Cisco WS-C2948G-GE-TX Configuration Manual page 133

Chapter 7 Configuring Spanning Tree
Port
------------------------ ---- ------------- --------- ---- -------- ----------
1/1
3/1
3/25
3/26
3/27
3/28
3/29
3/30
7/1-4
7/5
7/6
8/37
8/38
15/1
16/1
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
that are attached to faster media (such as full duplex) and higher numbers to ports that are attached to
slower media. The default cost differs for different media. The possible value for port instance cost is
from 1–268435456.
To configure the port instance cost for a port, perform this task in privileged mode:
Task
Configure the port instance cost on a
switch port.
This example shows how to configure the MISTP port instance cost on a port:
Console> (enable) set spantree portinstancecost 1/1 cost 110110 2
Port 1/1 instances 1,3-16 have path cost 20000.
Port 1/1 instances 2 have path cost 110110.
This parameter applies to trunking ports only.
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 from
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.
To configure the port instance priority on an MISTP instance, perform this task in privileged mode:
Task
Configure the port instance priority on an MISTP
instance.
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Software Configuration Guide—Release 8.2GLX
78-15908-01
Inst Port-State Cost
1 forwarding
1 forwarding 200000
1 forwarding 200000
1 forwarding 200000
1 forwarding 200000
1 forwarding 200000
1 forwarding 200000
1 forwarding 200000
1 blocking
1 forwarding
1 forwarding
1 blocking 200000
1 blocking 200000
1 forwarding
1 forwarding
Command
set spantree portinstancecost {mod/port} [cost cost]
[instances]
Command
set spantree portinstancepri {mod/port}
priority [instances]
Using MISTP-PVST+ or MISTP
Prio Portfast Channel_id
20000 32 disabled 0
32 disabled 0
32 disabled 0
32 disabled 0
32 disabled 0
32 disabled 0
32 disabled 0
32 disabled 0
5000 32 disabled 833
20000 32 disabled 0
20000 32 disabled 0
32 disabled 0
32 disabled 0
20000 32 enabled 0
20000 32 enabled 0
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