Troubleshooting guide

12-5
ATM and Layer 3 Switch Router Troubleshooting Guide
OL-1969-01
Chapter 12 Troubleshooting Layer 2 Interfaces
Troubleshooting Layer 2 Switching
Troubleshooting Layer 2 Switching
To troubleshoot a Layer 2 switching problems, use the following commands:
As stated before, once the first interface learns a new destination address, source address, and VLAN,
that information must be broadcasts to all other interfaces to allow them to update their CAM. That
information is broadcast using the Broute VC to communicate with ports on other modules in the same
bridge group. Figure 12-3 shows interface Fast Ethernet 0/0/0 using broadcast VC 0 to broadcast an
update (to the CAM) to interfaces Fast Ethernet 0/0/1 and 0/0/2.
Command Purpose
show bridge group Displays bridge group configuration and status
information.
show bridge Displays the status of all the bridge groups on the
switch router.
show spanning-tree number Displays the spanning tree topology for a bridge
group.
show interfaces bvi number Displays BVI interface configuration, status, and
statistics. Use this command when the BVI is part
of a bridge group.
show interfaces {fastethernet | gigabitethernet}
slot/subslot/port
(on the ingress interface)
Displays interface configuration, status, and
statistics on the ingress interface.
show interfaces {fastethernet | gigabitethernet}
slot/subslot/port
(on the egress interface)
Displays interface configuration, status, and
statistics on the egress interface.
show switch bridge-table entry Displays bridge table entry summary.
show epc freecam interface {fastethernet |
gigabitethernet} slot/subslot/port
Displays information about free space in the
content addressable memory.
show epc if-entry interface {fastethernet |
gigabitethernet} slot/subslot/port all
Displays all interface entry information for the
specific interface.
show epc patricia interface {fastethernet |
gigabitethernet} slot/subslot/port mac detail
(on the ingress interface)
Displays the MAC patricia tree for the ingress
interface.
show epc patricia interface {fastethernet |
gigabitethernet} slot/subslot/port mac detail
(on the egress interface)
Displays the MAC patricia tree for the egress
interface.