Cisco Nexus VPC Domain ID
For the last 3 days, I’ve tried to configure vPC for a pair of Nexus 5548UP. No matter what I did, the pair just refused to connect and form vPC properly. So far I have tried:
- Upgrading to NX-OS version 6
- Upgrading to NX-OS version 7
- Restarting to factory default configs
- Restarting the switches many times
- Checking cables and connectors
The configurations I had for them were
Shared Config:
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vlan 62 name TEST interface Ethernet1/1 switchport access vlan 62 speed 1000 channel-group 101 mode active interface Ethernet1/2 switchport access vlan 62 speed 1000 channel-group 101 mode active interface Ethernet1/3 switchport mode trunk channel-group 102 mode active interface Ethernet1/4 switchport mode trunk channel-group 102 mode active interface port-channel101 description vPC-KeepAlive switchport access vlan 62 spanning-tree port type network speed 1000 interface port-channel102 description PeerLink switchport mode trunk spanning-tree port type network speed 10000 vpc peer-link |
First switch
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interface Vlan1 no shutdown ip address 172.16.0.x1/24 interface Vlan62 no shutdown ip address 1.1.1.1/30 vpc domain 101 peer-switch role priority 5000 peer-keepalive destination 1.1.1.2 source 1.1.1.1 vrf default auto-recovery |
Second switch
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interface Vlan1 no shutdown ip address 172.16.0.x2/24 interface Vlan62 no shutdown ip address 1.1.1.2/30 vpc domain 101 peer-switch role priority 1 peer-keepalive destination 1.1.1.1 source 1.1.1.2 vrf default auto-recovery |
And I kept getting this
Therefore,
Do you see the problem? It turned out that’s because I used the same vPC Domain ID as my KeepAlive Port-Channel ID :101. A mistake that can be made easily in my effort of keeping the code clean.
I fixed it by changing everything I could about the configuration, eventually I changed the vPC domain ID and it works
Then I found this Cisco document:
vPC Domain ID Modification on an Active vPC Domain
The vPC peer devices use the vPC domain ID that you configure in order to automatically assign a unique vPC system MAC address. Each vPC domain has a unique MAC address that is used as a unique identifier for the specific vPC-related operations. However, the devices use the vPC system MAC addresses only for link-scope operations, such as LACP. Therefore, Cisco recommends that you create each vPC domain within the contiguous Layer 2 network with a unique domain ID.