Upgrading L2 port channel from 2x1G to 2x10G SFP+

[pwwiddicombe]

I currently have a 2G L2 port channel PO1 between 2 core 4507E switches, which I now have the 10G SFP+ modules for.  All single-mode fiber.

What is the sequence of events that are likely to occur when this happens?  The links are currently using port 1 on each of Sup 8E supervisors in slots 3 and 4 on the switches.

My guess is the following, but there may be gotchas I am unaware of.

1.  Remove the link between the slot 3 Sups.  Connection is now running on Slot4 supervisors.  No outage yet.

2.  Insert the SFP+ modules and reconnect fiber.  At this point, I presume PO1A gets created, as there are mismatched speeds? 

3.  Disconnect the Slot 4 fiber link.  Now, will the bundle come up on the Slot 3 llinks automatically, and within seconds, or will the PO1 bundle require a reset because of the speed change?

4.  Put the SFP+ into slot 4 supervisors, and connect fiber.  Back to running a 2-link bundle.

[Reza Sharifi]

Regarding step 2:

I have never done this but the question is if all goes well, at the end you will be operating using po1A and if this PO does not have any config, wouldn't all traffic be blocked? So, one option maybe to copy all configs from PO1 to PO1A and hope that nothing else goes wrong during this process.

If you have 2 extra ports, the other option could be to put the SFP+s in 2 new ports, cable the ports, create a new Portchannel (2) and shut it down and add the config from po1 to po2.

In a short maintenance window shut down po1 and bring up po2.

If everything is ready ahead of time and test it, this window should not take more than 5 minutes.

HTH

[Leo Laohoo]

I agree with Reza. 

Step 2 will error-disable the EtherChannel due to mismatch speed.  

The easiest way is to organize a 5 minute outage window.  Otherwise, Po 1 will need to be broken up (after the SFP is removed) and then that interface will need to be reassigned to Po 2.  Going about this step is, potentially, more disruptive than a 5 minute outage.