Cisco Systems UBR900 User Manual

 Configuring the Cisco uBR900 Series Cable Access Routers 121

Use the debug cable-modem bridge command in privileged EXEC mode to debug bridge filter 
processing information on a Cisco uBR900 series. To turn the debugging messages off, use the no 
form of this command.

[no] debug cable-modem bridge

Syntax Description

This command has no keywords or arguments.

Defaults

No default behavior or values.

Command Modes

Privileged EXEC 

Command History

Usage Guidelines

When the interface is down, all bridge table entries learned on the Ethernet interface are set to discard 
because traffic is not bridged until the cable interface has completed initialization. After the interface  
(the line protocol) is completely up, bridge table entries learned on the Ethernet interface program 
the cable MAC data filters. The cable MAC hardware filters out any received packets whose 
addresses are not in the filters. In this way, the cable interface only receives packets addressed to its 
own MAC address or an address it has learned on the Ethernet interface.

Examples

The following example shows sample display output for the debug cable-modem bridge privileged 
EXEC command:

uBR924# debug cable-modem bridge

%LINEPROTO-5-UPDOWN: Line protocol on Interface cable-modem0, changed state to downshut

cm_tbridge_add_entry(): MAC not initialized, discarding entry: 00e0.fe7a.186fno shut

cm_tbridge_add_entry(): MAC not initialized, discarding entry: 00e0.fe7a.186f

%LINEPROTO-5-UPDOWN: Line protocol on Interface cable-modem0, changed state to up

cm_tbridge_add_entry(): Adding entry 00e0.fe7a.186f to filter 2

11.3 NA

This command was introduced.