Руководство По Проектированию для Cisco Cisco Nexus 5010 Switch
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Spanning Tree and vPC
The behavior of spanning tree with vPC is slightly different than without vPC because vPC peers must provide the
illusion of a single spanning-tree node on the vPC-connected neighbors.
The output of show commands sometimes may surprise you because the vPC peer link is always forwarding, and
only the primary vPC peer processes BPDUs.
For example, if nexus5k01 is the vPC primary switch, nexus5k02 is the vPC secondary switch, and Po10 is the
peer link, if Po51 is the double-sided vPC connecting to the Cisco Nexus 7000 Series Switch, you will get this
result:
tc-nexus5k01# show spanning-tree vlan 50
MST0001
Spanning tree enabled protocol mstp
Root ID Priority 24577
Address 001b.54c2.80c2
Cost 1200
Port 4146 (port-channel51)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 000d.eca3.477c
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Po10 Desg FWD 1000 128.4105 (vPC peer-link) Network P2p
Po51 Root FWD 200 128.4146 (vPC) P2p
tc-nexus5k02# show spanning-tree vlan 50
MST0001
Spanning tree enabled protocol mstp
Root ID Priority 24577
Address 001b.54c2.80c2
Cost 2200
Port 4105 (port-channel10)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 000d.eca3.47fc
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec