Weird VLAN Issue on Nexus 7Ks

[jonathanw84]

I am seeing a weird issue on a new VLAN. Pings to resources on this new VLAN fluctuate and are inconsistent and often times drop packets.

We have two Nexus 7Ks, and the particular VDC in question is VPCd. The new VLAN is set up like any other - an SVI on each 7K and HSRP with 7K-1 having  higher priority than 7K-2. However, when I shut down the SVI for this VLAN on 7K-2, the issue goes away and pings to resources on this particular network are normal.

No indication of an HSRP or VPC issue. We have hundreds of other VLANs that are set up in a similar fashion with no issue. Any ideas?

[MHM Cisco World]

How hsrp have different priority? 

This nexus vpc so both must same,

Traffic will send to primary and that ok 

Traffic also send to secondary " becuase of vpc" secondary will reforward it to primary and i thing it drop there.

Check if both mac address of hsrp for this vlan mark with G.

Are you config any peer-gateway?

[Georg Pauwen]

Hello,

which is the root switch for that particular Vlan ? Is that the same as for the 'working' Vlans ?

[jonathanw84]

Thanks for the responses everyone! It turns we had actually hit a bug with the version we are on. Essentially on one of our cores, routes from the routing table were not getting pushed down to the CEF table, and traffic hitting that one core was dropping (hence why the issue went away when I shut down the problematic core). TAC recommended us to reboot both cores to fix the issue and that cleared it up...for now...