Hey,
to make a long story short - we had some back and for with Avaya and it all boils down to a small hint that can be found in NN48500-502:
When there is multiple links active in a LAG and you fall back to just a single link, a LAG
is no longer formed and by default you are left with just a single link. If Spanning Tree,
i.e. STP or RSTP, is implement, typically you will see a re-convergence in such a
situation with standards based 802.3ad implementations.
With the ES470, ERS5500
and on the ERS4500 (v5.1.1 for the ERS4500), the switch will operate in a slightly
different way. That is, once a port is a member of a LAG, it will always remain a LAG
member even if there is just a single link active in the LAG. This has the benefit of
improving resiliency when interoperating in situations where Spanning Tree is being
used.
So this works as designed
So to say, LACP (on the ES470) is only useful if you are in a Nortel only network where you probably
prefer to run MLT with VLACP.
Cheers
Philipp
