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Config Example LAG between C3 stack and summit X450-g2 MLAG

Config Example LAG between C3 stack and summit X450-g2 MLAG

New Contributor
Hello All

Does anyone have a good and stable config example for me to set up a lag of 4Gb (4x1Gb) between a C3 stack of 4 units and a MLag setup of 2 Summit X450-G2 switches?

The Mlag peering config of the X450-G2 is al ready running and stable, but I'm struggling with setting up a stable LAG with the C3 stack.

tkx Rien


When using MLAG to a SecureStack you need to disable STP on the ports connected Set spa breed portadmin ( ports of the lag)

New Contributor II

do you have rstp or stp enabled on C3 Stack?

If yes you need to take out the LAG ports from rstp/stp.


Since Extreme's MLAG does not interact with STP, that recommendation is sensible. The two MLAG peers use different bridge IDs when generating BPDUs.
The default settings on e.g. a Cisco IOS switch put a port-channel into err-disabled mode on receiving BPDUs with differing bridge IDs on different member ports of a port-channel. But this is only relevant if STP is enabled on the EXOS switches.

With only the C3 sending BPDUs out the LAG and the X450-G2 ignoring them, spanning tree on the C3 handles the LAG as an edge port.

Some weeks ago I had a similar porblem and Extreme recommend not to have stp/rstp configured to the ports were MGLA/LAG is configured.