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Table Of Contents
Cisco Dual DOCSIS Channel (DDC) on the Cisco uBR7246VXR Universal Broadband Router
Prerequisites for Cisco Dual DOCSIS Channel
Restrictions for Cisco Dual DOCSIS Channel
Information About Cisco Dual DOCSIS Channel
Introduction to Cisco DDC Redundancy
Hash Filters in Cisco DDC Redundancy
Cable Modem Classification in Cisco DDC Redundancy
Call Priority in Cisco DDC Redundancy
Active Emergency 911 Call Protection in Cisco DDC Redundancy
Active Voice Call Protection in Cisco DDC Redundancy
Cable Interface Bundling in Cisco DDC Redundancy
Configuring Cisco DDC Redundancy on the Cisco uBR7246VXR Universal Broadband Router
Switchover Methods for Cisco DDC Redundancy
Performing a Basic Switchover with Cisco DDC Redundancy
Performing a Revert-back Switchover with Cisco DDC Redundancy
Performing a Fast Switchover with Cisco DDC Redundancy
Performing a Route Reweighting Switchover with Cisco DDC Redundancy
Configuration Examples for Cisco DDC Redundancy
Example of Two Cisco uBR7246VXR Routers Being Configured
Example of Two Configured Cisco uBR7246VXR Routers
Example of Hash Filter for Two Cisco uBR7246VXR Routers
Example of DDC Cable Modem Classes for Two Configured Cisco uBR7246VXR Routers
Example of Active Call Status in Cisco DDC Redundancy
Example of Three Cisco uBR7246VXR Routers Configured for Cisco DDC
Verifying Cisco DDC Redundancy
Command Reference for Cisco DDC Redundancy
cable redundancy node {active | standby}
cable redundancy node frequency
Cisco Dual DOCSIS Channel (DDC) on the Cisco uBR7246VXR Universal Broadband Router
October 2004
Cisco IOS Release 12.3(9a)BC
Cisco IOS Release 12.3(9a)BC introduces Cisco Dual DOCSIS Channel (DDC) on the Cisco uBR7246VXR universal broadband router and all Cisco uBR7200 series cable interface line cards. This document describes the configuration and operation of Cisco DDC on the Cisco uBR7246VXR router.
Feature History for Cisco Dual DOCSIS Channel (DDC) on the Cisco uBR7246VXR Universal Broadband Router
12.3(9a)BC
This feature was introduced on the Cisco uBR7246VXR universal broadband router.
Finding Support Information for Platforms and Cisco IOS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.
Contents
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Prerequisites for Cisco Dual DOCSIS Channel
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Prerequisites for Cisco Dual DOCSIS Channel
The following prerequisites apply to Cisco DDC Redundancy with Cisco IOS Release 12.3(9a)BC:
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Restrictions for Cisco Dual DOCSIS Channel
The following restrictions apply to Cisco DDC Redundancy with Cisco IOS Release 12.3(9a)BC:
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Information About Cisco Dual DOCSIS Channel
This section contains the following topics:
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Introduction to Cisco DDC Redundancy
The Cisco DDC (Dual DOCSIS Channel) feature provides redundancy to cable voice and data customers by using two or three Cisco CMTS headends with connected RF upstreams and downstreams. Redundancy is provided by controlling on which Cisco CMTS the cable modems register, and by allowing movement of the cable modems between the Cisco CMTS systems. Cisco DDC provides redundancy during planned downtime, typically during software upgrades, with minimal configuration or control external to the Cisco CMTS.
Figure 1 illustrates one implementation of Cisco DDC redundancy using two Cisco CMTS headends (CMTS A and CMTSB). Cisco DDC Redundancy allows either CMTS headend to function as Target or Partner state for a given set of cable modems.
Figure 1 Cisco DDC Redundancy for DOCSIS 1.1 With Two Cisco uBR7246VXR Routers
In Figure 1, the downstreams and upstreams from each Cisco CMTS are combined onto one RF cable. This provides redundancy by enabling cable modem access to each Cisco CMTS at the same time. Straightforward management of cable modems is accomplished by controlling the downstream frequency for each cable modem. The following configuration examples describe the subinterface configuration for Cisco DDC redundancy that is illustrated in Figure 1.
Table 1 Cisco DDC Subinterface Configuration on the Cisco uBR7246VXR Routers for Figure 1
In this configuration, a group of cable modems are mapped to subinterface 5/0.1 and another group is mapped to subinterface 5/0.2. A hash filter creates the mapping based on the cable modems' MAC address.
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activeon CMTS A (target) and instandbyon CMTS B (partner).•
activeon CMTS B.When CMTS A is due for planned maintenance, the subinterface 5/0.1 on CMTS B is activated (switchover to
activestate), and then the subinterface 5/0.1 on CMTS A switches over tostandbystate. At this point, Cisco DDC sends messages to the cable modems in group A to move to CMTS B by locking on to the downstream frequency of interface 5/0 on CMTS B. During this movement, the cable modems are prioritized according to their subscribed services and the type of active calls they are carrying. The high priority cable modems are moved over first to minimize their potential downtime.After the cable modems are moved, the desired maintenance is performed. Once the maintenance is complete, the cable modems are moved back to their original states in a similar reversing procedure.
Hash Filters in Cisco DDC Redundancy
A hash filter is used to perform the following functions in Cisco DDC Redundancy:
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The one hash filter type available is named default. The hash filter can be customized by specifying a hash filter mask, specific OUIs, or specific MAC addresses.
During initial ranging, a hash-algorithm on the cable modems' MAC address is used to generate a value X. The value X identifies a group which is associated with one of the subinterfaces. If the subinterface corresponding to the cable modem group is not
activeon this CMTS, then the cable modem is moved to the target CMTS using a downstream frequency override.
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Cable Modem Classification in Cisco DDC Redundancy
Once a Cisco DDC switchover event takes place in planned maintenance, the routing information for corresponding IP subnets is switched and the cable modems on the original CMTS are no longer reachable by any IP packets. Until the cable modems reach the
ONLINEstate on the target Cisco CMTS, they briefly lose their IP connections.To minimize the downtime of the cable modems subscribed to the higher grade services, a DDC class value may be configured in the cable modem configuration file. Priority is given to the cable modems with high DDC class values during the switchover.
Cisco IOS 12.3(9a)BC introduces support for a new type-length value (TLV). This is added to the list of Cisco supported Vendor Specific TLVs to indicate the priority of a cable modem. You map a cable modem to a priority by including the desired priority TLV in the DOCSIS configuration file. Five priority values are available (the range is 0 - 4).
To include the DDC Priority in the DOCSIS configuration file, you must add the following elements for the cable modem:
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This is one illustration of the DOCSIS configuration file changes:
Type Length Value13 1 DDC PriorityBelow is an example of TLV 43, with subtype 8 (Cisco) and subtype 13 with a DDC priority of 4 in the plain text format of a DOCSIS configuration file:
43 (Vendor Specific Options)S08 (Vendor ID) = 00 00 0cS013 (DDC Priority) = 04Call Priority in Cisco DDC Redundancy
During a Cisco DDC switchover event, Cisco IOS examines all the active service flows and marks cable modems with high priority flows. High priority flows are defined as UGS, UGS_AD, RTPS and NRPTS flows. For cable modems with the same DDC class (as described in the "Cable Modem Classification in Cisco DDC Redundancy" section), the cable modems marked as having active high priority flows are switched before those without high priority flows. Because service flows are created and deleted dynamically, this component of cable modem priority changes with time.
Active Emergency 911 Call Protection in Cisco DDC Redundancy
Active emergency 911 (E911) calls have utmost and highest priority and every effort should be made to prevent loss of service during a call, and to restore any lost service as quickly as possible.
Like the active UGS flows category, E911 calls are a dynamic indicator. At any time you can determine if there are active E911 calls by examining the cable modems. If a cable modem with an active E911 call is found, the request for Cisco DDC switchover is immediately halted and a message displays that notifies you about the existence of an active E911 call.
In this circumstance, you can attempt another Cisco DDC switchover event later, or force a switchover with an additional CLI command parameter.
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Active Voice Call Protection in Cisco DDC Redundancy
Clearly it is preferable that voice calls do not experience significant interruptions. When a Cisco DDC switchover event is attempted, the number of voice calls is counted. If this number exceeds a threshold (that you can configure), a message is displayed and the Cisco DDC switchover event is aborted. In this circumstance, you can attempt another DDC switchover event later, or force a switchover with an additional cable redundancy node {active | standby} command with the force option.
Cable Interface Bundling in Cisco DDC Redundancy
When interface bundling is used to share IP subnets across multiple MAC domains and to help conserve IP addresses, IP configuration commands are used on the bundle master and distributed to the bundle slaves. Because Cisco DDC Redundancy deals with groups of cable modems and IP subnets, Cisco DDC commands are configured on the bundle master interfaces and distributed to the bundle slaves.
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Configuring Cisco DDC Redundancy on the Cisco uBR7246VXR Universal Broadband Router
Each Cisco CMTS that participates in the redundancy scheme must be configured with the total number of CMTS headends that have their RF channels connected together, and a unique identifier MYID. Subinterfaces must be configured on each interface or interface bundle master that participates in the DDC Redundancy scheme. Each subinterface is associated with a group of cable modems by the hash filter used on this interface or bundle. Finally, each subinterface is put in either active (target) or
standby(partner) state.Additional configuration requirements for Cisco DDC Redundancy described in this procedure include the following:
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Perform the steps in this procedure to enable Cisco DDC Redundancy on each Cisco uBR7246VXR router in the redundancy scheme.
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Prerequisites
To complete this procedure, you must have the following information prepared for each router in the Cisco DDC Redundancy scheme.
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SUMMARY STEPS
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DETAILED STEPS
Step 1
enable
Example:Router> enable
Enables privileged EXEC mode.
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Step 2
configure terminal
Example:Router# configure terminal
Enters global configuration mode.
Step 3
cable redundancy myid node_id nodes nodes
Example:Router# cable redundancy myid 2 nodes 3
Specifies the total number of Cisco CMTS systems participating in the DDC Redundancy scheme and the ID of this particular Cisco CMTS.
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Step 4
cable redundancy hashfilter hash_id {type namestring | mac-mask mac-mask | mac-map mac-address node node_id | oui-map oui node node_id}
Example:Router# cable redundancy hashfilter 1 type default
Router# cable redundancy hashfilter 1 macmask FFFF.FF00.0000
Router# cable redundancy hashfilter 1 macmap 0007.0e03.68ad node 2
Router# cable redundancy hashfilter 1 ouimap 00070e node 1
Specifies the mapping of the CMTS MAC addresses and nodes on the local system, to be used by all DDC nodes (routers) participating in the scheme.
The hash filter can be customized by specifying a hash filter mask, specific OUIs, or specific MAC addresses. The MAC address or OUI map is shared and hashed by all Cisco DDC nodes.
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Step 5
interface cable slot/port
Example:Router# interface cable 3/0
Enters interface configuration mode for the specified slot and port.
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Step 6
cable redundancy hashfilter hash_id
Example:Router(config-if)# cable redundancy hashfilter 1
Enables hash filtering on the specified cable interface or bundle. If the command is executed on a bundle master, the hash filtering is enabled on all bundle members.
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Step 7
cable redundancy node node_id frequency frequency
Example:Router(config-if)# cable redundancy node 1 frequency 435000000
Defines downstream frequencies for each node participating in the scheme other than the current Cisco CMTS. This frequency is used to switch cable modems to the downstream frequency of the backup interface (on another Cisco CMTS) via DFO and DCC messages.
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Step 8
cable redundancy target node_id
Example:Router(config-if)# cable redundancy target 1
Defines the target node and therefore the downstream frequency to use in a DDC switchover event, as configured by the previous step.
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When this command is not present, the default target node is the next higher node in the scheme (the next higher node_id value in the scheme). For example, if there are three participating nodes, the default target nodes are as follows (respectively):
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Step 9
cable redundancy threshold max-calls
Example:Router(config-if)# cable redundancy threshold 20
Specifies the active voice call threshold. If the number of active voice calls exceeds this value, the DDC switchover does not take place, unless it is forced by using the cable redundancy node node_id standby force subinterface configuration command (Step 11).
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Step 10
interface cable slot.subinterface
Example:Router(config-if)# interface cable 3.01
Enters (sub)interface configuration mode for the specified slot and subinterface.
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Step 11
cable redundancy node node_id {active | standby [force]}
Example:Router(config-subif)# cable redundancy node 2 active
Router(config-subif)# cable redundancy node 1 standby
Router(config-subif)# cable redundancy node 1 standby force
Specifies with which node ID this subinterface is associated, and in what state it is to be. The force keyword forces the subinterface into the standby state regardless of the number of voice calls or active E911 calls.
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Step 12
Router(config-if)# Ctrl^Z
When you have completed the configuration, enter ^Z (Control key with Z) to exit configuration mode and return to privileged EXEC.
Switchover Methods for Cisco DDC Redundancy
Cisco DDC Redundancy enables you to perform multiple types of switchover events according to your needs. These switchover methods are described with the following procedures:
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Performing a Basic Switchover with Cisco DDC Redundancy
In this switchover procedure, there are two DDC nodes (routers), and cable 3/0 is the master on both. All cable modems from one system (CMTS B) are moved to another system (CMTS A).
Prerequisites
In this procedure, all downstreams are bundled on their respective systems.
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active(target) state and cable 3/0.2 instandby(partner) state.•
active(target) and cable 3/0.1 instandby(partner) state.SUMMARY STEPS
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Perform the following steps on CMTS A (node 1)
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Perform the following steps on CMTS B (node 2)
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Perform the following step on both CMTS A (node 1) and CMTS B (node 2).
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DETAILED STEPS
Performing a Revert-back Switchover with Cisco DDC Redundancy
There are two different approaches to the reverting process. The flow of commands is listed in this topic for both cases.
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The reason for the two different approaches is that subinterface cable 3/0.2 on CMTS B has a higher routing preference than on CMTS A. As soon as the cable redundancy node 2 active command is executed on CMTS B, IP connectivity for the node 2 cable modems on CMTS A is lost. As long as the associated cable redundancy node 2 standby command is executed immediately on CMTS A, the impact is minimal.
However, this also requires that the show cable redundancy calls be executed on CMTS A before the switchover event is started. This verifies that no E911 calls are in progress, and that the total number of calls on cable 3/0.2 on CMTS A is lower than the threshold.
The method that changes the route preferences does not run the risk of accidental termination of E911 calls, and it does not add the additional time between the cable redundancy node standby and active commands to the total outage time for the cable modems. It does, however, increase the total number of configuration changes.
Performing a Fast Switchover with Cisco DDC Redundancy
Read the following instructions and understand them completely prior to their execution. The steps below should be executed in succession as quickly as possible.
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Within 20 seconds, modems will begin arriving on CMTS-B.
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Performing a Route Reweighting Switchover with Cisco DDC Redundancy
Read the following instructions and understand them completely prior to their execution.
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Within 20 seconds, modems begin to arrive on CMTS B.
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Configuration Examples for Cisco DDC Redundancy
Example of Two Cisco uBR7246VXR Routers Being Configured
This sample configuration is for a basic Cisco DDC Redundancy scheme. These are the primary features of this configuration are as follows:
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This example assumes that there is a routing protocol running on the WAN interfaces to carry route updates about the cable interface states. The numeration for the steps below differs from the numeration described in the "Configuring Cisco DDC Redundancy on the Cisco uBR7246VXR Universal Broadband Router" section. However, the sequence of configuration modes and commands is essentially the same.
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Global Configuration
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Interface Configuration on cable 3/0
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Subinterface Configuration on cable 3/0.1
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Subinterface Configuration on cable 3/0.2
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Example of Two Configured Cisco uBR7246VXR Routers
The following example of the show cable redundancy command illustrates DDC redundancy with two Cisco uBR7246VXR routers. This example is from DDC Node ID 1 (one of two).
Router# show cable redundancyNumber of participating nodes: 2DDC ID: 1Number of hash filters: 3Int/Bundle HashID VoiceThresholdBundle 1 3 6*Cable3/0Cable3/1Cable4/0Cable4/1Cable5/0Cable5/1Cable6/0Cable6/1* indicates bundle masterSubInterface Node Status LineStateCable3/0.1 1 active upCable3/0.2 2 standby downIn this example, there are two Cisco routers participating in the DDC Redundancy configuration and the node_ID of the current router is 1. There are three configured hash filters. All the interfaces are part of a bundle interface with cable3/0 being the bundle master. Hash Filter 3 is associated with this bundle interface. The voice call threshold is set to 6.
This example also illustrates the association of the node_IDs to the subinterface, along with the current subinterface state.
Example of Hash Filter for Two Cisco uBR7246VXR Routers
The following example of the show cable redundancy hashfilter command illustrates the same DDC Redundancy scheme (two Cisco uBR7246VXR routers). This command displays the configured hash filter parameters. You can either list all hash filters (as shown) or list one hash filter, if specified with the optional hash_id value at the end of the command.
Router# show cable redundancy hashfilterHashFilter 1HashType MacMaskdefault ffff.ffff.ffffMacAddr OUI Node0000.39cc.b270 10000.39cc.ba70 20000.39cc.c070 2HashFilter 2HashType MacMaskdefault 0000.00ff.ffffMacAddr OUI Node00.00.39 100.08.0D 100.0C.E5 1Example of DDC Cable Modem Classes for Two Configured Cisco uBR7246VXR Routers
The following example of the show cable redundancy class command displays the number of cable modems in each DDC class of the same DDC Redundancy scheme (two Cisco uBR7246VXR routers).
Router# show cable redundancy classNumber of modems in each DDC class:Interface Class0 Class1 Class2 Class3 Class4Cable3/0 32 0 0 0 0Cable3/1 32 0 0 0 0Cable4/0 32 0 0 0 0Cable4/1 0 0 0 0 0Cable5/0 31 0 0 0 0Cable5/1 32 0 0 0 0Cable6/0 0 0 0 0 0Cable6/1 0 0 0 0 0Example of Active Call Status in Cisco DDC Redundancy
The following example of the show cable redundancy calls command displays the number of active 911 (E911) calls, voice calls, and the number of cable modems with service flows for each subinterface. If the subinterface is configured on a bundle, the number of calls is the total for all the members in the bundle.
Router# show cable redundancy callsSubInterface 911Calls VoiceCalls ModemCount ServiceFlowCable3/0.1 0 0 159 159Cable3/0.2 0 0 0 0Example of Three Cisco uBR7246VXR Routers Configured for Cisco DDC
The following example illustrates one DDC Redundancy scheme with three Cisco uBR7246VXR chassis (CMTS A, CMTS B, CMTS C). CMTS C is the Standby router (node) in this configuration.
CMTS-A Configuration Example
cable redundancy myid 1 nodes 3cable redundancy hashfilter 1 type hash-defaultinterface cable3/0cable bundle 1 mastercable redundancy hash-filter 1cable redundancy node 2 frequency 550000000cable redundancy node 3 frequency 540000000interface cable3/0.1ip address 1.1.1.1 255.255.255.0ip address 2.2.2.2 255.255.255.0 secondarycable redundancy node 1 activeinterface cable3/0.2ip address 3.3.3.3 255.255.255.0ip address 4.4.4.4 255.255.255.0 secondarycable redundancy node 2 standbyinterface cable3/0.3ip address 5.5.5.5 255.255.255.0ip address 6.6.6.6 255.255.255.0 secondarycable redundancy node 3 standbyCMTS-B Configuration Example
cable redundancy myid 2 nodes 3cable redundancy hashfilter 1 type hash-defaultinterface cable3/0cable bundle 1 mastercable redundancy hash-filter 1cable redundancy node 1 frequency 530000000cable redundancy node 3 frequency 540000000interface cable3/0.1ip address 1.1.1.1 255.255.255.0ip address 2.2.2.2 255.255.255.0 secondarycable redundancy node 1 standbyinterface cable3/0.2ip address 3.3.3.3 255.255.255.0ip address 4.4.4.4 255.255.255.0 secondarycable redundancy node 2 activeinterface cable3/0.3ip address 5.5.5.5 255.255.255.0ip address 6.6.6.6 255.255.255.0 secondarycable redundancy node 3 standbyCMTS-C Configuration Example
cable redundancy myid 3 nodes 3cable redundancy hashfilter 1 type hash-defaultinterface cable3/0cable bundle 1 mastercable redundancy hash-filter 1cable redundancy node 1 frequency 530000000cable redundancy node 2 frequency 550000000interface cable3/0.1ip address 1.1.1.1 255.255.255.0ip address 2.2.2.2 255.255.255.0 secondarycable redundancy node 1 standbyinterface cable3/0.2ip address 3.3.3.3 255.255.255.0ip address 4.4.4.4 255.255.255.0 secondarycable redundancy node 2 standbyinterface cable3/0.3ip address 5.5.5.5 255.255.255.0ip address 6.6.6.6 255.255.255.0 secondarycable redundancy node 3 activeWhat to Do Next
See the "Verifying Cisco DDC Redundancy" section.
Verifying Cisco DDC Redundancy
Prerequisites
Complete the "Configuring Cisco DDC Redundancy on the Cisco uBR7246VXR Universal Broadband Router" section on each router in the Cisco DDC Redundancy scheme prior to verification.
SUMMARY STEPS
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DETAILED STEPS
Additional References
The following sections provide references related to <<Feature>>.
Related Documents
Cable Interface Features for the Cisco CMTS Relating to Cisco DDC Redundancy
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http://www.cisco.com/univercd/cc/td/doc/product/cable/cab_rout/cmtsfg/ufg_bund.htm
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http://www.cisco.com/en/US/docs/ios/cable/command/reference/cbl_12_d_to_h.html#wp1115329
Cisco IOS Software for Broadband Cable
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http://www.cisco.com/en/US/docs/ios/cable/command/reference/cbl_book.html
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http://www.cisco.com/en/US/docs/cable/cmts/ubr7200/release/notes/12_3bc/123BCu72.html
Cisco Broadband Cable Technical Support
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http://www.cisco.com/en/US/tech/tk86/tk804/technologies_q_and_a_item09186a0080134f1d.shtml
Cisco uBR7246VXR Universal Broadband Router
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http://www.cisco.com/en/US/docs/cable/cmts/ubr7200/installation/guide/ub72khig.html
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http://www.cisco.com/univercd/cc/td/doc/product/cable/cab_rout/cr72scg/index.htm
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http://www.cisco.com/univercd/cc/td/doc/product/cable/cab_rout/13536upg.htm
Standards
DOCSIS
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http://www.cisco.com/en/US/tech/tk86/tk168/technologies_q_and_a_item09186a0080174789.shtml
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MIBs
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To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
Technical Assistance
Command Reference for Cisco DDC Redundancy
This section describes configuration and show commands for Cisco DDC Redundancy on the Cisco uBR7246VXR router, as supported by Cisco IOS Release 12.3(9a)BC and later releases in this train.
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cable redundancy hashfilter
To set the MAC address and DDC node mappings of the DDC redundancy scheme, use the cable redundancy hashfilter command in global configuration mode. This hash filter is to be shared by all DDC nodes (routers) in the redundancy scheme. To remove the hash filter from the Cisco CMTS router, use the no form of this command.
cable redundancy hashfilter hash_id {type namestring | mac-mask mac-mask | mac-map mac-address node node_id | oui-map oui node node_id}
no cable redundancy hashfilter
Syntax Description
Defaults
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Command Modes
Global configuration
Command History
Release 12.3(9a)BC
This command was introduced on the Cisco uBR7246 universal broadband router.
Usage Guidelines
Note
This command is used in the early stages of configuring DDC Redundancy on all DDC nodes (routers) in the scheme. For additional information in context, refer to the "Configuring Cisco DDC Redundancy on the Cisco uBR7246VXR Universal Broadband Router" section.
Examples
The following example implements the cable redundancy hashfilter command in four sequential steps, completing the entire mapping information required for one DDC node in a redundancy scheme of two routers:
Router# cable redundancy hashfilter 1 type defaultRouter# cable redundancy hashfilter 1 macmask FFFF.FF00.0000Router# cable redundancy hashfilter 1 macmap 0007.0e03.68ad node 2Router# cable redundancy hashfilter 1 ouimap 00070e node 1Related Commands
cable redundancy myid
To set the total number of Cisco DDC nodes (routers) in the DDC Redundancy scheme, and to set the ID of the current DDC node, use the cable redundancy myid command in global configuration mode. To remove a DDC node ID from the router, use the no form of this command.
cable redundancy myid node_id nodes nodes
no cable redundancy myid node_id
Syntax Description
Defaults
DDC Redundancy is disabled and DDC nodes (routers) are not configured for DDC redundancy by default.
Command Modes
Global configuration
Command History
Release 12.3(9a)BC
This command was introduced on the Cisco uBR7246 universal broadband router.
Usage Guidelines
This configuration must be present (identical except node_id) on all DDC nodes (routers) participating in the scheme.
This command is used in the early stages of configuring DDC Redundancy on all DDC nodes (routers) in the scheme. For additional information in context, refer to the "Configuring Cisco DDC Redundancy on the Cisco uBR7246VXR Universal Broadband Router" section.
Examples
The following example configures the DDC node (router) ID to be 2 in a scheme in which there are three DDC nodes total.
Router# cable redundancy myid 2 nodes 3
Related Commands
Configures the DDC node (node_id) with active or standby state.
Displays the current DDC redundancy configurations and status.
cable redundancy node {active | standby}
To set the DDC node (router) with which a subinterface is associated, and to set the state for that interface, use the cable redundancy node {active | standby} command in subinterface configuration mode. To remove this configuration from the router, use the no form of this command.
cable redundancy node node_id {active | standby} [force]
no cable redundancy node node_id {active | standby}
Syntax Description
Defaults
DDC switchover events are disabled by default and must be manually initiated on a case-by-case basis.
Command Modes
Subinterface configuration
Command History
Release 12.3(9a)BC
This command was introduced on the Cisco uBR7246 universal broadband router.
Usage Guidelines
This command can be used in the context of DDC configuration, testing or forced switchover events. Refer to earlier procedures in this document for additional information.
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Examples
The following command sequence sets the DDC node states in a scheme with two DDC nodes (routers), then forces a switchover event on DDC node 1 that puts it into
standbystate.Router(config-subif)# cable redundancy node 2 active
Router(config-subif)# cable redundancy node 1 standby
Router(config-subif)# cable redundancy node 1 standby force
Related Commands
cable redundancy node frequency
To set the downstream frequencies for each node participating in the scheme other than the current DDC node (router), use the cable redundancy node frequency command in interface configuration mode. This frequency is used to switch cable modems to the downstream frequency of the backup interface (on another DDC node) via DFO and DCC messages. To remove this setting from the router, use the no form of this command.
cable redundancy node node_id frequency frequency
no cable redundancy node node_id frequency
Syntax Description
node_id
DDC target node ID for which the frequency is being set
frequency
Downstream frequency of the target interface
Defaults
Cable downstream frequency override is enabled by default.
Command Modes
Interface configuration mode
Command History
Release 12.3(9a)BC
This command was introduced on the Cisco uBR7246 universal broadband router.
Usage Guidelines
This command must be present on each cable interface participating in the scheme, regardless of its bundle status.
Examples
The following example configures the downstream frequency of DDC node 1 to be 435000000.
Router(config-if)# cable redundancy node 1 frequency 435000000
Related Commands
cable redundancy target
To set the target DDC node (router) to use in a DDC switchover event, use the cable redundancy target command in interface configuration mode. To remove this configuration from the router, use the no form of this command.
cable redundancy target node_id
no cable redundancy target node_id
Syntax Description
Defaults
When this command is not present, the default target node is the next higher node in the scheme.
Command Modes
Interface configuration
Command History
Release 12.3(9a)BC
This command was introduced on the Cisco uBR7246 universal broadband router.
Usage Guidelines
The downstream frequency that is used in a DDC switchover event is the frequency set on the respective target DDC node, as set with this command.
Note
When this command is not present, the default target node is the next higher node in the scheme (the next higher node_id value in the scheme). For example, if there are three participating nodes, the default target nodes are as follows (respectively):
•
•
•
Examples
The following example configures the target node on the current router to be DDC node 1, often referred to as CMTS A in additional sections of this document.
Router(config-if)# cable redundancy target 1
Related Commands
cable redundancy threshold
To set the active voice call threshold on the current DDC node (router), use the cable redundancy threshold command in interface configuration mode. If the number of active voice calls exceeds this value, a DDC switchover does not take place unless it is forced by using the cable redundancy node node_id standby force subinterface configuration command. To remove this configuration from the router, use the no form of this command.
cable redundancy threshold max-calls
no cable redundancy threshold
Syntax Description
Defaults
The threshold for maximum calls is not set by default.
Command Modes
Interface configuration
Command History
Release 12.3(9a)BC
This command was introduced on the Cisco uBR7246 universal broadband router.
Usage Guidelines
If the command is configured on a bundle master, the threshold is used to compare with the total number of voice calls in the bundle. This command is not accepted on interfaces configured as bundle slaves.
If this threshold is not configured, this check does not occur and the DDC switchover proceeds regardless of how many voice calls are active. This is subject to additional constraints described in the "Call Priority in Cisco DDC Redundancy" section.
Examples
The following example configures DDC redundancy not to take place if there are more than 20 active or E911 calls at the time a DDC switchover event is attempted or requested.
Router(config-if)# cable redundancy threshold 20
Related Commands
show cable redundancy
To display the DDC redundancy partners and their relative states, and additional information about DDC states on the Cisco CMTS, use the show cable redundancy command in privileged EXEC mode.
show cable redundancy {hashfilter | class | calls}
Syntax Description
Defaults
This command has no default behaviors or values.
Command Modes
Privileged EXEC
Command History
Release 12.3(9a)BC
This command was introduced on the Cisco uBR7246 universal broadband router.
Examples
The following example of the show cable redundancy hashfilter command illustrates the same DDC Redundancy scheme (two Cisco uBR7246VXR routers). This command displays the configured hash filter parameters. You can either list all hash filters (as shown) or list one hash filter, if specified with the optional hash_id value at the end of the command.
Router# show cable redundancy hashfilterHashFilter 1HashType MacMaskdefault ffff.ffff.ffffMacAddr OUI Node0000.39cc.b270 10000.39cc.ba70 20000.39cc.c070 2HashFilter 2HashType MacMaskdefault 0000.00ff.ffffMacAddr OUI Node00.00.39 100.08.0D 100.0C.E5 1The following example of the show cable redundancy class command displays the number of cable modems in each DDC class of the same scheme (two Cisco uBR7246VXR routers).
Router# show cable redundancy classNumber of modems in each DDC class:Interface Class0 Class1 Class2 Class3 Class4Cable3/0 32 0 0 0 0Cable3/1 32 0 0 0 0Cable4/0 32 0 0 0 0Cable4/1 0 0 0 0 0Cable5/0 31 0 0 0 0Cable5/1 32 0 0 0 0Cable6/0 0 0 0 0 0Cable6/1 0 0 0 0 0The following example of the show cable redundancy calls command displays the number of active 911 (E911) calls, voice calls, and the number of cable modems with service flows for each subinterface. If the subinterface is configured on a bundle, the number of calls is the total for all the members in the bundle.
Router# show cable redundancy callsSubInterface 911Calls VoiceCalls ModemCount ServiceFlowCable3/0.1 0 0 159 159Cable3/0.2 0 0 0 0Related Commands
Glossary
DCC
Dynamic Channel Change, as described by the CableLabsR Data-Over-Cable Service Interface Specifications 1.1 & 2.0 RFI Acceptance Test Plan, CM-TP-RFI-ATP-I05-040618:
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DDC
Dual-DOCSIS Channel. A high availability redundancy scheme with two or more Cisco uBR7246VXR routers. Redundancy is provided by controlling on which Cisco CMTS the cable modems register, and by allowing movement of the cable modems between the Cisco CMTS systems.
DFO
Downstream Frequency Override
DOCSIS
Data Over Cable Service Interface Specification, published by CableLabsR:
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EMTA
Embedded Media Terminal Adapter. MTA integrated with a cable modem.
IUC
Interval Usage Code. A field in MAPs and UCDs to link burst profiles to grants.
MAP
Bandwidth Allocation MAP.
MIB
Management Information Base. A database of network management information that is used and maintained by a network management protocol, such as SNMP or CMIP. MIB objects are organized in a tree structure that includes public (standard) and private (proprietary) branches.
MTA
Multimedia terminal adapter. A CPE device that implements DCS or NCS signaling and provides an interface that allows customer equipment to access PacketCable services.
PCMM
PacketCable Multimedia.
SNMP
Simple Network Management Protocol. Network management protocol used almost exclusively in TCP/IP networks.
SNR
Signal to Noise Ratio. The ratio of Signal Power to Noise Power in the defined measurement bandwidth.
TLV
Type/Length/Value. A three-part object in the DOCSIS configuration file that governs part of cable modem provisioning on the Cisco CMTS. DOCSIS 1.1 TLVs include service flow encodings, classifier encodings, and support for PHS rules. The Cisco CMTS TLV parser features are used by different MAC message modules.
UCD
Upstream Channel Descriptor. The Cisco CMTS periodically broadcasts Upstream Channel Descriptor (UCD) messages to all cable modems. These messages define upstream channel characteristics including upstream frequencies, symbol rates and modulation schemes, FEC parameters, and other physical layer values.
Upstream
The direction of transmission from the subscriber to the head-end in a cable television network.
Copyright © 2004 Cisco Systems, Inc. All rights reserved.
