Nexus 7000 4.2(6) vpc failure scenario

[sumitmahla]

Hello All,

I was going through NX-OS 4.2 document's, and i have a question regarding what will happen if :

There  are two nexus 7k with single SUP and vpc configured and conncted to  Fabric interconnect. Like each Fabric interconnect is connected to both  Nexus 7k on the VPC configured member ports of Nexus 7k.

What if one of the cases given below occurs :

1. Secondary VPC Peer is rebooted

2. Secondary VPC is powered down by power cut and then brought back up

3. If Peer-link and Peer-keepalive ports goes down but other ports and sup and chassis is working fine.

Please provide valueable suggestion for the three scenarios

[jkilleda]

Hi Sumit,

Nexus 7000 4.2(6) vpc failure scenario
In VPC senario , if the secondary VPC peer switch is goes down , there will be no impact on the network ; traffic will still flow through primary switch

[Rick1776]

1. Secondary VPC Peer is rebooted
If your FAbric Intercinnects are dual homed traffic will still continue to flow through the primary.
2. Secondary VPC is powered down by power cut and then brought back up
Once the Secondary comes back online the traffic will start to normalize and flow from both switches
3. If Peer-link and Peer-keepalive ports goes down but other ports and sup and chassis is working fine.
This is typical situation, if both the peer-link and peer-keepalive go down then each switch will act independently you could get into a situation with Asyncronous routing.

If you look at vpc best practice you can look at enabling the following:
Peer-Switch
Peer-Gateway (depending on design)
VPC Auto-Recovery

These are the three most common
This is a great link with all the best practices.
https://www.cisco.com/c/dam/en/us/td/docs/switches/datacenter/sw/design/vpc_design/vpc_best_practices_design_guide.pdf