Guidelines And Limitations For Vpcs; Verifying The Vpc Configuration - Cisco Nexus 3548 Configuration Manual

Configuring Virtual Port Channels
Note Peer-switch is supported on networks that use vPC, and STP-based redundancy is not supported. If the vPC
peer-link fails in a hybrid peer-switch configuration, you can lose traffic. In this scenario, the vPC peers use
the same STP root ID as well as the same bridge ID. The access switch traffic is split in two with half going
to the first vPC peer and the other half to the second vPC peer. With peer link failure, there is no impact to
the north/south traffic but the east/west traffic is lost.

Guidelines and Limitations for vPCs

vPCs have the following configuration guidelines and limitations:
• vPC is not qualified with IPv6.
• VPC is now supported in Warp mode on the Cisco Nexus 3500 Series platform.
• You must enable the vPC feature before you can configure vPC peer-link and vPC interfaces.
• You must configure the peer-keepalive link before the system can form the vPC peer link.
• The vPC peer-link needs to be formed using a minimum of two 10-Gigabit Ethernet interfaces.
• We recommend that you configure the same vPC domain ID on both peers and the domain ID should be
• Only port channels can be in vPCs. A vPC can be configured on a normal port channel (switch-to-switch
• You must configure both vPC peer switches; the configuration is not automatically synchronized between
• Check that the necessary configuration parameters are compatible on both sides of the vPC peer link.
• You might experience minimal traffic disruption while configuring vPCs.
• You should configure all port channels in the vPC using LACP with the interfaces in active mode.
• You might experience traffic disruption when the first member of a vPC is brought up.
• SVI limitation: When a BFD session is over SVI using virtual port-channel(vPC) peer-link, the BFD

Verifying the vPC Configuration

Use the following commands to display vPC configuration information:
Command
switch# show feature
unique in the network. For example, if there are two different vPCs (one in access and one in aggregation)
then each vPC should have a unique domain ID.
vPC topology) and on a port channel host interface (host interface vPC topology).
the vPC peer devices.
echo function is not supported. You must disable the BFD echo function for all sessions over SVI between
vPC peer nodes using no bfd echo at the SVI configuration level.
Cisco Nexus 3548 Switch NX-OS Interfaces Configuration Guide, Release 9x
Purpose
Displays whether vPC is enabled or not.
Guidelines and Limitations for vPCs
67