Cisco WS-C4003 Software Guide - Page 120
Configuring MISTP Port Instance Cost
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Using MISTP-PVST+ or MISTP Chapter 7 Configuring Spanning Tree 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 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 Instance Cost You can configure 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 to 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. Command set spantree portinstancecost {mod/port} [cost cost] [instances] This example shows how to configure the port instance priority 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 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 to 63. If all ports have the same priority value for a MISTP instance, the port with the lowest port number forwards frames for that instance. 7-24 Software Configuration Guide-Catalyst 4000 Family, Catalyst 2948G, Catalyst 2980G, Releases 6.3 and 6.4 78-12647-02