Cisco Broadband Cable Command Reference Guide

Chapter 2 Cisco Cable Modem Termination System Commands
cable downstream channel-id
Syntax Description
OL-1581-05
cable downstream channel-id
To configure the downstream channel ID, use the cable downstream channel-id command in cable
interface configuration mode. To set the downstream channel ID to its default value, use the no form of
this command.
cable downstream channel-id id
no cable downstream channel-id
Defaults The unit number of the downstream device, starting with a value of 1.
Command Modes Interface configuration (cable interface only)
Command History
id Specifies a downstream channel ID. Valid values are from 0 to 255.
Release Modification
12.0(5)T This command was introduced.
Usage Guidelines Use this command to make sure that each downstream channel has a unique ID when there are multiple
Cisco CMTS routers at a headend facility.
Cisco IOS assigns the default ID number of each downstream channel in the order in which devices
connected to the downstream channels appear to the CMTS. The downstream channel connected to the
first device that appears to the CMTS is configured with a default ID of 1, the downstream channel
connected to the second device that appears is configured with an ID of 2, and so on.
Assigning default values in this manner guarantees unique values for all downstreams in a single
Cisco CMTS chassis. However, this does not guarantee unique channel IDs when more than one CMTS
exists on a network, so this command can be used to override the defaults and guarantee unique IDs.
Caution Changing the downstream channel ID of an active channel automatically disconnects all connected CMs
and forces them to reconnect.
Examples The following example shows how to configure the downstream channel on the cable interface line card
in slot 6 of a Cisco CMTS router with a channel ID of 44:
router(config-if)# cable downstream channel-id 44
The following example shows how to restore the downstream channel ID configuration to the default
configuration:
router(config-if)# cable downstream channel-id
Cisco Broadband Cable Command Reference Guide
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