This is my network topology where I have SW-1 is configured for
HSRP for multiple VLANs,
SW-3 connected to SW-1 using vPC. Last few month I am dealing with this unicast flooding where whenever I add a new switch in network or spanning-tree changed I noticed for 5 second or so all my switch ports seeing entire network traffic like traffic get mirror on every single switch in datacenter.
After collecting lots of data I found this flooding only happens in one side of network which is
SW-3 so whatever TOR switch connected to SW-3 seeing unicast flooding, after comparing configuration I found only one parameter is missing in
SW-3 which is
peer-gateway. I have no idea that is the issue but i want to see what you guys suggesting, I thought peer-gateway is only for HSRP switch not for L2 switch.
Here is the config for vPC
SW-1 (ROOT bridge)
vpc domain 1 peer-switch role priority 10 peer-keepalive destination 172.29.0.7 source 172.29.0.6 peer-gateway auto-recovery ip arp synchronize
vpc domain 2 peer-switch role priority 10 peer-keepalive destination 172.29.0.103 source 172.29.0.102 peer-gateway auto-recovery ip arp synchronize
SW-3 ( missing peer-gateway here)
vpc domain 3 peer-switch role priority 10 peer-keepalive destination 172.29.0.161 source 172.29.0.162 auto-recovery ip arp synchronize
Should I need to configure peer-gateway on SW-3 or its totally not related and I should keep digging somewhere else?
I have earlier posted question here which I may delete it if this question get resolved: Strange flooding during installing new switch in network