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Chapter 11
Troubleshooting Switched Ethernet
show vtp domain
The VLAN Trunk Protocol (VTP) is designed to simplify the introduction of
VLANs in multi-switch networks. Within the management domain, a new
VLAN is only specified once, and the configuration is propagated throughout
the network. The configuration information includes the parameters needed
for differing topologies within the switched network.
The show vtp domain command provides the following status information.
Note that VTP updates are sent over VLAN 1 when troubleshooting VTP issues.
Switch_A> (enable) show vtp domain
Domain Name Domain Index VTP Version
Local Mode Password
-------------------------------- ------------ -----------
------------ --------
Global 1 2
Transparent -
Vlan-count Max-vlan-storage Config Revision Notifications
---------- ---------------- --------------- -------------
5 1023 0 enabled
Last Updater V2 Mode Pruning PruneEligible on Vlans
--------------- -------- -------- ------------------------
-
10.1.2.20 disabled disabled 2-1000
show cam
Switches operate at Layer 2 of the OSI model, so MAC addresses are the basis
for forwarding decisions. Although VLANs are typically assigned on Layer 3
boundaries, the switch directs unicast frames in the same manner as a bridge.
The show cam command reports the MAC address associated with the ports
of the switch, as follows. Note the specifications that must be included with the
command in the first output, followed by the actual MAC list in the second.
Switch_A> (enable) show cam
Usage: show cam [count] <dynamic|static|permanent|system>
[vlan]
show cam <dynamic|static|permanent> <mod_num/port_
num>
show cam <mac_addr> [vlan]
show cam agingtime
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