CrossStack Etherchannel Setup

[Dragonss]

Hello Guys, we are implementing cross Stack ether channel but has some queries before implementing it. Refer attached diagrams

planning will be to connect cable from 9200 switch to Stack1 & Stack 3 member & from 3850 switch connect cable to Member1 & member 2. Catalyst switches mentioned are individual switches. Can we perform crossstack in this manner and are there any chances of looping if any stack member fails.

Guys let me know what could be the best way to achieve it

[MHM Cisco World]

Only make cross connection port channel and there is no loop.

I.e. the cat9 will have one port channel to two stack SW.

[Dragonss]

yes it worked and there is no loops observed in switches

[MHM Cisco World]

You are so welcome.

MHM

[ammahend]

its not uncommon, if you think of the stack as single switch, its really a point to point connection, so no loop.

[Joseph W. Doherty]

Yes, you should be able to do that.

No loop if using Etherchannel.

Why two connections to #1?

BTW, Cisco, for some of their stackable switches, recommend stack master not host uplinks.

[Dragonss]

hello , yes loop didn't occurred. Can you tell why uplink to master is not recommended.

[Joseph W. Doherty]

"Can you tell why uplink to master is not recommended."

I believe the Cisco's recommendation is based on avoiding any additional load on the stack's master, as that switch is "extra" busy supporting the control plane for the whole stack.

In my experience, in routine/typical operations, I haven't seen a master being overwhelmed by hosting busier (?) ports.  But, Cisco recommendations tend to be very conservative and seem to be oriented toward avoiding possible performance issues.

[Dragonss]

yes , i checked properly existing up-link was going to Stack 2 and not stack 1.