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Catalyst 6500 Series Switch Command Reference—Release8.4
OL-6244-01
Chapter2 Catalyst 6500 Series Switch and ROM Monitor Commands show spantree
show spantree
To display spanning tree information for a VLAN or port, use the show spantree command.
show spantree [vlan] [active]
show spantree mod/port
Syntax Description
Defaults This command has no default settings.
Command Types Switch command.
Command Modes Normal.
Usage Guidelines If you do not specify the VLAN number, VLAN1 is displayed.
If you are in MISTP mode, instance information is not displayed.
The maximum length of the channel port list can be 47. The spaces in the Port(s) column may not be
enough to display the entire list in one line. If this is the case, the port list is split into multiple lines. For
example, in the following display, ports 6/5-8, 6/13, 6/15, 6/17, 6/19 are ch an nel ing :
...
Port(s) Vlan Port-State Cost Prio Portfast Channel_id
------------------------ ---- ------------- --------- ---- -------- ----------
6/5-8,6/13,6/15,6/17,6/1 1 not-connected 2684354 32 disabled 0
9
...
The LACP channel protocol does not support half-duplex links. If a port is in active/passive mode and
becomes half duplex, the port is suspended (and a syslog message is g en erate d). The p ort is sh own as
“connected” using the show port command and as “not connected” usi ng the show spantree command.
This discrepancy is because the port is physically connected but never joined spanning tree. To get the
port to join spanning tree, either set the duplex to full or set the channel mode to off for that port.
Examples This example (while in PVST+ mode) shows how to display the active spanning tree port configuration
for VLAN 1:
Console> (enable) show spantree 1 active
VLAN 1
Spanning tree mode PVST+
Spanning tree type ieee
Spanning tree enabled
vlan (Optional) Number of the VLAN; valid values are from 1 to 4094.
active (Optional) Displays only the active ports.
mod/port Number of the module and the port on the module.