Last Updated on August 2, 2021 by Admin 2
You issue the following commands on SwitchA and SwitchB, which are Cisco Nexus 7000 Series switches
SwitchA(config)#vpc domain 101 SwitchA(config-vpc-domain)#peer-keepalive destination 192.168.1.2 source 192.168.1.1 vrf default SwitchA(config-vpc-domain)#exit SwitchA(config)#interface range ethernet 2/1 - 2 SwitchA(config-if-range)#switchport SwitchA(config-if-range)#channel-group 1 mode active SwitchA(config-if-range)#interface port-channel 1 SwitchA(config-if)#switchport mode trunk SwitchB(config)#vpc domain 101 SwitchB(config-vpc-domain)#peer-keepalive destination 192.168.1.1 source 192.168.1.2 vrf default SwitchB(config-vpc-domain)#exit SwitchB(config)#interface range ethernet 2/1 - 2 SwitchB(config-if-range)#switchport SwitchB(config-if-range)#channel-group 1 mode active SwitchB(config-if-range)#interface port-channel 1 SwitchB(config-if)#switchport mode access
Which of the following is most likely a problem with this configuration?
- The Ethernet port range is using the wrong channel group mode on SwitchB.
- The vpc peer-link command is missing from SwitchA.
- The vpc peer-link command must be issued on both switches.
- Port-channel 1 on both switches should be an access port.
- The vPC domain ID on SwitchB should be a different value.
Most likely, the vpc peer-link command must be issued on both switches to complete the configuration in this scenario. A virtual port channel (vPC) peer link should always be comprised of 10-gigabit-per-second (Gbps) Ethernet ports. Peer links are configured as a port channel between the two members of the vPC domain. You should configure vPC peer links after you have successfully configured a peer keepalive link. Cisco recommends connecting two 10-Gbps Ethernet ports from two different input/output (I/O) modules. To configure a peer link, you should issue the vpc peer-link command in interface configuration mode. For example, the following commands configure a peer link on Port-channel 1:
SwitchA(config)#interface port-channel 1 SwitchA(config-if)#switchport mode trunk SwitchA(config-if)#vpc peer-link SwitchB(config)#interface port-channel 1 SwitchB(config-if)#switchport mode trunk SwitchB(config-if)#vpc peer-link
Port-channel 1 on both switches should be a trunk port. Trunk ports are used to carry traffic from multiple virtual local area networks (VLANs) across physical switches. Access ports can only carry data from a single VLAN and are typically connected to end devices, such as hosts or servers.
It is not a problem that the channel group mode is configured to active on the Ethernet ports in this scenario. It is important to issue the correct channel-group commands on a port channel’s member ports prior to configuring the port channel. For example, if you are creating Port-channel 1 by using the Ethernet 2/1 and Ethernet 2/2 interfaces, you could issue the following commands on each switch to correctly configure those interfaces as members of the port channel:
SwitchA(config)#interface range ethernet 2/1 - 2 SwitchA(config-if-range)#switchport SwitchA(config-if-range)#channel-group 1 mode active SwitchB(config)#interface range ethernet 2/1 - 2 SwitchB(config-if-range)#switchport SwitchB(config-if-range)#channel-group 1 mode active
The vPC domain ID on SwitchB should be the same value as the vPC domain ID on SwitchA. A vPC domain is comprised of two switches per domain. Each switch in the vPC domain must be configured with the same vPC domain ID. To enable vPC configuration on a Cisco Nexus 7000 Series switch, you should issue the feature vpc command on both switches. To assign the vPC domain ID, you should issue the vpc domain domain-id command, where domain-id is an integer in the range from 1 through 1000, in global configuration mode. For example, issuing the vpc domain 101 command on a Cisco Nexus 7000 Series switch configures the switch with a vPC domain ID of 101.