Cisco UBR924 - uBR 924 Router Troubleshooting Tips page 61

debug cable-modem bridge
Use the debug cable-modem bridge command in privileged EXEC mode to debug bridge filter
processing information on a Cisco uBR924. To turn the debugging messages off, use the no form of
this command.
Syntax Description
This command has no keywords or arguments.
Defaults
No default behavior or values.
Command Modes
Privileged EXEC
Command History
Release
11.3 NA
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:
[no] debug cable-modem bridge
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
Modification
This command was first introduced.
Troubleshooting Tips for the Cisco uBR924 Cable Access Router 61
debug cable-modem bridge