I have a network infrastructure that has VERY low tolerance / requirement for packet loss. We have implemented nexus 5672UP (running version 7.3(5)N1(1)) in a single sided VPC configuration with 15 vpc member switches with port channels back up to the VPC peers. All fiber paths are redundant between the VPC peers and out to the VPC members. Very simple layer 2 only configuration. No layer 3 routing for the closed network. We do have critical multicast traffic in this environment. Again all layer 2 so just relying on the VPC Peer switches acting as the IGMP querier for the VLAN.
What makes this deployment very interesting is the extreme packet loss requirements during failure scenarios. I can't have more than 500ms of packet loss during any of the following network failures:
1) loss of a single link to vpc member switch,
2) loss of both keep-alive links (Po1),
3) loss of both vpc-peer-links (Po2),
4) loss of the Primary Operational VPC Peer
5) loss of the Primary Secondary VPC Peer
Should I anticipate being able to meet these requirements? I am currently not, yet I have followed all the best practices for the configurations.
Regarding failure scenario 1, I am experiencing brief packet loss 600ms when I disconnect a link in one of my vpc member port channels. I would have expected to not lose any packets as I have two uplinks in port-channel configuration and loosing one of the links should not cause any reconvergence in the solution, at least not for the port-channel or spanning-tree. Is VPC reconvergence operations causing the dropping of the packets? is that normal?
Regarding VPC-peer link (failure scenario 3)... no packet loss. Good.
Regarding VPC peer switch failures (failure scenario 4/5)... we are getting couple seconds of packet loss when the switch comes back on line, not when the switch goes down. Any ideas on this? How can we prevent?
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