Setting The Mistp-Pvst+ Mode Or Mistp Mode - Cisco WS-C2948G-GE-TX Configuration Manual

Chapter 7 Configuring Spanning Tree
Table 7-5
Feature
Hello time
Forward delay time

Setting the MISTP-PVST+ Mode or MISTP Mode

If you enable MISTP in a PVST+ network, you must be very careful to avoid bringing down the network.
This section explains how to enable MISTP or MISTP-PVST+ on your network.
If you have more than 4500 VLAN ports that are configured on your switch, your network could crash
Caution
if you change from MISTP to either PVST+ or MISTP-PVST+ mode. To avoid losing connectivity,
reduce the number of configured VLAN ports on your switch to no more than 4500.
Caution If you are working from a Telnet connection to your switch, the first time that you enable MISTP-PVST+
or MISTP mode, you must do so from the switch console. Do not use a Telnet connection through the
data port or you will lose the connection to the switch. Once you map a VLAN to an MISTP instance,
you can Telnet to the switch.
To change from PVST+ to MISTP-PVST+ or MISTP, perform this task in privileged mode:
Task
Set a spanning tree mode.
This example shows how to set a switch to MISTP-PVST+ mode:
Console> (enable) set spantree mode mistp-pvst+
PVST+ database cleaned up.
Spantree mode set to MISTP-PVST+.
Warning!! There are no VLANs mapped to any MISTP instance.
Console> (enable)
You can display VLAN-to-MISTP instance mapping information that is propagated from the root switch
at runtime. This display is available only in the MISTP or MISTP-PVST+ mode. When you are in
PVST+ mode, use the optional keyword config, to display the list of mappings that are configured on
the local switch.
MAC addresses are not displayed when you specify the keyword config.
Note
To display spanning tree mapping, perform this task in privileged mode:
Task
Step 1 Set spanning tree mode to MISTP.
Step 2 Show spanning tree mapping.
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Software Configuration Guide—Release 8.2GLX
78-15908-01
MISTP Mode Default Configuration (continued)
Default Value
2 sec
15 sec
Command
set spantree mode {mistp | pvst+ | mistp-pvst+}
Command
set spantree mode mistp
show spantree mapping [config]
Using MISTP-PVST+ or MISTP
7-31