How LAG works in Cisco VSS

[Joel kurian]

1. I have done a LAG between Core and Aggregation switch

2. Configured VSS between the core switches

How do i make sure packet A and B takes the shortest path. should  i make any configuration change or will it work with the MAC table?

[Jon Marshall · Accepted solution]

They should take the shortest path by design.

VSS is designed so that each chassis always uses it's local links to forward traffic where possible eg. if you had a device that was attached to only one chassis and another device only attached to the other chassis then traffic would have to flow across the VSL between those devices which is why you should always attach any device to both chassis.

For specifics on traffic flow see this link -

http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Campus/VSS30dg/campusVSS_DG/VSS-dg_ch3.html#wp1079466

Jon