential average over 5 minutes. (For example, 255/255 is complete saturation.) |
Encapsulation | Encapsulation method assigned to this interface. |
ARP type | Type of Address Resolution Protocol (ARP) and timeout value assigned |
Last input | Number of hours, minutes, and seconds since the last packet was successfully received by an interface |
output | Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface |
Last clearing of "show interface" counters | Time when the counters that measure cumulative statistics, such as number of bytes transmitted and received, were last reset to zero |
Queueing strategy | Displays the type of queueing configured for this interface. In the example output, the type of queueing configured is First In First Out (FIFO) |
Output queue | Number of packets in the output queue. The format of this number is A/B where A indicates the number of packets in the queue, and B indicates the maximum number of packets allowed in the queue |
drops | Indicates the number of packets dropped due to a full queue |
input queue/drops | Number of packets in the input queue. The format of this number is A/B where A indicates the number of packets in the queue, and B indicates the maximum number of packets allowed in the queue. |
drops | Indicates the number of packets dropped due to a full queue |
Five minute input rate | Average number of bits and packets transmitted per second in the last five minutes |
packets input | Total number of error-free packets received by the system |
bytes input | Total number of bytes, including data and MAC encapsulation, in the error-free packets received by the system |
no buffer | Number of received packets discarded because there was no buffer space in the main system |
Received broadcast | Total number of broadcast or multicast packets received by the interface |
runts | Number of packets that are discarded because they are smaller than the medium's minimum packet size |
giants | Number of packets that are discarded because they exceed the medium's maximum packet size |
input errors | Includes runts, giants, no buffers, CRC, frame, overrun, and ignored counts |
CRC | Indicates the number of times the cyclic redundancy checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received |
frame | Number of packets received incorrectly (with a CRC error and a non-integer number of octets) |
overrun | Number of times the receiver hardware was unable to forward received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data |
ignored | Number of received packets ignored by the interface because the interface hardware ran low on internal buffers |
packets output | Total number of messages transmitted by the system |
bytes | Total number of bytes, including data and MAC encapsulation, transmitted by the system |
underruns | Number of times the transmitter ran faster than the receiving device could handle |
output errors | Sum of all errors that prevented the final transmission of packets out of the interface being examined |
interface resets | Number of times an interface has been completely reset |
output buffer failures | Number of times the output buffer has failed |
output buffer swapped out | Number of times the output buffer has been swapped out |
See the following sample output for the downstream cable interface of slot 6 on port 0 from the show interface cable downstream command:
router# show interface cable 6/0 downstream
Cable6/0: Downstream is up
111947771 packets output, 1579682655 bytes, 0 discarded
0 output errors
| Field | Description |
|---|---|
Cable | Indicates the location of the downstream interface. |
Downstream is up/...administratively down | Indicates the administrative state of the interface. |
packets output | Total number of packets transmitted out of this interface. |
bytes | Total number of bytes transmitted out of this interface |
discarded | Total number of packets discarded |
output errors | Sum of all errors that prevented downstream transmission of packets out of this interface |
See the following sample output for the upstream cable interface located in slot 3/port 0 from the show interface cable upstream command:
router# show interface cable 3/0 upstream 0
Cable3/0: Upstream 0 is up
Received 16873 broadcasts, 0 multicasts, 73310 unicasts
0 discards, 89053 errors, 0 unknown protocol
90183 packets input, 1 uncorrectable
89042 noise, 0 microreflections
Total Modems On This Upstream Channel : 8 (4 active)
Default MAC scheduler
Queue[Rng Polls] 0/20, fifo queueing, 0 drops
Queue[Cont Mslots] 0/104, fifo queueing, 0 drops
Queue[CIR Grants] 0/20, fair queueing, 0 drops
Queue[BE Grants] 0/30, fair queueing, 0 drops
Queue[Grant Shpr] 0/30, calendar queueing, 0 drops
Reserved slot table currently has 0 CBR entries
Req IEs 134469315, Req/Data IEs 0
Init Mtn IEs 385879, Stn Mtn IEs 131059
Long Grant IEs 10766, Short Grant IEs 15895
Avg upstream channel utilization : 1%
Avg percent contention slots : 97%
Avg percent initial ranging slots : 0%
Avg percent minislots lost on late MAPs : 0%
Total channel bw reserved 0 bps
CIR admission control not enforced
Current minislot count : 6676390 Flag: 0
Scheduled minislot count : 6676545 Flag: 0
Table 4-18 describes the fields shown in the show interface cable upstream display.
| Field | Description |
|---|---|
Cable | Indicates the location of the upstream interface |
Upstream is up/...administratively down | Indicates the administrative state of the upstream interface |
Received broadcasts | Number of broadcast packets received through this upstream interface |
multicasts | Number of multicast packets received through this upstream interface |
unicasts | Number of unicast packets received through this interface |
discards | Number of packets discarded by this interface |
errors | Sum of all errors that prevented upstream transmission of packets through this interface |
unknown protocol | Number of packets received that were generated using a protocol unknown to the Cisco uBR7246 |
packets input | Number of packets received through this upstream interface that were free from errors |
corrected | Number of error packets received through this upstream interface that were corrected |
uncorrectable | Number of error packets received through this upstream interface that could not be corrected |
noise | Number of upstream packets corrupted by line noise |
microreflections | Number of upstream packets corrupted by microreflections |
Guaranteed-rate service queue depth | Number of bandwidth requests queued up in the Guarantee-rate queue. This queue is only available to modems that have a reserved minimum upstream rate in their Class of Service |
Best-effort service queue depth | Number of bandwidth requests queued up in the Best-effort queue. This queue is available to all modems that do not have any reserved rate on the upstream |
Total Modems On This Upstream Channel | Number of cable modems currently sharing this upstream channel. This field also shows how many of these modems are active |
Current Total Bandwidth Reserved | Total amount of bandwidth reserved by all modems sharing this upstream channel that require bandwidth reservation. The Class of Service for these modems specifies some non-zero value for the guaranteed-upstream rate. When one of these modems is admitted on the upstream, this field value is incremented by this guaranteed-upstream rate value |
CIR admission control (formerly: Current Admission Control Status) | Indicates the status of admission control on the upstream channel ENFORCED status allows users to enable admission control on a per port basis. This controls how limited bandwidth is allocated. NOT ENFORCED status indicates that there is no admission control. Every modem that registers with a class of service specifying a minimum upstream rate will be admitted by the CMTS regardless of how much aggregate bandwidth is actually available. Users enable admission control by using the admission control CLI |
Default MAC scheduler | Indicates the status of the MAC scheduler as being in default mode as opposed to Automated Test Procedure (ATP) |
Queue[Rng Polls] | The MAC scheduler queue showing the number of ranging polls |
Queue[Cont Mslos] | The MAC scheduler queue showing the number of forced contention request slots in MAPS |
Queue[CIR Grants] | The MAC scheduler queue showing the number of CIR grants pending |
Queue[BE Grants] | The MAC scheduler queue showing the number of BE grants pending |
Queue[Grant Shpr] | The MAC scheduler queue showing the number of grants that have been buffered for traffic shaping |
drops | Number of packets dropped |
Reserved slot table currently has 0 CBR entries | Number of CBR sessions active on an upstream channel at any given time |
Req IEs | The running counter of request IEs sent in MAPS |
Req/Data IEs | The counter of request/data IEs sent in MAPS |
Init Mtn IEs | The counter of Initial Maintenance IEs |
Stn Mtn IEs | Number of station maintenance (ranging poll) IEs |
Long Grant IEs | Number of long grant IEs |
Short Grant IEs | Number of short grant IEs |
Avg upstream channel utilization | Indicates on average what percent of the upstream channel bandwidth is being used |
Avg percent contention slots | Indicates on average what percent of slots are in contention state |
Avg percent initial ranging slots | Indicates on average what percent of slots are in initial ranging state |
Avg percent minislots lost on late MAPs | Indicates on average what percent of slots are lost because a MAP interrupt was too late |
Current minislot count (formerly: Last Minislot Stamp (current_time_base)) | Indicates the current minislot count at the CMTS. FLAG indicates the timebase reference. This field is used only by developers. |
Scheduled minislot count (formerly: Last Minislot Stamp (scheduler_time_base)) | Indicates the furthest minislot count allocated at the indicated time. FLAG indicates the timebase reference. This field is used only by developers. |
The show interface cable upstream command is enhanced in Cisco IOS Release 12.0(7)XR2, Cisco IOS Release 12.1(1a)T1, or higher CMTS images to display detailed MAC scheduler state information for the upstream port. The example below illustrates the new display:
cmts#show interface cable 3/0 upstream 0
Cable3/0:Upstream 0 is up
Received 13 broadcasts, 0 multicasts, 110 unicasts
0 discards, 106 errors, 0 unknown protocol
123 packets input, 0 uncorrectable
106 noise, 0 microreflections
Total Modems On This Upstream Channel :3 (3 active)
Default MAC scheduler
Queue[Rng Polls] 0/20, fifo queueing, 0 drops
Queue[Cont Mslots] 0/104, fifo queueing, 0 drops
Queue[CIR Grants] 0/20, fair queueing, 0 drops
Queue[BE Grants] 0/30, fair queueing, 0 drops
Queue[Grant Shpr] 0/30, calendar queueing, 0 drops
Reserved slot table currently has 2 CBR entries
Req IEs 280185, Req/Data IEs 0
Init Mtn IEs 800, Stn Mtn IEs 49
Long Grant IEs 26, Short Grant IEs 15
Avg upstream channel utilization :1%
Avg percent contention slots :97%
Avg percent initial ranging slots :1%
Avg percent minislots lost on late MAPs :0%
Total channel bw reserved 192000 bps
CIR admission control not enforced
Current minislot count :1165412 Flag:1
Scheduled minislot count :1176227 Flag:1
New items in the display include:
To display per-SID counters for bandwidth requests, use the show interface cable privileged EXEC command: show interface cable interface sid [sid] counters verbose. Data transport over the RF link uses the registered SID address, rather than the Ethernet address. This allows multiple hosts to access the network by using a single cable modem.
|
Note Cisco IOS Release 12.0(7)XR2 and 12.1(1a)T1 adds the verbose option to provide SID details. |
See the following display output for the verbose keyword extension for SID 1 on interface cable slot 3, port 0:
router# show interface c3/0 sid 1 counters verbose Sid : 1 Input packets : 39 Input octets : 15964 Output packets : 30 Output octets : 8796 BW requests received : 40 Grants issued : 40 Rate exceeded BW request drops : 0 Rate exceeded DS packet drops : 0
See the following display output for the verbose keyword extension for all SIDs on the specified interface:
router# show interface c3/0 sid counters verbose Sid : 1 Input packets : 39 Input octets : 15964 Output packets : 30 Output octets : 8796 BW requests received : 40 Grants issued : 40 Rate exceeded BW request drops : 0 Rate exceeded DS packet drops : 0 Sid : 2 Input packets : 0 Input octets : 0 Output packets : 0 Output octets : 0 BW requests received : 0 Grants issued : 0 Rate exceeded BW request drops : 0 Rate exceeded DS packet drops : 0 Sid : 3 Input packets : 0 Input octets : 0 Output packets : 0 Output octets : 0 BW requests received : 0 Grants issued : 0 Rate exceeded BW request drops : 0 Rate exceeded DS packet drops : 0
See the following display for the SIDs connected to the specified interface:
Lab-CMTS# show inter cab 3/0 sid
Sid Prim Type Online Admin QoS Create IP Address MAC Address
Sid State Status Time
23 stat init(d) enable 2 04:00:54 209.165.200.0 0050.7366.17ab
24 stat init(d) enable 2 04:00:58 209.165.200.0 0050.7366.1803
25 stat init(rc) enable 2 04:01:05 209.165.200.0 00d0.bad3.c459
26 stat init(d) enable 2 04:01:10 209.165.200.0 0050.7366.1801
27 stat offline enable 2 04:01:31 209.165.200.225 0090.8330.0213
28 stat offline enable 2 04:01:59 209.165.200.226 0090.8330.0211
29 stat offline enable 2 04:02:07 209.165.200.227 0090.8330.0214
30 dyn init(o) enable 2 04:03:09 209.165.200.228 0090.833
See the following connection information for all SIDs on the specified interface:
router# show interface c3/0 sid connectivity
Sid 1st time Times %online Online time Offline time
online Online min avg max min avg max
1 15:37:24 1 99.73 00:00 1h45m 1h45m 00:17 00:17 00:17
2 15:37:24 1 99.73 00:00 1h45m 1h45m 00:17 00:17 00:17
3 15:37:24 1 99.73 00:00 1h45m 1h45m 00:17 00:17 00:17
See the following connection information for SID 1 on the specified interface:
router# show interface c3/0 sid 1 connectivity
Sid 1st time Times %online Online time Offline time
online Online min avg max min avg max
1 15:37:24 1 99.72 00:00 1h41m 1h41m 00:17 00:17 00:17
See the following display for the counters of the SIDs connected to the specified interface:
router# show interface c3/0 sid counters
Sid Inpackets Inoctets Outpackets Outoctets Ratelimit Ratelimit
BWReqDrop DSPktDrop
1 40 16586 31 9160 0 0
2 0 0 0 0 0 0
3 0 0 0 0 0 0
See the following display for the counters of SID 1 on the specified interface:
router# show interface c3/0 sid 1 counters
Sid Inpackets Inoctets Outpackets Outoctets Ratelimit Ratelimit
BWReqDrop DSPktDrop
1 39 15964 30 8796 0 0
Table 4-19 describes the fields shown in the output for the show interface cable sid displays.
| Field | Description |
|---|---|
Sid | Service identification number |
Prim Sid | The primary service identifier assigned to the modem |
Type | Indicates this SID was created statically at the time of registration or dynamically by the exchange of dynamic service messages between the CM and CMTS |
Online State | "Online" means the modem owning this SID is processing traffic. "Offline" means the modem owning this SID is not processing traffic |
Admin Status | "Disable" means that the SID has been turned off. "Enable" is the normal state |
QoS | Quality of service. |
Create time | When the SID was created, number of seconds since the system booted |
Input octets (Inoctets) | Number of octets received by using this SID |
Input packets (Inpackets) | Number of packets received by using this SID |
Output octets (Outoctets) | Number of octets sent from this SID |
Output packets (Outpackets) | Number of packets sent from this SID |
IP address | IP address of the modem owning this SID |
MAC address | MAC address of the modem owning this SID |
BW requests received | Number of bandwidth requests received by this SID |
Grants issued | Number of bandwidth requests granted by this SID |
Rate exceeded BW request drops | Number of bandwidth requests not granted by this SID |
Rate exceeded DS packet drops | Number of downstream packets lost by this SID |
Ratelimit BWReqDrop | Number of bandwidth requests not granted by this SID |
Ratelimit DSPktDrop | Number of downstream packets lost by this SID |
1st time online | Time at which the modem with this SID connected |
Times online | Number of times the modem with this SID has connected |
% online | Percentage of time the modem with this SID has been connected |
Online time | The minimum, average, and maximum number of hours and minutes the modem with this SID has been connected |
Offline time | The minimum, average, and maximum number of hours and minutes the modem with this SID has been disconnected |
Following is a response to the show cable qos profile command. The display shows ToS specifications:
uBR7200#show cable qos profile Service Prio Max Guarantee Max Max tx TOS TOS Create B class upstream upstream downstream burst mask value by priv > bandwidth bandwidth bandwidth enab 1 0 0 0 0 0 0x0 0x0 cmts(r) no 2 0 64000 0 1000000 0 0x0 0x0 cmts (r) no 3 0 1000 0 1000 0 0x0 0x0 cmts no 4 3 256000 0 512000 0 0x0 0x0 cm no 5 5 1000000 0 10000000 0 0x0 0x0 cm no 6 3 256000 0 512000 0 0x0 0x0 cm yes
|
Note The "r" in the "Create by" column means the first two classes of service the CMTS creates are reserved for CMs that are not online. |
Displays upstream packet discards, errors, error-free packets, correctable and uncorrectable errors, noise and microreflection statistics:
show interface slot/downstream-port upstream
|
Note Although this is a Cisco proprietary CMTS feature, it is compatible with all DOCSIS-compliant cable modems. Unlike SNMP, the flap list uses zero bandwidth. |
The flap list collects the following station maintenance statistics:
The cable system administrator typically:
These reports can be given to the Customer Service Department or the cable plant's Operations and Maintenance Department. Using these reports, maintenance personnel can quickly discern how characteristic patterns of flapping cable modems, street addresses, and flap statistics can indicate which amplifier or feeder lines are faulty. The reports also help you quickly discern whether problems exist in your downstream or upstream path, and whether the problem is ingress noise or equipment related.
Default values for the following flap-list configuration commands are:
|
Note Since the cable flap list was originally developed, polling mechanisms have been enhanced since Cisco IOS Release 11.3.7 NA to have an increased rate of 1/sec when polls are missed. Cable modems go offline faster than the frequency hop period. This can cause the frequency to stay fixed while cable modems go offline. To compensate for this, as appropriate, you can reduce the hop period to 10 seconds. |
|
Tips In Cisco IOS Release 12.0(7)XR2 , Cisco IOS Release 12.1(1a)T1, and higher, the system supports automatic power adjustments. The show cable flap-list and show cable modem commands now indicate when the Cisco uBR7200 series router 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. |
The following tips and scenarios allow you to use the flap list in the most effective way:
Following is a sample response to the show cable flap command:
uBR7200#show cable flap Mac Addr CableIF Ins Hit Miss CRC P-Adj Flap Time 0010.9500.461f C3/0 U1 56 18857 887 0 1 116 Jun 1 14:09:12 0010.9500.446e C3/0 U1 38 18686 2935 0 1 80 Jun 2 19:03:57 0010.9500.38ec C3/0 U2 63 18932 1040 0 8 138 Jun 2 23:50:53 0010.9500.4474 C3/0 U2 65 18913 1053 0 3 137 Jun 2 09:30:09 0010.9500.4672 C3/0 U2 56 18990 2327 0 6 124 Jun 2 10:44:14 0010.9500.38f0 C3/0 U2 50 18964 2083 0 5 111 Jun 2 20:46:56 0010.9500.e8cb C3/0 U2 0 6537 183 0 1 5 Jun 2 22:35:48 0010.9500.38f6 C3/0 U3 50 19016 2511 0 2 104 Jun 2 07:46:31 0010.9500.4671 C3/0 U4 43 18755 3212 1 1 89 Jun 1 19:36:20 0010.9500.38eb C4/0 U0 57 36133 1608 0 6 126 Jun 2 20:04:58 0010.9500.3ce2 C4/0 U0 44 35315 1907 0 4 99 Jun 2 16:42:47 0010.9500.e8d0 C4/0 U2 0 13213 246 0 1 5 Jun 3 04:15:30 0010.9500.4674 C4/0 U4 56 36037 2379 0 4 121 Jun 3 00:34:12 0010.9500.4677 C4/0 U4 40 35781 2381 0 4 91 Jun 2 12:14:38
0010.9500.4614 C5/0 U5 40 21810 2362 0 502 586 Jun 2 21:43:02 0010.9500.3be9 C6/0 U5 63 22862 969 0 0 128 Jun 1 14:09:03 0010.9500.4609 C6/0 U5 55 22723 2127 0 0 112 Jun 1 14:08:02 0010.9500.3cb8 C6/0 U5 49 22607 1378 0 0 102 Jun 1 14:08:58 0010.9500.460d C6/0 U5 46 22477 2967 0 2 96 Jun 2 17:03:48 0010.9500.3cba C6/0 U5 39 22343 3058 0 0 81 Jun 1 14:13:16 0010.9500.3cb4 C6/0 U5 38 22238 2936 0 0 79 Jun 1 14:09:26 0010.9500.4612 C6/0 U5 38 22306 2928 0 0 79 Jun 1 14:09:29
The command line with an arrow next to it reveals a cable modem that is continuously flapping. A high flap rate indicates that the cable modem is power adjusting frequently. This can indicate a problem with an amplifier. The number reveals the number of times the CMTS instructed the cable modem to adjust the transmit power more than 3 dB.
Cable modems are automatically added to the flap list when any of the following conditions are detected:
The flap list can be queried either using the standard Simple Network Management (SNMP) API or the CLI. Using any third party SNMP Management Information Base (MIB) browser, you can query the ccsFlapTable in the CISCO-CABLE-SPECTRUM-MIB, a proprietary extension to the DOCSIS MIBs.
Using the show cable flap list command, the flap list statistics are accessed. A sample appears below. Each of the columns in the display are described in Table 4-20:
MAC ID___ CableIF Ins _Hit__ Miss CRC P-Adj Flap ___Time____ 0010.7b6b.60ad C3/0 U0 0 14386 1390 1 38 41 Nov 24 21:34:24 0010.7b6b.65a3 C3/0 U0 0 14503 1264 1 33 37 Nov 24 21:28:09 0010.7b6b.6b9d C3/0 U0 0 14060 1726 3 40 43 Nov 24 21:18:36
| Statistic | Description |
MAC ID | This is the MAC-layer address of a cable modem. The first six digits indicate the vendor ID of the cable modem manufacturer, followed by six digits indicating a unique host address. Each cable modem's MAC address is unique. |
Cable IF | This is the physical upstream interface on the Cisco uBR7200. It denotes the cable modem card slot number, the downstream port number on the RF line card and the upstream port number on the same cable modem card. The flap list data can be sorted based on the upstream port number which is useful when isolating reverse path problems unique to certain combining groups. |
Insertions | Link insertion is the process whereby a modem performs an initial maintenance procedure to establish link with the CMTS. The Ins column is the flapping modem's insertion count and indicates the number of times the RF link was abnormally re-established. An abnormality is detected when the time between link re-establishment attempts is less than the user-configurable parameter. Normal modem activity follows the sequence below.
When the link is broken, initial maintenance is repeated to re-establish the link. Initial maintenance @ Time T1 Station maintenance Init maintenance @ Time T2 The Ins and Flap counters in the flap list are incremented whenever T2 - T1 < N where N is the insertion-time parameter configured in <cable flap-list insertion-time>. Default value for this parameter is TBD seconds. A high Ins number indicates:
|
Hit and Miss | The HIT and MISS columns are keepalive polling statistics between the Cisco uBR7200 series and the cable modem. The station maintenance process occurs for every modem approximately every 25 seconds. When the CMTS receives a response from the modem, the event is counted as a Hit. If the CMTS does not receive a response from the cable modem, the event is counted as a Miss. A cable modem will fail to respond either because of noise or if it is down. Modems which only log Misses and zero Hits are assumed to be powered off. Misses are not desirable since this is usually an indication of a return path problem; however, having a small number of misses is normal. The flap count is incremented if there are M consecutive misses where M is configured in the cable flap miss-threshold parameter. The parameter value ranges from 1 to 12 with a default of 6. Ideally, the HIT count should be much greater than the Miss counts. If a modem has a HIT count much less than its MISS count, then registration is failing. Noisy links cause the MISS/HIT ratio to deviate from a nominal 1% or less. High Miss counts can indicate:
|
Cyclical Redundancy Check (CRC) | This statistic tracks the CRC error counter per modem. CRC errors are usually an indication of noise on a plant. A low count can be always be expected but a high CRC number calls for some the plant troubleshooting. The CRC counter indicates:
|
Power Adjustments (P-Adj) | The station maintenance poll in the CMTS constantly adjusts the modem transmit power, frequency, and timing. The P-Adj column indicates the number of times the modem's power adjustment exceeded the threshold value. The power adjustment threshold may be set using the <cable flap power threshold > parameter with a value range of 0 to 10 dB and a default value of 2 dB. Tuning this threshold is recommended to decrease irrelevant entries in the flap list. Power Adjustment values of 2 dB and below will continuously increment the P-Adj counter. The modem transmitter step size is 1.5 dB, whereas the headend may command 0.25 dB step sizes. Power adjustment flap strongly suggests upstream plant problems such as:
|
Flap | The Flap counter indicates the number of times the modem has flapped. This counter is incremented when one of the following events is detected: Unusual modem insertion or reregistration attempts. The Flap and the Ins counters are incremented when the modem tries to reestablish the RF link with the CMTS within a period of time that is less than the user-configurable insertion interval value. Abnormal Miss/Hit ratio The Flap counter is incremented when N consecutive Misses are detected after a Hit where N can be user-configurable with a default value of 6. Unusual power adjustment The Flap and P-adj counters are incremented when the modem's upstream power is adjusted beyond a user-configurable power level. |
Time | Time is the timestamp indicating the last time the modem flapped. The value is based on the clock configured on the local Cisco uBR7200 series. If no time is configured, this value is based on the current uptime of the Cisco uBR7200 series. When a modem meets one of the three flap list criteria, the Flap counter is incremented and Time is set to the current time. |
This section includes suggestions on how to interpret different network conditions based on the flap list statistics:
You can specify the number of days to record and retain flapping activity on cable modems currently in the flap-list table. This value is known as the age of the flap list. The valid range is from 1 to 60 days.
To set the age of the flap list, use the following command in global configuration mode.
| Command | Purpose |
|---|---|
CMTS01(config)# cable flap-list aging days | Specify the number of days to record and retain flapping activity for the cable modems connected to this Cisco uBR7200 series. |
To verify that cable flap list aging is set, enter the show cable flap list command:
CMTS01# show cable flap list
Mac Addr CableIF Ins Hit Miss CRC P-Adj Flap Time
0010.7b6b.5d1d C3/0 U0 0 688 169 0 0 3 Nov 5 12:28:50
0010.7b6b.5e15 C3/0 U0 1 707 185 0 0 5 Nov 5 12:29:52
0010.7b6b.5e27 C3/0 U0 1 707 198 0 0 5 Nov 5 12:29:55
0010.7b6b.5d29 C3/0 U0 1 709 205 0 0 5 Nov 5 12:29:52
0010.7b6b.5e2b C3/0 U0 1 710 204 0 0 7 Nov 5 12:30:16
You can set the cable flap list insertion time. When a cable modem makes an insertion request more frequently than the amount of insertion time defined by this command, the cable modem is placed in the flap list for activity recording. The valid range is from 60 to 86400 seconds.
To set the cable flap list insertion time, use the following command in global configuration mode.
| Command | Purpose |
|---|---|
CMTS01(config)# cable flap-list insertion-time seconds | Specify the insertion time in seconds. Any cable modem that makes an insertion request more frequently than this period of time is placed in the flap list. |
To verify cable flap list insertion time, enter the show cable flap list command:
CMTS01# show cable flap list
Mac Addr CableIF Ins Hit Miss CRC P-Adj Flap Time
0010.7b6b.5d1d C3/0 U0 0 688 169 0 0 3 Nov 5 12:28:50
0010.7b6b.5e15 C3/0 U0 1 707 185 0 0 5 Nov 5 12:29:52
0010.7b6b.5e27 C3/0 U0 1 707 198 0 0 5 Nov 5 12:29:55
0010.7b6b.5d29 C3/0 U0 1 709 205 0 0 5 Nov 5 12:29:52
0010.7b6b.5e2b C3/0 U0 1 710 204 0 0 7 Nov 5 12:30:16
You can specify the power adjustment threshold that will cause a flap-list event to be recorded. When the power adjustment of a cable modem meets or exceeds the threshold, the cable modem is placed in the flap list. The valid range is from 1 to 10 dBmV.
|
Note A power adjustment threshold of less than 2 dBmV might cause excessive flap list event recording. Cisco recommends setting this threshold value to 3 dBmV or higher. |
| Command | Purpose |
|---|---|
CMTS01(config)# cable flap-list power-adjust threshold dbmv | Specify the minimum power adjustment that will constitute a flap-list event. |
To verify the cable flap list power adjustment threshold, enter the show cable flap list command:
CMTS01# show cable flap list
Mac Addr CableIF Ins Hit Miss CRC P-Adj Flap Time
0010.7b6b.5d1d C3/0 U0 0 688 169 0 0 3 Nov 5 12:28:50
0010.7b6b.5e15 C3/0 U0 1 707 185 0 0 5 Nov 5 12:29:52
0010.7b6b.5e27 C3/0 U0 1 707 198 0 0 5 Nov 5 12:29:55
0010.7b6b.5d29 C3/0 U0 1 709 205 0 0 5 Nov 5 12:29:52
0010.7b6b.5e2b C3/0 U0 1 710 204 0 0 7 Nov 5 12:30:16
You can specify the miss threshold for recording a flap-list event. A miss is the number of times a cable modem does not acknowledge a MAC layer keepalive message from a cable modem card. An 8% miss rate is normal for the Cisco cable modem cards. When the number of misses exceeds the threshold, the cable modem is placed in the flap list.
|
Note A high miss rate can indicate intermittent upstream problems, fiber laser clipping, or common-path distortion. |
| Command | Purpose |
|---|---|
CMTS01(config)# cable flap-list miss-threshold misses | Specify the number of MAC-layer keepalive misses that will result in the cable modems being place in the flap list. |
To verify the cable flap list miss threshold, enter the show cable flap list command:
CMTS01# show cable flap list
Mac Addr CableIF Ins Hit Miss CRC P-Adj Flap Time
0010.7b6b.5d1d C3/0 U0 0 688 169 0 0 3 Nov 5 12:28:50
0010.7b6b.5e15 C3/0 U0 1 707 185 0 0 5 Nov 5 12:29:52
0010.7b6b.5e27 C3/0 U0 1 707 198 0 0 5 Nov 5 12:29:55
0010.7b6b.5d29 C3/0 U0 1 709 205 0 0 5 Nov 5 12:29:52
0010.7b6b.5e2b C3/0 U0 1 710 204 0 0 7 Nov 5 12:30:16
You can specify the maximum number of cable modems that can be listed in the cable flap list tables. The valid range is from 1 to 8192 cable modems. The default is 8192 cable modems.
| Command | Purpose |
|---|---|
CMTS01(config)# cable flap-list size number | Specify the maximum size of the flap list. |
To verify the cable flap list size, enter the show cable flap list command:
CMTS01# show cable flap list
Mac Addr CableIF Ins Hit Miss CRC P-Adj Flap Time
0010.7b6b.5d1d C3/0 U0 0 688 169 0 0 3 Nov 5 12:28:50
0010.7b6b.5e15 C3/0 U0 1 707 185 0 0 5 Nov 5 12:29:52
0010.7b6b.5e27 C3/0 U0 1 707 198 0 0 5 Nov 5 12:29:55
0010.7b6b.5d29 C3/0 U0 1 709 205 0 0 5 Nov 5 12:29:52
0010.7b6b.5e2b C3/0 U0 1 710 204 0 0 7 Nov 5 12:30:16
| Command | Purpose |
|---|---|
CMTS01(config)# clear cable flap-list mac-addr | Clear the entries in the cable flap list for the cable modem with this MAC address. |
The following displays flap list with different sorting options:
show cable modem flap-list [cable <n> | sort-flap | sort-time | sort-interface]
The following sets the threshold value for link establishment:
[no] cable flap-list insertion-time <sec>
|
Note A modem is tagged as flapping if the insertion time exceeds this value. Its value can be set from 60 to 86400 seconds with a default of 180 seconds. |
The following sets the number of consecutive missed station maintenance(RNG-RSP) messages that must be missed for a `flap' event to occur. Value ranges from 1-12 with a default of 6 seconds. The hits and miss counters are not affected:
[no] cable flap-list miss-threshold <miss-threshold>
The following clears the counters for a cable modem (or all cable modems) in the station maintenance list:
clear cable modem { <mac-addr> | <ip-addr> | all } counters
The following displays the QoS, modem status, In and Out octets, IP and MAC addresses per SID:
show int cable slot/port sid
The following drops the modem's RF link by removing a modem from the keep-alive polling list. This forces the modem to reset:
clear cable-modem { <mac-addr> | <ip-addr> | all } reset
The following uses a MAC layer ping to determine if the cable modem is online. It uses smaller data units on the wire than a standard IP ping, resulting in lower overhead. Works even if the IP layer in the modem is down or hasn't completed registration:
ping DOCSIS cable-modem <mac-addr | IP address >
The following displays the timing offset, receive power, and QoS values by cable interface, SID, and MAC address:
show cable modem [<ip-address> | <MAC-address>]
The following displays the current allocation table and frequency assignments:
show cable spectrum-group [spectrum group number]
The following displays maximum, average, and minimum% online time and offline times for a given SID on a given Cisco uBR7200 interface:
show int slot/port sid connectivity
The following displays input and output rates, input errors, CRC, frames, overruns, underruns, collisions, interface resets. High input errors in the CMTS retrieved from this query suggests noisy upstream. In older versions of the chassis, loose midplane and line card screws caused a similar problem:
show interface slot/downstream-port
The Cisco uBR7200 series uses an averaging algorithm to determine the optimum power level for a cable modem with low carrier-to-noise ratio that is making excessive power adjustments---known as flapping. To avoid dropping flapping cable modems, the Cisco uBR7200 series universal broadband router averages a configurable number of RNG-REQ messages before it makes power adjustments. By compensating for a potentially unstable return path, the Cisco uBR7200 series router maintains connectivity with affected cable modems. You can interpret these power adjustments, however, as indicating unstable return path connections.
The show cable flap-list and show cable modem commands are expanded to indicate which paths the Cisco uBR7200 series is making power adjustments and which modems have reached maximum transmit power settings. These conditions indicate unstable paths that should be serviced.
The following example shows the output of the show cable flap-list command:
router# show cable flap-list MAC Address Upstream Ins Hit Miss CRC P-Adj Flap Time 0010.7bb3.fd19 Cable5/0/U1 0 2792 281 0 *45 58 Jul 27 16:54:50 0010.7bb3.fcfc Cable5/0/U1 0 19 4 0 !43 43 Jul 27 16:55:01 0010.7bb3.fcdd Cable5/0/U1 0 19 4 0 *3 3 Jul 27 16:55:01
The * symbol indicates that the CMTS is using the power adjustment method on this modem. The ! symbol indicates that the modem has reached maximum transmit power.
Output of the show cable modem command appears below:
router# show cable modem
Interface Prim Online Timing Rec QoS CPE IP address MAC address
Sid State Offset Power
Cable3/0/U0 1 online 2257 0.00 3 0 10.30.128.142 0090.8330.0217
Cable3/0/U0 2 online 2262 *-0.50 3 0 10.30.128.145 0090.8330.020f
Cable3/0/U0 3 online 2260 0.25 3 0 10.30.128.146 0090.8330.0211
Cable3/0/U0 4 online 2256 *0.75 3 0 10.30.128.143 0090.8330.0216
Cable3/0/U0 5 online 2265 *0.50 3 0 10.30.128.140 0090.8330.0214
Cable3/0/U0 6 online 2256 0.00 3 0 10.30.128.141 0090.8330.0215
Cable3/0/U0 7 online 4138 !-1.00 3 1 10.30.128.182 0050.7366.124d
Cable3/0/U0 8 online 4142 !-3.25 3 1 10.30.128.164 0050.7366.1245
Cable3/0/U0 9 online 4141 !-3.00 3 1 10.30.128.185 0050.7366.17e3
Cable3/0/U0 10 online 4142 !-2.75 3 0 10.30.128.181 0050.7366.17ab
Cable3/0/U0 11 online 4142 !-3.25 3 1 10.30.128.169 0050.7366.17ef
Similar to the show cable flap-list display, the * symbol in the show cable modem output indicates that the CMTS is using the power adjustment method on this CM. The ! symbol indicates that the CM has reached maximum transmit power.
This section documents the commands pertaining to amplitude averaging:
To enable or disable the power adjustment capability, use the following commands:
cable upstream n power-adjust {threshold [threshold #] | continue [tolerable value] | noise [% of power adjustment]}
| Syntax | Valid Values |
n | Specifies the upstream port number. |
threshold # | Specifies the power adjustment threshold. The threshold range is from 0 through 10 dB. The default is 1 dB. |
tolerable value | Determines if the status of the RNG-RSP should be set to CONTINUE or SUCCESS. The range is from 2 through 15 dB. The default is 2 dB. |
% of power adjustment | Specifies the percentage of power adjustment packets required to switch from the regular power adjustment method to the noise power adjustment method. Range is from 10 through 100 percent. The default is 30 percent. |
|
Note The threshold default is 1 dB. The tolerable value default is 2 dB. The power adjustment is 30 percent. |
|
Caution Default settings are adequate for system operation. Amplitude averaging is an automatic procedure. In general, Cisco does not recommend you adjust values. Cisco does recommend, however, that you clean up your cable plant should you encounter flapping cable modems. |
|
Note In some instances, you might adjust certain values: If CMs cannot complete ranging because they have reached maximum power levels, you might try to set the tolerable value CONTINUE field to a larger value than the default of 2 dB. Values larger than 10 dB on "C" versions of cable modem cards, or 5 dB on FPGA versions, are not recommended. If the flap list shows CMs with a large number of power adjustments, but the CMs are not detected as "noisy," you might try to decrease the percentage for "noisy." If you think too many CMs are unnecessarily detected as "noisy," you might try to increase it. |
To control power adjustment methods by setting the frequency threshold, use the cable upstream freq-adj averaging interface configuration command. To disable power adjustments, use the no form of this command.
cable upstream n freq-adj averaging % of frequency adjustment
| Syntax | Valid Values |
n | Specifies the upstream port number. |
averaging | Specifies that a percentage of frequency adjustment packets is required to change the adjustment method from the regular power adjustment method to the noise power adjustment method. |
% of frequency adjustment | Specifies the percentage of frequency adjustment packets required to switch from the regular power adjustment method to the noise power adjustment method. Valid range is from 10 through 100 percent. |
The following example shows how to change the power adjustment method when the frequencyadjustment packet count reaches 50 percent:
router(config-if)# cable upstream 0 freq-adj averaging 50
This feature provides configuration commands that allow you to create downstream test signals. Both Pseudo Random Bit Stream (PRBS) and unmodulated carrier test signals are now supported.
A PRBS test signal is a random data pattern that has been modulated to look like a real data stream. An unmodulated test signal is a continuous sine wave that looks like a carrier wave on the downstream transmission.
See the following required tasks to create PRBS and unmodulated carrier test signals:
| Step | Command | Purpose | ||
|---|---|---|---|---|
1. | # router(config-if)# cable downstream if-output continuous-wave | Generates an unmodulated continuous-wave signal on the downstream channel. The interface is shut down. | ||
2. | Router(config-if)# no cable downstream if-output | Stops sending test signals.
|
| Step | Command | Purpose | ||
|---|---|---|---|---|
1. | # router(config-if)# cable downstream if-output prbs | Generates a PRBS test signal on the downstream channel. The interface is shut down. | ||
2. | Router(config-if)# no cable downstream if-output | Stops sending test signals.
|
To verify the output of a continuous-wave test signal or the output of a PRBS test signal, use a spectrum analyzer on the downstream channel. The downstream carrier is enabled as a default.
The standard mode of operation is modulated signal output and the interface is active. For PRBS and continuous wave output, the selected interface will be shut down.
The functioning of the no cable downstream if-output command has not changed. The interface is shut down.
Information the Ping DOCSIS feature includes a real-time view and plot of requested power adjustments, as well as a measure of optimal headend reception power. This gives the cable operator the ability to solicit a configurable number of periodic ranging requests from a cable modem.
To ping a specific cable modem to determine if it is online, use the following command in EXEC mode.
| Command | Purpose |
|---|---|
CMTS01# ping docsis addr | Ping the cable modem with a specific MAC address or IP address to see if it is online. |
The ping docsis command returns a verification from a cable modem that is pinged:
Queueing 5 MAC-layer station maintenance intervals, timeout is 25 msec: !!!!! Success rate is 100 percent (5/5)
|
Tips If you are having trouble, make sure you are using a valid MAC or IP address for the cable modem you want to ping. |
To troubleshoot cable interfaces, use the following debug commands in enable (privileged EXEC) mode.
| Command | Purpose | ||
|---|---|---|---|
| View all debug cable commands that are available. | ||
| Turn off all debugging information to the console and choose a more selective debug command.
|
|
Caution The following commands can generate large amounts of output as the number of cable modems grows. On heavily loaded systems with thousands of cable modems, these commands can dramatically affect router performance. |
This command activates debugging of arp requests on the cable interfaces. When this command is activated, all cable arp request messages are displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable arp
To deactivate debugging of arp requests, use the following command:
CMTS01# no debug cable arp
This command activates debugging of the Cisco uBR7200 series environmental monitor. When this command is activated, all environmental monitor messages are displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable envm
To deactivate debugging of the environmental monitor, use the following command:
CMTS01# no debug cable envm
This command activates debugging of cable MAC protocol errors. When this command is activated, any errors that occur in the cable MAC protocol are displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable err
To deactivate debugging of MAC protocol errors, use the following command:
CMTS01# no debug cable err
This command activates debugging of baseline privacy. The format for the command follows:
CMTS01# debug cable privacy
To deactivate debugging of baseline privacy, use the following command:
CMTS01# no debug cable privacy
This command activates debugging of the tek and kek baseline privacy key activity. When this command is activated, all activity related to kek and tek keys is displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable keyman
To deactivate debugging of the keys, use the following command:
CMTS01# no debug cable keyman
This command activates debugging of messages generated in the cable MAC that frames and encrypts downstream RF signals. When this command is activated, messages generated by the cable MAC are displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable mac-messages
To deactivate debugging of cable MAC messages, use the following command:
CMTS01# no debug cable mac-messages
This command activates debugging of cable maps that identify data on cable interfaces. When this command is activated, messages related to cable maps are displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable map
To deactivate debugging of cable maps, use the following command:
CMTS01# no debug cable map
This command activates debugging of cable modems. When this command is activated, messages from cable modems on the HFC network are displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable modems
To deactivate debugging of cable MAC messages, use the following command:
CMTS01# no debug cable modems
This command activates debugging of messages generated in the cable PHY---the physical layer where upstream and downstream activity between the Cisco uBR7200 series and the HFC network is controlled. When this command is activated, messages generated in the cable PHY are displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable phy
To deactivate debugging of the cable PHY, use the following command:
CMTS01# no debug cable phy
This command activates debugging of QoS. When this command is activated, messages related to QoS parameters are displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable qos
To deactivate debugging of QoS, use the following command:
CMTS01# no debug cable qos
This command activates debugging of ranging messages from cable modems on the HFC network. When this command is activated, ranging messages generated when cable modems request or change their upstream frequencies are displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable range
To deactivate debugging of cable modem ranging, use the following command:
CMTS01# no debug cable range
This command activates debugging of upstream messages from cable modems. When this command is activated, any messages generated by cable modems and sent to the Cisco uBR7200 series will be displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable receive
To deactivate debugging of upstream messages, use the following command:
CMTS01# no debug cable receive
This command activates debugging of registration requests from cable modems on the HFC network. When this command is activated, messages generated by cable modems as they make requests to connect to the network are displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable reg
To deactivate debugging of cable registration, use the following command:
CMTS01# no debug cable reg
This command activates debugging of reset messages from cable modems on the HFC network. When this command is activated, reset messages generated by cable modems are displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable reset
To deactivate debugging of cable reset messages, use the following command:
CMTS01# no debug cable reset
This command activates debugging of spectrum management (frequency agility) on the HFC network. When this command is activated, messages generated because of spectrum group activity are displayed on the Cisco uBR7200 series console. Spectrum group activity can be additions or changes to spectrum groups, or frequency and power level changes controlled by spectrum groups. The format for the command follows:
CMTS01# debug cable specmgmt
To deactivate debugging of cable spectrum management, use the no debug cable specmgmt command:
CMTS01# no debug cable specmgmt
This command activates debugging of channel allocations on the HFC network. When this command is activated, messages generated when channels are allocated to cable modems on the HFC network are displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable startalloc
To deactivate debugging of cable channel allocations, use the no debug cable startalloc command:
CMTS01# no debug cable startalloc
This command activates debugging of transmissions from the Cisco uBR7200 series across the HFC network. When this command is activated, messages generated at the headend are displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable transmit
To deactivate debugging of cable transmissions, use the no debug cable transmit command:
CMTS01# no debug cable transmit
This command activates debugging of upstream channel change (UCC) messages generated when cable modems request or are assigned a new channel. When this command is activated, messages related to upstream channel changes are displayed on the Cisco uBR7200 series console. The format for the command follows:
CMTS01# debug cable ucc
To deactivate debugging of cable upstream channel changes, use the following command:
CMTS01# no debug cable ucc
This command activates debugging of upstream channel descriptor (UCD) messages. UCD messages contain information about upstream channel characteristics and are sent to the cable modems on the HFC network. Cable modems that are configured to use enhanced upstream channels use these UCD messages to identify and select an enhanced upstream channel to use. When this command is activated, messages related to upstream channel descriptors are displayed on the Cisco uBR7200 series console. The format for the command is as follows:
CMTS01# debug cable ucd
To deactivate debugging of cable upstream channel descriptor, use the following command:
CMTS01# no debug cable ucd
Cisco IOS Release 12.1(1a)T1 introduced clock card commands that included:
Cisco IOS Release 12.1(1a)T1 modified commands to support clock card operation include:
To reset the counters that are displayed with the show controllers clock-reference command, use the cable clock clear-counters privileged EXEC command.
cable clock clear-counters
This command resets any counters that were displayed from the last time the show controllers clock-reference command was used.
To select the external timing source when the clock card is in holdover mode, use the cable clock force global configuration command. To disable the selection and return to the default, use the no form of this command.
cable clock force {primary | secondary}
no cable clock force
Setting the cable clock to primary forces the primary source to act as the clock reference. Setting the cable clock to secondary forces the secondary source to act as the clock reference.
The clock card automatically uses the primary external source, if available. If the primary source fails, the clock card enters holdover mode and after a few seconds, switches to the secondary external source. The clock card switches back to the primary source when it becomes available.
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Note This command overrides the default behavior of the clock card, when the clock card is in holdover mode. If the clock card is not in holdover mode, this command is ignored. You cannot force the reference to a port if the clock card is in free-running mode. The clock card enters holdover mode if the forced reference is lost, even if the other external reference is available. |
To make the midplane TDM clock the primary timing reference for the clock card, use the cable clock source-midplane global configuration command. To disable the selection and return to the default, use the no form of this command.
cable clock source-midplane
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Note Because the clock card automatically provides the timing reference to the midplane TDM clock, the midplane cannot in turn act as the reference for the clock card. This means that the cable clock source-midplane command does not take effect unless a port adapter is configured as the primary clock reference source for the midplane. |
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Caution Although the cable clock source-midplane command is configurable, it is ignored, until a port adapter that can serve as the midplane clock reference source is supported in the Cisco uBR7246 VXR. Currently, there are no port adapters on the Cisco uBR7246 VXR that support this. |
To display clock reference status information for the clock card, use the show cable clock privileged EXEC command:
show cable clock
The following sample output from the show cable clock command shows both external sources are available and the clock card is providing the clock reference:
Router# show cable clock Clockcard primary input is present Clockcard secondary input is present Cable clock reference is clockcard primary input Cable3/0 Timestamp clock reference is from Clockcard Cable4/0 Timestamp clock reference is from Clockcard
To display hardware information, register values, and current counters for the cable clock card, use the show controllers clock-reference privileged EXEC command.
show controllers clock-reference
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Tips To reset the counters that are displayed with the show controllers clock-reference command, use the Clear Clock Counters command. |
The following is sample output from the show controllers clock-reference command:
Router# show controllers clock-reference National clock card with T1 controller Control register :0x4 Status register :0x54 LIU Config Register 0:0x0 LIU Config Register 1:0x0 1 events reported in 266636 seconds Primary active :1, LOS :0 Secondary active :0, LOS :1 Holdovers :0, HW faults :0
To display diagnostic information for the cable modem cards, use the show diag command in privileged EXEC mode.
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Tips Use the show diag command to display diagnostic information about the port adapters installed in the router. This command also displays information about the cable clock card, if installed. |
The following is sample output from the show diag command displaying diagnostic information for the cable clock card:
router# show diag Clockcard: National clock card with T1 controller EEPROM contents at hardware discovery: Hardware Revision :1.1 Part Number :800-05867-02 Board Revision :11 Deviation Number :0-0 Fab Version :02 PCB Serial Number :CAB04046NXV RMA Test History :00 RMA Number :0-0-0-0 RMA History :00 EEPROM format version 4 EEPROM contents (hex): 0x00:04 FF 40 01 AC 41 01 01 C0 46 03 20 00 16 EB 02 0x10:42 31 31 80 00 00 00 00 02 02 C1 8B 43 41 42 30 0x20:34 30 34 36 4E 58 56 03 00 81 00 00 00 00 04 00
Table 4-33 describes the fields shown in the show diag display.
| Field | Description |
|---|---|
National clock card with T1 controller | The system has identified the cable clock card. |
EEPROM contents at hardware discovery | EEPROM programmed data present when the system identified the clock card. |
Hardware Revision | Version number of the card. |
Part Number | The part number of the card. |
Board Revision | Revision number (signifying a minor revision) of the card. |
Deviation Number | Revision number (signifying a minor deviation) of the card. |
Fab Version | Manufacturing fabrication version number. |
PCB Serial Number | Serial number of the printed circuit board. |
RMA Test History | Counter indicating how many times diagnostics have been performed on this card. |
RMA Number | Return material authorization number, which is an administrative number assigned if the card needs to be returned for repair. |
RMA History | Counter indicating how many times the card has been returned and repaired. |
EEPROM format version | Version number of the EEPROM format. |
EEPROM contents (hex) | Dumps of EEPROM programmed data. |
To display information about the midplane TDM clock reference, use the show frame-clocks privileged EXEC command.
show frame-clocks
The following sample output from the show frame-clocks command shows that there are no clock sources configured and the clock card is the default clock source:
Router# show frame-clocks Priority 1 clock source:not configured input:none Priority 2 clock source:not configured input:none Priority 3 clock source:not configured input:none Priority 4 clock source:not configured input:none Current clock source:Clockcard, input:Primary, priority:5
Table 4-34 describes the fields shown in the show frame-clocks display:
| Field | Description |
|---|---|
Priority 1-4 clock source | The configuration of the four network clock sources. |
Current clock source | The current clock source, its input, and priority. In this example, the clock card is providing the clock source. |
To display general information about the router when reporting a problem, use the show tech-support privileged EXEC command.
show tech-support [page] [<password>]
The page option causes the output to display a page of information at a time. Use the Return key to display the next line of output or use the space bar to display the next page of information. If not used, the output scrolls (that is, does not stop for page breaks).
The password option leaves passwords and other security information in the output. If not used, passwords and other security-sensitive information in the output are replaced with the label "<removed>" (this is the default).
Use this command to help collect general information about the router when you are reporting a problem. This command displays the equivalent of the following show commands:
Posted: Fri Jun 2 16:18:23 PDT 2000
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