VSP7000 IST & VLACP

[Marc_Daley]

According to varying design docs / best practice it is recommended to disable VLACP on IST links of a VSP7000 cluster. However, I cannot find anywhere that says why. Anyone know?

[Marc_Daley]

That's great, thanks for the detailed response. In the case of running traditional IST with SMLT I assume only b) in your answer applies? A colleague also mentioned that there may be some ASIC restriction with the 7ks?

[Roger_Lapuh]

There are a couple reasons:a) VLACP is a link based protocol, vIST can use any NNI link that is up, so VLACP does not really make sense.b) we only want the vIST session to go down when the peer switch is really down, thus we have pretty long timers, in case there are some intermittent failures, VLACP would interfere with those timers. When vIST session goes down, then vIST nodes convert their SMLT ports to normal ports, thus intermittent IST link down events would increase the risk for loops.I hope this helps, Roger