Nexus 7K Peer Keepalive link

[tyagi.v]

Hi,

As per best practice how many physical link shall we use for vPC peer keepalive link ?

In many document its wriiten to use managment interface only , but a single interface is suffecient for this or we should have atleast 2 interfaces ?

Vijay

[Reza Sharifi]

Hi,

Single interface (mgmt0) is sufficient.  There is not much traffic going over this interface.  It is mostly keep alive messages between the 7Ks.

HTH

[tyagi.v]

Thanks , but if keepalive will goes down then what will happen ?

Also is it recommended to connect managment interfaces back to back with a cross cable or we need to place a switch in between ?

[Reza Sharifi]

It is recommended to use a switch

see figure-3 in this link:

http://www.cisco.com/en/US/prod/collateral/switches/ps9441/ps9670/configuration_guide_c07-543563.html

[manten808]

I believe best practice is to have them homed to different switch, and use seperate vrf just for the keep-alive. We use that topology with our 7ks

http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/operations/n5k_vpc_ops.html#wp425287

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.