Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.


Nexus 7k VPC connecting to Juniper MX series?


I'm in a situation where I need to link my Nexus 7k core (two 7010's running multiple VPC's) to a pair of Juniper MX-240 switch/routers.

Both devices are capable of a form of VPC - Juniper call it MC-LAG (Multi-chassis Link Aggregation), Cisco obviously call it VPC.

What I need to find out is if a VPC across the two-Nexus system will be compatible with a MC-LAG on the Juniper setup. I have VPC's working find to other Cisco devices.

As far as I can tell from the reading fo the standards I can find it *should* work, but since I'm working in production I'm very wary of making a change which would cause an issue in this.

Has anyone done this/come across this before? Anyone got any insight if it's possible?


Everyone's tags (2)

Re: Nexus 7k VPC connecting to Juniper MX series?

Answering my own question for reference of anyone else who might need to know.

It *is* possible, but you only get an active/active LACP connection to an EX series switch running in a virtual chassis configuration.

Juniper's implementation of MC-LAG on non-EX devices only supports active/standby mode - one port of the VPC on the Nexus pair will go immediately into hot-standby mode and stay that way.

You have to fiddle with the LACP priorities to get any form of failover working - otherwiswe, the only way I could find to get the second leg of the LACP to go active was to shut down the primary on the Nexus, then shut down and no shut the port on the second Nexus.

To an EX series switch, LACP "just worked".