Cisco WS-C4003 Software Guide - Page 119

Configuring MISTP Port Cost, mod_num/port_num, instance, priority

Page 119 highlights

Chapter 7 Configuring Spanning Tree Using MISTP-PVST+ or MISTP Configuring MISTP Port Cost You can configure the port cost of switch ports. Ports with lower port costs are more likely to be chosen to forward frames. Assign lower numbers to ports attached to faster media (such as full duplex) and higher numbers to ports attached to slower media.The possible range is 1 to 65535. The default differs for different media. Path cost is typically equal to 1000 ÷ LAN speed in megabits per second. To configure the port cost for a port, perform this task in privileged mode: Step 1 Step 2 Task Configure the port cost for a switch port. Verify the port cost setting. Command set spantree portcost mod_num/port_num cost show spantree mistp-instance instance [mod_num/port_num] active This example shows how to configure the port instance priority on a MISTP instance and verify the configuration: Console> (enable) set spantree portcost 2/12 22222222 Spantree port 2/12 path cost set to 22222222. Console> (enable) show spantree mistp-instance active 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 Bridge ID Priority VLANs mapped: Bridge Max Age 20 sec 00-d0-00-4c-18-00 32769 (bridge priority: 32768, sys ID ext: 1) 6 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 MISTP Port Priority You can configure the port priority of switch ports. The port with the lowest priority value forwards frames for all VLANs. The possible port priority value is 0 to 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 port priority for a port, perform this task in privileged mode: Step 1 Step 2 Task Configure the port priority for a switch port. Verify the port priority setting. Command set spantree portpri mod_num/port_num priority [instance] show spantree mistp-instance instance [mod_num/port_num] active 78-12647-02 Software Configuration Guide-Catalyst 4000 Family, Catalyst 2948G, Catalyst 2980G, Releases 6.3 and 6.4 7-23

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7-23
Software Configuration Guide—Catalyst 4000 Family, Catalyst 2948G, Catalyst 2980G, Releases 6.3 and 6.4
78-12647-02
Chapter 7
Configuring Spanning Tree
Using MISTP-PVST+ or MISTP
Configuring MISTP Port Cost
You can configure the port cost of switch ports. Ports with lower port costs are more likely to be chosen
to forward frames. Assign lower numbers to ports attached to faster media (such as full duplex) and
higher numbers to ports attached to slower media.The possible range is 1 to 65535. The default differs
for different media. Path cost is typically equal to 1000 ÷ LAN speed in megabits per second.
To configure the port cost for a port, perform this task in privileged mode:
This example shows how to configure the port instance priority on a MISTP instance and verify the
configuration:
Console> (enable)
set spantree portcost 2/12 22222222
Spantree port 2/12 path cost set to 22222222.
Console> (enable)
show spantree mistp-instance active
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 MISTP Port Priority
You can configure the port priority of switch ports. The port with the lowest priority value forwards
frames for all VLANs. The possible port priority value is 0 to 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 port priority for a port, perform this task in privileged mode:
Task
Command
Step 1
Configure the port cost for a switch port.
set spantree portcost
mod_num/port_num
cost
Step 2
Verify the port cost setting.
show spantree
mistp-instance
instance
[
mod_num/port_num
]
active
Task
Command
Step 1
Configure the port priority for a switch port.
set spantree portpri
mod_num/port_num
priority
[
instance
]
Step 2
Verify the port priority setting.
show spantree
mistp-instance
instance
[
mod_num/port_num
]
active