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Catalyst 6500 Series Switch Command Reference—Release7.6
78-15328-01
Chapter2 Catalyst 6500 Series Switch and ROM Monitor Commands set spantree mode
If you chang e the spanning tree mode from PVST+ to MISTP or MISTP to PVST+, the STP mode
previously running stops, all the information collected at runtime is used to build the port database for the
new mode, and the new STP mode restarts the computation of the active topology from zero. All the
parameters of the previous STP per VLAN or per instance are kept in NVRAM.
If you change the spanning tree mode from PVST+ to MISTP or MISTP to PVST+ and Backbone Fast is
enabled, this message is displayed:
Console> (enable) set spantree mode mistp
Cannot change the spantree mode to MISTP when backbonefast is enabled.
Examples This example sh ows how to se t th e spanning tree mode t o PV ST + :
Console> (enable) set spantree mode pvst+
Warning!! Changing the STP mode from a telnet session might disconnect the session.
Do you want to continue [n]? y
Spantree mode set to PVST+.
Console> (enable)
This example shows what happens if you change the spanning tree mode from PVST+ to MISTP:
Console> (enable) set spantree mode mistp
Warning!! Changing the STP mode from a telnet session will disconnect the session because
there are no VLANs mapped to any MISTP instance.
Do you want to continue [n]? y
Console> (enable)
This example shows how to set the spanning tree mode to MST:
Console> (enable) set spantree mode mst
Warning!! Changing the STP mode from a telnet session will disconnect the sessi
n because there are no VLANs mapped to any MISTP instance.
Do you want to continue [n]? y
Console> (enable)
This example shows how to set the spanning tree mode to rapid PVST+:
Console> (enable) set spantree mode rapid-pvst+
Warning!! Changing the STP mode from a telnet session might disconnect the session.
Do you want to continue [n]? y
Console> (enable)
Related Commands se t v lan
show spantree