Recommended setup 3120 stack to VSS

[mo shea]

Hi...

We have a new setup of 2 6509 core switches running VSS and 4 3120 Cisco Blade switches cross stacked. I have run MEC between the VSS cores and the 3120 stack using etherchannel ON mode, bundling 4 sfps, 1 on each 3120. I have the following queries.

- Is using ON mode recmmended for this setup.

- Is pagp not supported for 3120 stacks

- What is the recommended setup for dual active for this setup.

Thanks in advance

[Reza Sharifi]

Mo,

For cross stacked etherchannel only LACP is supported. PAGP is supported only if you are connecting all you downlinks from the 6500s to the same 3120

We use 3110X (10Gig) to uplink our IBM chassis to our VSS switches. using LACP.

HTH

Reza

[mo shea]

Thanks for your response.

Is there a benefit if we switch from unconditional ON mode to lacp.

Can you point me to a document where it shows that pagp is not supported

Thanks again

[Reza Sharifi]

LACP will help you if there is peer-link miss-configuration and also a better failover handling.

We tested LACP failover by disconnecting physical fiber links from the chassis or the 6500 VSS and it worked really well. We did not even miss a ping when we pulled cables.

Thanks,

Reza