Cisco Nexus 5000 Series - Vpc Peer Keepalive Link Failure

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Cisco Nexus 5000 Series NX-OS Interfaces Operations Guide, Release 5.0(3)N2(1)
Chapter 1 Virtual Port Channel Operations
vPC Failure Recovery
Figure 1-2 vPC Response to a Peer Link Failure
A vPC consistency check cannot be done when a vPC peer-link is down either due to a link failure or
when the peer switch is completely down. In either case, any newly configured vPC does not come up
because the vPC consistency check cannot proceed, or the existing vPC remains disabled after the link
flaps.
Use the reload restore feature that was introduced in Cisco NX-OS Release 5.0(2)N1(1) to fix this
problem. The reload restore feature allows a switch to bypass the vPC consistency check and bring up
vPC ports when the peer-link or peer switch fails. The reload restore feature has been replaced with the
auto-recovery feature in Cisco NX-OS Release 5.0(2)N2(1).
vPC Peer Keepalive Link Failure
The vPC keepalive link carries the heartbeat message between two vPC peer switches. The failure of the
vPC keepalive link alone does not impact the vPC operation or data forwarding. Although it has no
impact on data forwarding, we recommend that you fix the keepalive as soon as possible to avoid a
double failure scenario that could impact the data traffic.
When both switches come up together (such as after power gets restored following a power outage) and
only the mgmt/keepalive link fails, the peers are unreachable. However, all other links, including vPC
peer links, are up. In this scenario, reaching the vpc-peers through keepalives are achieved through
keepalive links while the primary and secondary role election is established through the vpc-peer link.
You must establish the first keepalive for the role election to occur in the case when a switch comes up
and the vPC-peer link is up.
When keepalives fail to reach the peer switches, role election does not proceed and the primary or
secondary role is not established on either vPC peer switch and all vPC interfaces are kept down on both
switches.
MAC_C
SW
MAC_A
vPC
Primary
vPC
Secondary
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vPC member
port is suspended
vPC member
port is suspended