11-27-2012 10:09 AM - edited 03-07-2019 10:16 AM
scenario:
3750a, 3750b, and 3750c are connected via stackwise. these switches are then connected to g0/1-3 of 3560G via port-channel.
3750a-g1/0/1-----g0/1-3560G
3750b-g2/0/1-----g0/2-3560G
3750c-g3/0/1-----g0/3-3560G
question:
1. what would be the outcome if one of the 3750 has been disconnected in the stack membership? for e.g. 3750b's stack-cable is remove.
2. if the root of all vlans is 3560G. what would be the result of stp topology in 3560G's perspective? since 3750b has been remove from the stack. I assume that the port-channel membership in 3750's perspective would be (g1/0/1 and g3/0/1)
Solved! Go to Solution.
11-27-2012 11:46 AM
but what about in 3560G's perspective, does g0/2 still be a part of the port-channel?
no, as soon as the physical link on the 3750 side go down, the same happens on 3560 side. So you loose that one link on both 3750 and 3560.
HTH
11-27-2012 10:18 AM
If the 3750s are stacked, they are logically one switch. So, if you loose one, nothing should happen since you have uplinks form other switches in the stack. And the Portchannel will have 2 links in it instead of 3.
HTH
11-27-2012 10:52 AM
FYI. i forgot to include this scenario.
***the connection of 3750b-g2/0/1-----g0/2-3560G is still active. only the stack cable of 3750b is remove.
11-27-2012 11:15 AM
since only the stack cable was removed. Yes Reza, 3750 will only have 2 active members in the port channel link. but what about in 3560G's perspective, does g0/2 still be a part of the port-channel?
If no, then I assume that 3750b-g2/0/1 is the DP and g0/2-3560G is the RP?
If yes, is this some sort of violation in port-channel? what will be the effect on the users connected (if any) to 3750b?
11-27-2012 11:46 AM
but what about in 3560G's perspective, does g0/2 still be a part of the port-channel?
no, as soon as the physical link on the 3750 side go down, the same happens on 3560 side. So you loose that one link on both 3750 and 3560.
HTH
11-27-2012 06:48 PM
great thanks.
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