MEC with VSS (WS-C6832) and Stacking (WS-C2960X)

[ts-stg]

During Planning a complex LAN refresh one question arrived about the behavior of splitted Ethernetchannels build in error. 

For example swapped two Ethernet Links, upper Tabelle as designed and configured,  lower table physical implemented

What kind of error Messages / States are expected in such state on Distribution Switch Port channel Interfaces 

[vb10 · Accepted solution]

Hello,

So, as I understood, situation is described, when we have port-channel on Distribution switch, which goes to 2 different access switches.

In this case behavior and error messages depends on configuration.  If dynamic aggregation protocol is used (PAGP or LACP), then it should be detected by distribution switch, that on other side there are 2 different IDs on other side of the port-channel, and one or both links should be suspended in Port-channel with error something like "Port-channel misconfig" or similar.

If static aggregation is used (mode on), then situation might be worse. Though, it also should be detected by STP protocol, if STP is enabled, when distribution switch will receive BPDUs on port-channel members from different neighbors. But it might take more time. And after that physical port should be err-disabled with message something like STP Channel-misconfig.