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Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
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Chapter 8 Configuring Spanning Tree
Using PVST+
2/4 1 not-connected 100 32 disabled
Configuring the PVST+ Port Priority
You can configure the port priority of switch ports in PVST+ mode. The port with the lowest priority
value forwards frames for all VLANs. The possible port priority value is 0–63. The default is 32. If all
ports have the same priority value, the port with the lowest port number forwards frames.
To configure the PVST+ port priority for a port, perform this task in privileged mode:
This example shows how to configure the PVST+ port priority for a port:
Console> (enable)
set spantree portpri 2/3 16
Bridge port 2/3 port priority set to 16.
Console> (enable)
show spantree 2/3
VLAN 1
.
.
.
Port Vlan Port-State Cost Prio Portfast Channel_id
------------------------ ---- ------------- --------- ---- -------- ----------
1/1 1 not-connected 4 32 disabled 0
1/2 1 not-connected 4 32 disabled 0
2/1 1 not-connected 100 32 disabled 0
2/2 1 not-connected 100 32 disabled 0
2/3 1 forwarding 19 16 disabled 0
2/4 1 not-connected 100 32 disabled 0
Configuring the PVST+ Default Port Cost Mode
If any switch in your network is using a port speed of 10 Gb or over and the network is using PVST+
spanning tree mode, all switches in the network must have the same path cost defaults. You can enter the
set spantree defaultcostmode
command to force all VLANs associated with all the ports to have the
same port cost default set.
Two default port cost modes are available—short and long.
•
The short mode has these parameters:
–
Portcost
–
Portvlancost (trunk ports only)
–
When uplinkfast is enabled, the actual cost is incremented by 3000
•
The long mode has these parameters:
–
Portcost
–
Portvlancost (trunk ports only)
–
When uplinkfast is enabled, the actual cost is incremented by 10,000,000
Task
Command
Step 1
Configure the PVST+ port priority for a
switch port.
set spantree portpri
mod/port
priority
Step 2
Verify the port priority setting.
show spantree
mod
/
port