Cisco Cisco Nexus 5010 Switch Guida Alla Progettazione

Design Guide

Page 36 of 38

agg1(config-if)# channel-group 51 mode active

agg1(config)#interface Port-channel 51

agg1(config-if)# switchport

agg1(config-if)# vpc 51

agg2(config)#interface ethernet2/9

agg2(config-if)# channel-group 51 mode active

agg2(config)#interface Port-channel 51

agg2(config-if)#switchport

agg2(config-if)# vpc 51

If the consistency check does not show success, you should verify the consistency parameters. Typical reasons that

a vPC may not form include the following:

●

The VLAN that is defined in the trunk does not exist, or it is not defined on the peer link

●

One member port is configured as the access and the other as the trunk

●

Mismatches exist in the VLANs that are carried on the trunk, etc

The following example shows how to verify that the vPC configuration is consistent between two vPC peers for the

global consistency parameter as well as for a specific PortChannel:

tc-nexus7k01-vdc2# show vpc consistency-parameters global

tc-nexus7k01-vdc2# show vpc consistency-parameters int port-channel 51

Legend:

Type 1 : vPC will be suspended in case of mismatch

Name Type Local Value Peer Value

------------- ---- ---------------------- -----------------------

STP Port Type 1 Default Default

STP Port Guard 1 None None

STP MST Simulate PVST 1 Default Default

Allowed vLANs - 10-14,21-24,50,60 10-14,21-24,50,60

After a port is defined as part of a PortChannel, any additional configurations, such as activation or disablement of

Bridge Assurance or trunking mode, are performed in the interface PortChannel configuration mode. Trying to

configure spanning-tree properties for the physical interface instead of the PortChannel will result in an error

message.

LACP

You should use LACP for dynamic bundling of the ports in the vPC group, because LACP verifies that the ports being

bundled are actually part of the same physical or virtual switch, preventing erroneous configurations.

For example, if the PortChannel is configured as active on the Cisco Nexus 7000 Series Switch and the downstream

switch is not configured for PortChannel, the PortChannel ports will be shown as in the individual (I) state and will run

regular spanning tree.

After the access layer switches are configured for LACP, the negotiation completes the PortChannel forms:

tc-nexus5k01(config)# int eth2/1-2

tc-nexus5k01(config-if-range)# channel-group 51 mode passive