8-27
Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
78-13315-02
Chapter 8 Configuring Spanning Tree
Using MISTP-PVST+ or MISTP
This example shows how to configure the port priority and verify the configuration:
Console> (enable)
set spantree portpri 2/12 40
Bridge port 2/12 port priority set to 40.
Console> (enable)
show spantree mistp-instance 1
Instance 1
Spanning tree mode MISTP-PVST+
Spanning tree type ieee
Spanning tree instance enabled
Designated Root 00-d0-00-4c-18-00
Designated Root Priority 32769 (root priority: 32768, sys ID ext: 1)
Designated Root Cost 0
Designated Root Port none
VLANs mapped: 6
Root Max Age 20 sec Hello Time 2 sec Forward Delay 15 sec
Bridge ID MAC ADDR 00-d0-00-4c-18-00
Bridge ID Priority 32769 (bridge priority: 32768, sys ID ext: 1)
VLANs mapped: 6
Bridge Max Age 20 sec Hello Time 2 sec Forward Delay 15 sec
Port Inst Port-State Cost Prio Portfast Channel_id
------------------------ ---- ------------- --------- ---- -------- ----------
2/12 1 forwarding 22222222 40 disabled 0
Console> (enable)
Configuring the MISTP Port Instance Cost
You can configure the port instance cost for an instance of MISTP or MISTP-PVST+. Ports with a lower
instance cost are more likely to be chosen to forward frames. You should assign lower numbers to ports
attached to faster media (such as full duplex) and higher numbers to ports attached to slower media. The
default cost differs for different media. The possible value for port instance cost is 1–268435456.
To configure the port instance cost for a port, perform this task in privileged mode:
This example shows how to configure the MISTP port instance cost on a port:
Console> (enable)
set spantree portinstancecost 2/12 cost 110110 2
Port 2/12 instances 1,3-16 have path cost 22222222.
Port 2/12 instances 2 have path cost 110110.
Console> (enable)
Configuring the MISTP Port Instance Priority
You can set the port priority for an instance of MISTP. The port with the lowest priority value for a
specific MISTP instance forwards frames for that instance. The possible port instance range is 0–63. If
all ports have the same priority value for an MISTP instance, the port with the lowest port number
forwards frames for that instance.
Task
Command
Configure the MISTP port instance cost on
a port.
set spantree portinstancecost
{
mod/port
}
[
cost
cost
]
[
instances
]
