Change link from 1Gx2 to 10G with no downtime

[heath]

I have a L3 link between two core switches that is two 1G links in an etherchannel.  I want to change that to a single 10G link, but not have any downtime.  My plan was to just swap out the SFPs on one of the links, leaving the other link up during the process.  Then I could take down the second link.  However, when I swapped out the SFPs, that link changed state to "suspended" on both switches.  This log message was generated:

Code Select Expand

Te1/1 is not compatible with Te1/2 and will be suspended (speed of Te1/1 is 10G, Te1/2 is 1000M)

Is there a way to swap that, force Te1/2 to be the suspended link and Te1/1 to be the active link without any noticeable downtime?  If I shutdown the Te1/2 port, will Te1/1 be unsuspended, or would I need to shut/no shut it as well?  If the latter, would that have be done on both switches?

I tried mocking this up with Cisco Packet Tracer, using a 100M and 1G port, but it was happy to let them both be in an etherchannel together.  I could not replicate the "suspended" state, even when I forced the 10/100 link to 10M.

[Otanx]

If it is L3 you can just put some different IP space on it. Bring it up side by side, and then update routing to use the new link. That is how I would handle it.

-Otanx

[config t]

Yeah link aggregation in practice needs similar links from what I've seen. There could be differences between PAgP and LACP but my gut tells me all the links have to be the same type.

If it is L3 you can just put some different IP space on it. Bring it up side by side, and then update routing to use the new link. That is how I would handle it.

-Otanx

Took the words right outta my mouth.

[heath]

I thought about that a while after posting my question and now feel stupid that I didn't immediately think about it!  I was just too focused on that one idea.

[deanwebb]

I like firewalls.

[Dieselboy]

It's probably a layer 2 link. You cannot have etherchannel with links of different speeds. Are you using spanning tree there? You could;
1. disconnect one of the links
2. upgrade the sfps for the new link
3. configure the now not connected link into a new and separate etherchannel group
4. plug in the new link
5. check spanning tree which is forwarding and adjust costs if necessary to make the new link the active link forwarding traffic (this should then block the lower bandwidth link)
6. now you can remove the lower bandwidth link