Руководство По Проектированию для Cisco Cisco Nexus 5010 Switch
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Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Po10 Root FWD 1000 128.4105 (vPC peer-link) Network P2p
Po51 Root FWD 200 128.4146 (vPC) P2p
Surprisingly, on the secondary peer, there are two root ports: the peer link (Po10 in this example) and the
PortChannel to the root (Po51 in this example).
When you use MST, remember that the region configuration for the primary and secondary vPC peers must match,
so you can also use config-sync for this configuration.
To verify that the configuration is correct from a vPC perspective, enter the following command:
nexus5000# show vpc consistency-parameters global
MST and vPC
Starting from Cisco NX-OS 5.0(3)N1(1a), a change to the region definition on one vPC peer causes vPC ports to
go down only on the vPC secondary device and not on both the vPC primary and secondary devices. This behavior
occurs because of the graceful consistency-check feature.
Note: As of Cisco NX-OS 5.0(3)N1(1a), graceful Type 1 consistency resolution does not apply to fabric extender
dual-homed mode. A change in the MST region may cause fabric extender ports to go down if the fabric extender
dual-homed mode. A change in the MST region may cause fabric extender ports to go down if the fabric extender
is dual-attached to the Cisco Nexus 5000 Series Switch.
In addition, you can configure the MST region as part of the config-sync and switch-profile specifications so that
the configuration is automatically synchronized between the vPC primary and secondary switches:
nexus5500-1(config)# config sync
nexus5500-1(config-sync)# switch-profile vpc-config
Switch-Profile started, Profile ID is 1
nexus5500-1(config-sync-sp)# spanning-tree mst configuration
nexus5500-1(config-sync-sp-mst)# name dc1
nexus5500-1(config-sync-sp-mst)# revision 3
nexus5500-1(config-sync-sp-mst)# instance 1 vlan 1-4093
nexus5500-1(config-sync-sp-mst)# exit
nexus5500-1(config-sync-sp)# commit
vPC Delay Restore Feature
After a vPC switch reloads and joins a vPC domain, it brings up the vPC ports. Sometimes, the vPC ports may
begin forwarding before the forwarding entries on the vPC switch are completely reprogrammed. As a result, traffic
may flow from servers or downstream switches toward this vPC switch, where this traffic would then be dropped.
To address this scenario, vPC offers the option to delay the restoration of the vPC ports for a configurable time.
This time is 30 seconds by default. The configuration command is called delay restore.
The delay restore command uses two timers. The first timer to start is the interface VLAN timer. This timer by
default is set to 10 seconds regardless of whether the configuration uses SVIs. The second timer to start is the vPC
timer. This timer starts after the vPC peer link PortChannel has formed and switched into trunking mode (about 8
seconds after link up).