SMLT over LACP not coming up with when configuring with any of the third part device like Cisco, NetApp, HP.
SMLT remains in norm state.
SW : All release
There could be many cause of this behaviour.
While configuring LACP we need to take special care of the situation where LACP misconfiguration may cause loop over the link and STP puts one of link in discarding state.
On ERS side make sure that we have the correct configuration(LACPkeys on ethernet interface and MLT) and wokring links(No FCS or other errors).
Even if you make sure to use the correct configuration, sometimes in LACP or any aggregation we face the situation where one side get aggregated and other side delays in aggregation due to some reason. This also causes the loop and puts down the redundant links. We must ensure the STP status of the links in case LACP not comming up.
Below is the configuration issue found with one of the customer:
Duplicate LACP key for two separte LAGs.
ethernet 2/19 lacp key 13
ethernet 2/26 lacp key 13
ethernet 2/28 lacp key 13
After changing the LACP key of seprate LAGs, this started to work.