Downstream Resiliency Bonding Group

With more wideband (WB) modems being deployed in cable plants, WB modem resiliency is an important feature. When a comparatively smaller number of cable modems (CMs) observe an impairment on an RF channel, that RF channel stops working. It impacts all the CM using that RF channel, irrespective of whether they reported the impairment on that RF channel. Instead, the solution should be to communicate with the affected cable modems using the good RF channel, without affecting the other cable modems.

The Downstream Resiliency Bonding Group feature allows cable modems with multiple impaired RF channels to be allocated to a dynamically-created wideband interface, which ensures that the performance of the wideband cable modems is not drastically affected.

Your software release may not support all the features that are documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. The Feature Information Table at the end of this document provides information about the documented features and lists the releases in which each feature is supported.

Contents

Hardware Compatibility Matrix for the Cisco cBR Series Routers


Note
The hardware components that are introduced in a given Cisco IOS-XE Release are supported in all subsequent releases unless otherwise specified.
Table 1. Hardware Compatibility Matrix for the Cisco cBR Series Routers

Cisco CMTS Platform

Processor Engine

Interface Cards

Cisco cBR-8 Converged Broadband Router

Cisco IOS-XE Release 16.5.1 and Later Releases

Cisco cBR-8 Supervisor:

  • PID—CBR-SUP-250G

  • PID—CBR-CCAP-SUP-160G

Cisco IOS-XE Release 16.5.1 and Later Releases

Cisco cBR-8 CCAP Line Cards:

  • PID—CBR-LC-8D30-16U30

  • PID—CBR-LC-8D31-16U30

  • PID—CBR-RF-PIC

  • PID—CBR-RF-PROT-PIC

  • PID—CBR-CCAP-LC-40G

  • PID—CBR-CCAP-LC-40G-R

  • PID—CBR-CCAP-LC-G2-R

  • PID—CBR-SUP-8X10G-PIC

  • PID—CBR-2X100G-PIC

Digital PICs:

  • PID—CBR-DPIC-8X10G

  • PID—CBR-DPIC-2X100G

Cisco cBR-8 Downstream PHY Module:

  • PID—CBR-D31-DS-MOD

Cisco cBR-8 Upstream PHY Modules:

  • PID—CBR-D31-US-MOD

Note

Do not use DPICs (8X10G and 2x100G) to forward IP traffic, as it may cause buffer exhaustion, leading to line card reload.

The only allowed traffic on a DPIC interface is DEPI, UEPI, and GCP traffic from the Cisco cBR-8 router to Remote PHY devices. Other traffic such as DHCP, SSH, and UTSC should flow via another router, since DPICs cannot be used for normal routing.

Prerequisites for Downstream Resiliency Bonding Group

  • Set aside WB interfaces so that new WB interfaces can be dynamically created from the reserved list of WB interfaces.

  • Free up RF bandwidth so that those RF channels can be added to a resiliency bonding group (RBG).

  • Remove all existing RBG configuration from the WB interface.

Restrictions for the Downstream Resiliency Bonding Group

  • If an existing wideband interface is reserved as a Resiliency Bonding Group (RBG) and later the RBG is removed (through the no cable ds-resiliency command), the modems using this RBG go offline and the RBG configuration itself is deleted. Therefore, it is highly recommended that users should not configure an existing BG as an RBG.

  • This feature is enabled only when the number of cable modems observing an RF channel impairment is below the resiliency threshold. If the number of cable modems on an impaired RF channel is above the resiliency threshold, the impaired RF channel is temporarily removed from the bonding group.

  • A cable modem is assigned to an RBG on a first-come-first-served basis. To handle this feature optimally, it is recommended to set aside more WB interfaces and RF channel bandwidth.

  • The Cisco CMTS controls the freeing of unused RBGs, when there is no modem using the RGB. The freeing of the unused RGB may take some time and the RGB, which is not completely free cannot be used by the modems. Irrespective of the number of configured RBGs, if all the old RBGs are not completely set free and if the Cisco CMTS tries to move the cable modem to a new RBG, the Cisco CMTS moves the cable modem to the primary DS channel instead of RBG.

  • Only SFs on the WB interface associated with the primary SF are moved to an RBG. SFs on other interfaces will not be moved.

  • Static SFs are assigned to an RBG on a best effort quality of service (QoS).

  • If the resiliency rf-change-trigger setting does not have the secondary keyword set, only the primary SF is moved to the RBG or a NB interface.

  • If the Downstream Resiliency Bonding Group feature is not enabled to use an RBG, only cable modems with impairments on the primary WB interface are moved to the NB interface.

  • SFs carrying multicast traffic are not moved.

There may not be enough reserved bonding groups to support all modems facing an impairment at any given time thus the following restrictions must be considered:

  • Each RBG has at least two RF channels.

  • RBG RF assignments are always a subset of the RF channel assignment of the parent WB interface.

  • If an RBG is unavailable for a cable modem, the SF of the CM is moved to a NB interface.

  • If a high percentage of cable modems experience an RF impairment and there are no more available bonding group IDs, the impaired RF itself may be removed from the bonding group. Removal of an impaired RF from a parent bonding group is also reflected in the RBG. If an RBG drops to a single RF, all SFs are moved to the NB interface.

The Downstream Resiliency Bonding Group feature has the following cross-functional restrictions:

  • All Dynamic service flows, whether they require a committed information rate (CIR) or not, typically voice flows, are created on the NB interface when an RF channel is impaired. Because all SFs assigned to an RBG are best effort only, voice calls may report a quality issue.

  • Cable modems participating in the resiliency mode do not take part in load balancing.

  • The Downstream Resiliency Bonding Group feature is only supported in the Dynamic Bandwidth Sharing (DBS) mode.

Information About Downstream Resiliency Bonding Group

You can set aside unused bonding groups as RBGs. Ensure that each RF channel is assigned at least 1% of the available bandwidth. Use the cable rf-channel bandwidth-percent command to configure the RF channel bandwidth.


Note

If the bandwidth-percent is set to 100, the Cisco CMTS does not add any RFs to the RBG. In other words, this feature will not be enabled.

The Cisco CMTS controls the assignment and freeing of unused RBGs. If an RF channel is removed from a WB interface, it is also removed from any associated RBGs.


Note

If the wideband interface is in standby mode, the Cisco CMTS does not assign or free up the unused downstream bonding group.

A suspended RF channel is restored for all affected wideband interfaces when a specified number of cable modems report (via CM-STATUS) that the channel connectivity is restored. The Wideband Modem Resiliency feature defines the specified number of cable modems as half of the configured count or percentage of rf-change-trigger, or both. For example, if the count is 20 and the percent is 10, then the number of cable modems reporting recovery should reduce the count to 10 and the percent to 5 for the suspended RF channel to be restored.

Table 2. Feature History

Feature Name

Release Information

Feature Description

Configuring maximum RBG moves and viewing CM RBG usage statistics.

Cisco IOS XE Dublin 17.12.1w

If a CM is currently at the configured limit, and it reports a new DS impairment, the CM moves to narrow band (primary DS only). CM-STATUS recovery events are still handled for CMs that are currently at the configured limit.

You can use the cable resiliency cm-max-rbg-moves command to configure the maximum number of times a CM can be moved to any RBG within the configured interval.

Use the show cable modem rbg-activity to view CM RBG usage statistics.

Finding a Best-Fit RBG for the Cable Modem

A bonding group is a list of channels that provide a means to identify the channels that are bonded together. The Cisco CMTS assigns a service flow (SF) to an RBG based on the attributes of the SF and the attributes of the individual channels of the bonding group.

In the Downstream Resiliency Bonding Group feature, when a line card receives a CM-STATUS message from the cable modem informing the line card that there is an RF channel impairment, the line card checks for the number of good RF channels and:

  • Moves the cable modem to narrowband mode if there is only one available RF channel.

  • Moves the cable modem to wideband mode if the cable modem reports all RF channels are in good state.

  • Moves the cable modem to an RBG if there are two or more good RF channels, with at least one RF channel impaired, and if the Downstream Resiliency Bonding Group feature is enabled.

When the Cisco CMTS receives a message from the line card to move a cable modem to an RBG, the Cisco CMTS attempts to find an existing RBG or creates an RBG that satisfies the impairment.


Note

If two or more RBGs are reserved for the same wideband controller, the Cisco CMTS creates one RBG for each cable modem.


Note

The Cisco CMTS creates more than one RBG from a parent WB interface if the user has set aside more than one WB interface as the RBG and the RF bandwidth does not exceed 100%.

If a matching RBG is not found or cannot be created, the Cisco CMTS looks for an RBG with a subset of the required RF channels and if available, the cable modem is assigned to such an RBG.

However, if no such RBG exists, the Cisco CMTS instructs the line card to move the cable modem to NB mode.

Table 3. Feature History

Feature Name

Release Information

Feature Description

Resiliency Bonding Group (RBG) Commands

Cisco IOS XE Dublin 17.12.1w

In this release you can:

How to Configure Downstream Resiliency Bonding Group

This section contains the following:

Enabling Downstream Resiliency Bonding Group

Procedure

  Command or Action Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

cable rf-change-trigger {percent value | count number } [secondary ]

Example:

Router(config)# cable rf-change-trigger percent 50 count 1 secondary

Specifies the amount of time an event must persist before it triggers an action for the reporting CM.

Step 4

cable resiliency ds-bonding

Example:

Router(config)# cable resiliency ds-bonding

Enables the downstream resiliency bonding group.

Step 5

exit

Example:

Router(config)# exit

Returns to the global configuration mode.

What to do next


Note

The result of using the cable rf-change-trigger command with the cable resiliency ds-bonding command is different from using only the cable rf-change-trigger command. For more information, see Downstream Resiliency Narrowband Mode Versus Resiliency Bonding Group.

Reserving a Resiliency Bonding Group for a Line Card

This section describes reserving a bonding group or a wideband interface for a line card per controller.


Restriction

When you reserve a resiliency bonding group using the cable ds-resiliency command, the existing bundle and RF channel configurations on the wideband interface will be removed automatically. Other configurations like admission control, should be removed manually.

After downstream resiliency bonding group is configured, avoid other manual configurations.

Procedure

  Command or Action Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

interface wideband-cable slot/subslot/port :wideband-channel

Example:

Router(config)# interface wideband-cable 1/0/0:7

Configures a wideband cable interface.

Step 4

cable ds-resiliency

Example:

Router(config-if)# cable ds-resiliency

Reserves an individual bonding group or WB interface for usage on a line card, on a per controller basis.

Step 5

exit

Example:

Router(config-if)# exit

Returns to the global configuration mode.

Moving a DS Partial Cable Modem Back to the Original BG

Table 4. Feature History

Feature Name

Release Information

Feature Description

Moving a DS Partial Cable Modem Back to the Original BG

Cisco IOS XE Dublin 17.12.1x

In this release, you can move a DS Partial cable modem back to the original BG. The cable modem remains online and does not reset or reinitialize partial service modems. The cable modem recovers to the w-online state.

You can use this feature to recover cable modems that may send the cm-status recovery events which are not received by the cable modem.

Cisco can provide the feature details upon request.

Verifying Downstream Resiliency Bonding Group Configuration

This section contains the following:

Verifying the Downstream Resiliency Bonding Group

To verify if the Downstream Resiliency Bonding Group feature is enabled, use the show cable modem resiliency command as shown in the following example: 


Router# show cable modem resiliency
                              Orig BG                Curr BG
I/F     MAC Address    ID   I/F           RFs ID   I/F           RFs
------- -------------- ---------------------- ----------------------
C7/0/0  0025.2eaf.843e 897  Wi7/0/0:0     4   898  Wi7/0/0:1     3  
C7/0/0  0025.2eaf.8356 897  Wi7/0/0:0     4   899  Wi7/0/0:2     3  
C7/0/0  0015.d176.5199 897  Wi7/0/0:0     4   720  In7/0/0:0

The Current BG I/F field indicates whether Downstream Resiliency Bonding Group feature is enabled and if the cable modems are assigned to a WB interface.

Starting with Cisco IOS XE Cupertino 17.9.1w, VTY injection is not used during RBG change, and the system shows the username of the last user who has performed the last configuration update.

To verify the configuration, use the show running-config command as shown in the following example: 


Router# show running-config
oad for five secs: 25%/4%; one minute: 43%; five minutes: 39%
Time source is NTP, 11:21:16.148 CST Mon Oct 17 2022

Building configuration...

Current configuration : 1305898 bytes
!
! Last configuration change at 08:43:48 CST Mon Oct 17 2022
! NVRAM config last updated at 11:19:42 CST Mon Oct 17 2022 by cstuser

Verifying a Reserved Resiliency Bonding Group

To verify if a BG is reserved for a line card, use the show cable resiliency command as shown in the following example: 


Router# show cable resiliency
              BG   Resil BG                                 RF
Resil BG I/F  ID   State          Count Time            Ctrl  Num
------------- ---- -------------- ----- --------------- ----------
Wi1/0/0:10    10   Free          
Wi1/0/0:20    20   Free          
Wi7/0/0:1     1    Assigned       3     Nov 3  09:55:49 0     0
                                                              1
                                                              2
Wi7/0/0:2     2    Assigned       3     Nov 3  09:57:09 0     0
                                                              1
                                                              3

Downstream Resiliency Narrowband Mode Versus Resiliency Bonding Group

This section provides the sample outputs when using the cable rf-change-trigger command with the cable resiliency ds-bonding command and using only the cable rf-change-trigger command.

Table 5. Downstream Resiliency Narrowband Mode Versus Resiliency Bonding Group - Scenario 1

Effect on

Using only cable rf-change-trigger command

(Downstream Resiliency NB Mode)

Using cable rf-change-trigger command with cable resiliency ds-bonding

(Downstream Resiliency Bonding Group)

Below Threshold

Above Threshold

Below Threshold

Above Threshold

Primary Service Flow

Moves to the primary channel.

Remains on the original bonding group while the impaired downstream channels are not used and are reported as DOWN.

Moves to dynamic bonding group.

Remains on the original bonding group while the impaired downstream channels are not used and are reported as DOWN.

Secondary Service Flows

Remain on the original WB interface.

Remains on the original bonding group while the impaired downstream channels are not used and are reported as DOWN.

Remains on the original bonding group.

Remains on the original bonding group while the impaired downstream channels are not used and are reported as DOWN.

The following is a sample output for a cable modem when the cable rf-change-trigger command is used with the cable resiliency ds-bonding command and the number of cable modems observing an RF channel impairment is below the resiliency threshold: 


Router# show cable modem
 
                                                                                 D
MAC Address    IP Address     I/F           MAC           Prim RxPwr  Timing Num I
                                            State         Sid  (dBmv) Offset CPE P
0023.be83.1c9e 10.1.11.46     C5/0/0/UB     w-online      922  -0.50  1055   0   N
0023.be83.1caa 10.1.11.28     C5/0/0/UB     w-online      923  0.00   1043   0   N
0025.2ecf.f19c 10.1.11.53     C5/0/0/UB     w-online      925  0.00   1057   0   N
0022.3a30.9fc0 10.1.11.47     C5/0/0/UB     w-online      926  0.00   1055   0   N
001a.c3ff.e3d4 10.1.11.39     C5/0/0/UB     p-online      927  0.00   1307   0   N
0023.be83.1c9a 10.1.11.61     C5/0/0/UB     w-online      928  0.00   1057   0   N
0022.3a30.9fbc 10.1.11.60     C5/0/0/UB     p-online      929  -0.50  1055   0   N
0023.be83.1c8c 10.1.11.38     C5/0/0/UB     w-online      930  0.00   1061   0   N
001e.6bfb.1964 10.1.11.63     C5/0/0/UB     p-online      931  0.50   1305   0   N
0025.2ecf.f196 10.1.11.29     C5/0/0/UB     w-online      932  0.00   1057   0   N
0025.2ecf.f04e 10.1.11.54     C5/0/0/UB     w-online      933  0.00   1054   0   N
0022.3a30.9fc8 10.1.11.43     C5/0/0/UB     w-online      934  0.00   1056   0   N
0025.2ecf.f190 10.1.11.55     C5/0/0/UB     w-online      935  0.00   1059   0   N
0022.3a30.9fd0 10.1.11.52     C5/0/0/UB     p-online      936  0.00   1057   0   N
0022.ce97.8268 10.1.11.31     C5/0/0/UB     w-online      937  -0.50  1056   0   N
0022.ce97.8281 10.1.11.25     C5/0/0/UB     w-online      938  0.00   1058   0   N
001a.c3ff.e4ce 10.1.11.44     C5/0/0/UB     w-online      940  -0.50  1304   0   N
0022.ce9c.839e 10.1.11.32     C5/0/0/UB     w-online      941  -0.50  1305   0   N
0022.cea3.e768 10.1.11.41     C5/0/0/UB     w-online      942  -1.00  1305   0   N
0022.ce9c.8398 10.1.11.33     C5/0/0/UB     w-online      943  0.00   1306   0   N
001a.c3ff.e50a 10.1.11.59     C5/0/0/UB     w-online      944  0.00   1304   0   N
001a.c3ff.e3f8 10.1.11.57     C5/0/0/UB     w-online      945  -1.00  1306   0   N
001e.6bfb.1a14 10.1.11.37     C5/0/0/UB     w-online      946  0.00   1305   0   N

Note

p-online indicates that cable modem has reported NP RF failure and it is in downstream partial service mode. 


Router# show cable resiliency

              BG   Resil BG                                 RF
Resil BG I/F  ID   State          Count Time            Ctrl  Num
------------- ---- -------------- ----- --------------- ----------
Wi5/0/0:2     2    Assigned       1     Mar 30 14:46:43 0     0
                                                              1
                                                              2
Wi5/0/0:3     3    Assigned       1     Mar 30 14:46:43 0     0
                                                              1
                                                              2
                                                        1     0
                                                              1
                                                              2
                                                              3
Wi5/0/0:4     4    Free           0                    
Wi5/0/0:5     5    Free           0                    

Router# show cable modem resiliency
                              Orig BG                Curr BG
I/F     MAC Address    ID   I/F           RFs ID   I/F           RFs
------- -------------- ---------------------- ----------------------
C5/0/0  001a.c3ff.e3d4 258  Wi5/0/0:1     4   259  Wi5/0/0:2     3	<- Dynamic Bonding Group
C5/0/0  0022.3a30.9fbc 257  Wi5/0/0:0     8   260  Wi5/0/0:3     7	<- Dynamic Bonding Group
C5/0/0  001e.6bfb.1964 258  Wi5/0/0:1     4   259  Wi5/0/0:2     3	<- Dynamic Bonding Group
C5/0/0  0022.3a30.9fd0 257  Wi5/0/0:0     8   260  Wi5/0/0:3     7	<- Dynamic Bonding Group

The following is a sample output for a cable modem under the following conditions:

  • cable rf-change-trigger command is used with the cable resiliency ds-bonding command

  • Number of cable modems observing an RF channel impairment is below the resiliency threshold

  • There is no available WB interface for the resiliency bonding group: 


Router# show cable modem
 0025.2ecf.f196 service-flow version

SUMMARY:
MAC Address    IP Address      Host          MAC           Prim  Num Primary    DS
                               Interface     State         Sid   CPE Downstream RfId
0025.2ecf.f196 10.1.11.29      C5/0/0/UB     p-online
      932   0   In5/0/0:0  240
Sfid  Dir Curr  Sid   Sched  Prio MaxSusRate  MaxBrst     MinRsvRate  Throughput 
          State       Type
1867  US  act   932   BE     0    0           10000       0           294        
1868  DS  act   N/A   N/A    0    0           3044        0           154 

Router# show cable resiliency
              BG   Resil BG                                 RF
Resil BG I/F  ID   State          Count Time            Ctrl  Num
------------- ---- -------------- ----- --------------- ----------
Wi5/0/0:2     2    Assigned       6     Mar 30 15:57:09 0     0
                                                              1
                                                              2
                                                              3
                                                        1     0
                                                              2
                                                              3
Wi5/0/0:3     3    Assigned       8     Mar 30 15:53:58 0     0
                                                              1
                                                              2
                                                        1     1
                                                              2
                                                              3
Wi5/0/0:4     4    Assigned       2     Mar 30 15:53:58 0     0
                                                              1
                                                              2
                                                              3
                                                        1     1
                                                              2
                                                              3
Wi5/0/0:5     5    Assigned       2     Mar 30 15:58:35 0     0
                                                              1
                                                              2
                                                              3
                                                        1     0
                                                              1
                                                              3

Router# show cable modem resiliency

                              Orig BG                Curr BG
I/F     MAC Address    ID   I/F           RFs ID   I/F           RFs
------- -------------- ---------------------- ----------------------
C5/0/0  0025.2ecf.f19c 257  Wi5/0/0:0     8   259  Wi5/0/0:2     7  
C5/0/0  0025.2ecf.f196 257  Wi5/0/0:0     8   240  In5/0/0:0    	<-- move NB for no available WB interface
C5/0/0  0025.2ecf.f04e 257  Wi5/0/0:0     8   262  Wi5/0/0:5     7  
C5/0/0  0022.3a30.9fbc 257  Wi5/0/0:0     8   260  Wi5/0/0:3     6  
C5/0/0  0022.3a30.9fd0 257  Wi5/0/0:0     8   261  Wi5/0/0:4     7
Table 6. Downstream Resiliency Narrowband Mode Versus Resiliency Bonding Group - Scenario 2

Effect on

Using only cable rf-change-trigger secondary command

(Downstream Resiliency NB Mode)

Using cable rf-change-trigger secondary command with cable resiliency ds-bonding

(Downstream Resiliency Bonding Group)

Below Threshold

Above Threshold

Below Threshold

Above Threshold

Primary Service Flow

Moves all service flows to the primary channel.

Remains on the original bonding group while the impaired downstream channels are not used and are reported as DOWN.

Moves all service flows to a dynamic bonding group.

Remains on the original bonding group while the impaired downstream channels are not used and are reported as DOWN.

Secondary Service Flows

The following is a sample output for a cable modem when the cable rf-change-trigger secondary command is used with the cable resiliency ds-bonding command and the number of cable modems observing an RF channel impairment is below the resiliency threshold: 


Router# show cable modem 0025.2ecf.f196 service-flow

SUMMARY:
MAC Address    IP Address      Host          MAC           Prim  Num Primary    DS
                               Interface     State         Sid   CPE Downstream RfId
0025.2ecf.f196 10.1.11.29      C5/0/0/UB     p-online      955   0   In5/0/0:0  240
Sfid  Dir Curr  Sid   Sched  Prio MaxSusRate  MaxBrst     MinRsvRate  Throughput 
          State       Type
1913  US  act   955   BE     0    10000000    10000       0           425        
1915  US  act   956   RTPS   7    0           3044        100000      0          
1916  US  act   957   BE     0    0           3044        50000       0          
1917  US  act   958   BE     4    0           3044        0           0          
1914  DS  act   N/A   N/A    0    100000000   20000       0           0	      <-- Primary Service-Flow
1918  DS  act   N/A   N/A    0    0           3044        0           0	      <-- Secondary Service-Flow
1919  DS  act   N/A   N/A    0    0           3044        0           0	      <-- Secondary Service-Flow
1920  DS  act   N/A   N/A    4    4500000     3044        0           0	      <-- Secondary Service-Flow
UPSTREAM SERVICE FLOW DETAIL:
SFID  SID   Requests   Polls      Grants     Delayed    Dropped    Packets   
                                             Grants     Grants
1913  955   83         0          83         0          0          92        
1915  956   0          0          0          0          0          0         
1916  957   0          0          0          0          0          0         
1917  958   0          0          0          0          0          0         
DOWNSTREAM SERVICE FLOW DETAIL:
SFID  RP_SFID QID    Flg Policer               Scheduler             FrwdIF    
                         Xmits      Drops      Xmits      Drops
1914  33210   131555     90         0          6          0          Wi5/0/0:3	<-- Dynamic Bonding Group
1918  33211   131556     0          0          0          0          Wi5/0/0:3
1919  33212   131557     0          0          0          0          Wi5/0/0:3
1920  33213   131558     0          0          0          0          Wi5/0/0:3

Troubleshooting the Downstream Resiliency Bonding Group Configuration

Use the following commands to get information on the WB interface, number of CMs in an impaired state, resiliency bonding groups, their associated bonding groups, available RF channels, and the number of CMS and service flows assigned to them:

  • debug cable wbcmts resiliency

  • debug cable wbcmts resiliency report

  • show cable resiliency

  • show cable modem resiliency

  • show cable modem wideband rcs-status

  • show cable modem service-flow verbose

  • show cable resil-rf-status

  • show cable modem summary wb-rfs

In case the CPU usage of the downstream resiliency process is high, use following commands to optimize the downstream resiliency bonding group configuration:

  • cable rf-change-up-multiplier value - The default value is 2. Use this command to set the rf-channel up dampen time as an integer multiplier of the rf-channel down dampen time, in order to lengthen the recovery time to keep certain modems from falling back into DOWN state shortly after recovery.

  • cable resiliency free-interval seconds - The recommended value is 360. Use this command to set the wait time before a created resiliency bonding group is freed/recycled, in order to hold the resiliency bonding group up long enough for it to be reused by impaired cable modems.

Configuration Examples for the Downstream Resiliency Bonding Group

The following is an example of the configuration of the Downstream Resiliency Bonding Group feature: 

cable rf-change-trigger count 10 secondary
cable resiliency ds-bonding
!
controller Upstream-Cable 9/0/1
us-channel 0 frequency 13200000
us-channel 0 channel-width 6400000 6400000
us-channel 0 power-level -1
us-channel 0 docsis-mode atdma
us-channel 0 minislot-size 8
us-channel 0 modulation-profile 221
no us-channel 0 shutdown
us-channel 1 frequency 19600000
us-channel 1 channel-width 6400000 6400000
us-channel 1 power-level -1
us-channel 1 docsis-mode atdma
us-channel 1 minislot-size 8
us-channel 1 modulation-profile 221
no us-channel 1 shutdown
us-channel 2 frequency 26000000
us-channel 2 channel-width 6400000 6400000
us-channel 2 power-level -1
us-channel 2 docsis-mode atdma
us-channel 2 minislot-size 8
us-channel 2 modulation-profile 221
no us-channel 2 shutdown
us-channel 3 frequency 32400000
us-channel 3 channel-width 6400000 6400000
us-channel 3 power-level -1
us-channel 3 docsis-mode atdma
us-channel 3 minislot-size 8
us-channel 3 modulation-profile 221
no us-channel 3 shutdown
!
controller Integrated-Cable 9/0/1
max-carrier 128
base-channel-power 34
rf-chan 0
  type DOCSIS
  frequency 381000000
  rf-output NORMAL
  power-adjust -2
  docsis-channel-id 1
  qam-profile 1
rf-chan 1 3
  type DOCSIS
  frequency 387000000
  rf-output NORMAL
  power-adjust 0
  docsis-channel-id 2
  qam-profile 1
rf-chan 32 35
  type DOCSIS
  frequency 477000000
  rf-output NORMAL
  power-adjust 0
  docsis-channel-id 33
  qam-profile 1
rf-chan 64 67
  type DOCSIS
  frequency 501000000
  rf-output NORMAL
  power-adjust 0
  docsis-channel-id 65
  qam-profile 1
rf-chan 96 99
  type DOCSIS
  frequency 669000000
  rf-output NORMAL
  power-adjust 0
  docsis-channel-id 97
  qam-profile 1
!
interface Cable9/0/1
downstream Integrated-Cable 9/0/1 rf-channel 0-3
downstream Integrated-Cable 9/0/1 rf-channel 32-35
upstream 0 Upstream-Cable 9/0/1 us-channel 0
upstream 1 Upstream-Cable 9/0/1 us-channel 1
upstream 2 Upstream-Cable 9/0/1 us-channel 2
upstream 3 Upstream-Cable 9/0/1 us-channel 3
cable upstream bonding-group 1
  upstream 0
  upstream 1
  upstream 2
  attributes 80000000
cable upstream bonding-group 2
  upstream 0
  upstream 1
  attributes 80000000
cable upstream bonding-group 3
  upstream 1
  upstream 2
  attributes 80000000
cable upstream bonding-group 4
  upstream 0
  upstream 2
  attributes 80000000
cable upstream bonding-group 5
  attributes 80000000
cable bundle 1
no cable mtc-mode
cable privacy accept-self-signed-certificate
end
!
interface Integrated-Cable9/0/1:0
cable bundle 1
cable rf-bandwidth-percent 65
!
interface Wideband-Cable9/0/1:0
cable bundle 1
cable privacy accept-self-signed-certificate
cable rf-channels channel-list 0-3 bandwidth-percent 20
!
interface Integrated-Cable9/0/1:1
cable bundle 1
cable rf-bandwidth-percent 65
!
interface Wideband-Cable9/0/1:1
cable bundle 1
cable privacy accept-self-signed-certificate
cable rf-channels channel-list 32-35 bandwidth-percent 20
!
!
interface Wideband-Cable9/0/1:60
cable ds-resiliency
!
interface Wideband-Cable9/0/1:61
cable ds-resiliency
!
interface Wideband-Cable9/0/1:62
cable ds-resiliency
!

The following is a sample output for the show cable modem command to display impaired cable modems below the resiliency threshold value: 

Router# show cable modem

MAC Address    IP Address      I/F           MAC           Prim  RxPwr  Timing Num I
                                             State         Sid   (dBmv) Offset CPE P
e448.c70c.96d5 80.17.150.6     C9/0/1/U2     p-online      1     0.00   1784   0   N
e448.c70c.96f3 80.17.150.14    C9/0/1/U1     w-online      2     -1.00  1797   0   N
68ee.9633.0699 80.17.150.31    C9/0/1/U0     w-online      3     -1.00  2088   1   N
e448.c70c.96e7 80.17.150.29    C9/0/1/U3     p-online      4     -0.50  1785   0   N
e448.c70c.982b 80.17.150.18    C9/0/1/U2     w-online      5     0.00   1780   0   N
e448.c70c.9804 80.17.150.13    C9/0/1/U3     w-online      6     -0.50  1788   0   N
e448.c70c.9819 80.17.150.30    C9/0/1/U0     w-online      7     -1.00  1782   0   N
e448.c70c.980d 80.17.150.17    C9/0/1/U0     w-online      8     -1.00  1787   0   N

Note

p-online indicates that the cable modem has reported NP RF failure and it is in downstream partial service mode.

The following is a sample output when RBGs are created: 

Router# show cable resiliency 

              BG    Resil BG                                 RF
Resil BG I/F  ID    State          Count Time            Ctrl  Num
------------- ----- -------------- ----- --------------- ----------
Wi9/0/1:60    28989 Assigned       1     Jan 9  07:35:08 1     0
                                                               1
                                                               2
Wi9/0/1:61    28990 Assigned       1     Jan 9  07:36:54 1     0
                                                               1
                                                               3
Wi9/0/1:62    28991 Free           0

The following is a sample output when cable modems service flows are assigned to RBGs: 

Router# show cable modem resiliency 

                              Orig BG                Curr BG
I/F     MAC Address    ID    I/F           RFs ID    I/F           RFs
------- -------------- ----------------------- -----------------------
C9/0/1  e448.c70c.96d5 28929 Wi9/0/1:0     4   28989 Wi9/0/1:60    3  
C9/0/1  e448.c70c.96e7 28929 Wi9/0/1:0     4   28990 Wi9/0/1:61    3

The following is a sample output of the show cable modem command when the impaired cable modems have recovered: 

Router# show cable modem

MAC Address    IP Address      I/F           MAC           Prim  RxPwr  Timing Num I
                                             State         Sid   (dBmv) Offset CPE P
e448.c70c.96d5 80.17.150.6     C9/0/1/U2     w-online      1     0.00   1784   0   N
e448.c70c.96f3 80.17.150.14    C9/0/1/U1     w-online      2     -1.00  1797   0   N
68ee.9633.0699 80.17.150.31    C9/0/1/U0     w-online      3     -1.00  2088   1   N
e448.c70c.96e7 80.17.150.29    C9/0/1/U3     w-online      4     -0.50  1785   0   N
e448.c70c.982b 80.17.150.18    C9/0/1/U2     w-online      5     0.00   1780   0   N
e448.c70c.9804 80.17.150.13    C9/0/1/U3     w-online      6     -0.50  1788   0   N
e448.c70c.9819 80.17.150.30    C9/0/1/U0     w-online      7     -1.00  1782   0   N
e448.c70c.980d 80.17.150.17    C9/0/1/U0     w-online      8     -1.00  1787   0   N

The following is a sample output of the show cable resiliency command when the impaired cable modems have recovered: 

Router# show cable resiliency 

              BG    Resil BG                                 RF
Resil BG I/F  ID    State          Count Time            Ctrl  Num
------------- ----- -------------- ----- --------------- ----------
Wi9/0/1:60    28989 Free           1     Jan 9  07:35:08
Wi9/0/1:61    28990 Free           1     Jan 9  07:36:54
Wi9/0/1:62    28991 Free           0

Excluding Cable Modems from Downstream Resiliency Operations

Table 7. Feature History

Feature Name

Release Information

Feature Description

Excluding Cable Modems from Downstream Resiliency Operations

Cisco IOS XE Dublin 17.12.1x

You can now exclude cable modems from Downstream Resiliency operations and move them to an exclusion list using the cable resiliency exclude command. Excluding cable modems ensures that RBG and NB are not used and the resiliency activity reduces. The exclusion list is stored on the SUP and you can use the show cable resiliency exclude to view the exclusion list.

By excluding cable modems, you can manage the downstream resiliency feature better and improve CPU efficiency. The following scenarios are examples of when you can use this feature and exclude cable modems from Downstream Resiliency operations.

  • Cable modems that report an excessive amount of impairment or recovery events, can be moved to the exclusion list. You can use the show cable resiliency counts command introduced in Cisco IOS XE Dublin 17.12.1x to identify which downstream channels and cable modems have the most impairments.

  • During planned maintenance windows, cable modems can be moved to the exclusion list.

Note

  • When adding cable modems to the exclusion list, if a cable modem is on RBG or NB, ensure that you keep it on RBG or NB unless the recovery cm-status event is received from the cable modem.

  • If you add a cable modem to the exclusion list and later physically disconnect the same cable modem, then ensure that you remove this cable modem from the exclusion list.

For cable modems in the exclusion list the Downstream resiliency behavior is as follows:

  • There is no action that is performed for cm-status impaired events. The cable modems remain in the w-online state with impairment.

  • Recovery cm-status events are handled as usual.

See:

Track Cable Modem Requests Which Move to RBG

Table 8. Feature History

Feature Name

Release Information

Feature Description

Support to Track Cable Modem Requests Which Move to RBG

Cisco IOS XE 17.18.1y

This feature enhances the existing show commands to display RBG requests counter regardless of whether the move is allowed or successful.

Commands Introduced:

  • show cable modem rbg-activity

  • show cable modem <MAC | IPv4 | IPv6> rbg-activity

  • show cable modem <cable interface> rbg-activity sort-by-rbg-requested

The RBG (Resiliency Bonding Group) Activity Monitoring feature provides enhanced visibility into how often Cable Modems (CMs) attempt to move to a Resiliency Bonding Group.

The cable resiliency cm-max-rbg-moves command allows operators to limit the number of times a CM can move to an RBG within a specified interval. Previously, once a CM reached this limit, further move attempts were denied, and there was no mechanism to track subsequent requests. This feature introduces a new counter, rbg_requested_count, which tracks every RBG request attempt, regardless of whether the move is accepted or denied. This provides operators with the necessary data to monitor CM behavior and troubleshoot connectivity issues effectively.

What:: This feature adds a new counter, rbg_requested_count, which tracks every attempt by a CM to move to an RBG, regardless of whether the move is successful or denied.

Why: The current implementation limits how frequently a CM can move to an RBG, but it does not provide visibility into how often a CM continues to request an RBG move after reaching that limit. This new counter helps operators monitor CM behavior and analyze persistent RBG move attempts beyond configured limits.

How: The system tracks these requests and provides visibility through enhanced CLI commands, allowing operators to see the request count and sort modems based on their RBG request frequency.

Benefits of Tracking Cable Modem Requests Which Move to RBG

  • Enhanced Operational Visibility: Provides clear data on how often modems attempt to recover via RBG.
  • Improved Debugging: Assists operators in analyzing persistent RBG move attempts and debugging RBG policies.
  • Identification of High-Frequency Modems: New sorting capabilities allow for quick identification of modems that are frequently attempting to recover using RBG.

Prerequisites of Tracking Cable Modem Requests Which Move to RBG

The cable resiliency feature must be in use, specifically the cable resiliency cm-max-rbg-moves <1-10> interval <1-65535> configuration.

Restrictions of Tracking Cable Modem Requests Which Move to RBG

  • The feature cannot be disabled.
  • If a CM is put into the DS resiliency exclusion list, the counter will not be incremented.

Operational Commands

A new column “Number of Times RBG requested" is added to the show cable modem rbg-activity command. Here is a sample output: 

router# show cable modem rbg-activity

                         Number of    Number of      Number of      CM At
                         Times RBG    Times Moved    RBG Created    cm-max-rbg-moves
I/F       MAC Address    Requested    To RBG         For This CM    Limit
-------------------------------------------------------------------------------------
C3/0/0 b42a.0e85.4421        1           0               0              no
C3/0/0 b42a.0e85.4859        1           0               0              no
C3/0/0 b42a.0e85.47e5        1           1               1              no
C3/0/0 b42a.0e85.4da1        2           1               1              no

A new column “Number of RBG requested for this CM" is added to the show cable modem < MAC | IPv4 | IPv6 > rbg-activity command. Here is a sample output: 

router# show cable modem b42a.0e85.4da1 rbg-activity

Number of RBG requested for this CM    : 2
Number of RBGs created for this CM      : 1
Total number of times moved to RBG      : 1

RBG Move History:

RBG WB:       Orig WB:      Timestamp:        RBG Created
--------------------------------------------------------------
Wi3/0/0:6     Wi3/0/0:0     May 28 04:01:40   yes

A new column “sort-by-rgb-requested " option is added to show cable modem < MAC | IPv4 | IPv6 > rbg-activity command. Here is a sample output: 

router# show cable modem c3/0/0 rbg-activity sort-by-rbg-requested

                        Number of   Number of    Number of      CM At
                        Times RBG   Times Moved  RBG Created    cm-max-rbg-moves
I/F    MAC Address      Requested   To RBG       For This CM    Limit
--------------------------------------------------------------------------------------------------------------
C3/0/0 b42a.0e85.40f1       4          3             3              no
C3/0/0 b42a.0e85.4da1       3          1             1              no
C3/0/0 b42a.0e85.47e5       2          2             2              no
C3/0/0 b42a.0e85.4859       1          0             0              no

If the sort-by-rbg-requested option is used, the Number of Times RBG Requested column displays in decending orders as shown in the above output.

Additional References

Related Documents

Related Topic

Document Title

Cisco CMTS Command Reference

http://www.cisco.com/c/en/us/td/docs/cable/cmts/cmd_ref/b_cmts_cable_cmd_ref.html

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for Downstream Resiliency Bonding Group


Note

The following table lists the software release in which a given feature is introduced. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Table 9. Feature Information for Downstream Resiliency Bonding Group

Feature Name

Releases

Feature Information

Downstream Resiliency Bonding Group

Cisco IOS XE Fuji 16.7.1

This feature was integrated on the Cisco cBR Series Converged Broadband Routers.

Resiliency Bonding Group Enhancement

Cisco IOS XE Gibraltar 16.12.1y

This feature was integrated on the Cisco cBR Series Converged Broadband Routers.