[c-nsp] 1Gig->10Gig port-channel migration

[Phil Mayers]

On 13/10/11 16:51, Tim Durack wrote:
> On Thu, Oct 13, 2011 at 11:24 AM, Phil Mayers<p.mayers at imperial.ac.uk>  wrote:
>> On 13/10/11 16:03, Tim Durack wrote:
>>
>>>
>>> I had hoped I could add the 10Gig links to the existing port-channel,
>>> and remove the 1Gig links.
>>
>> No can do, as you've doubtless discovered.
>
> Yes, thanks for confirming ;-(
>
>>> Next best idea is to migrate the 1Gig port-channel to Po2, and create
>>> a new Po1 with 10Gig links (I would like to maintain Po1 as the pop
>>> backbone.)
>>
>> I would just do this, then let STP choose the higher bandwidth link.
>>
>
> Any idea what the STP impact is likely to be? Sub-second? 30s? Wild
> STP oscillations that eventually recover 3 days later after disabling
> all redundant links? (Our STP is stable, but I still have a healthy
> fear of "waking the sleeping giant.")

No idea I'm afraid; I haven't timed STP in those circumstances.

In principle it should be fast; although I'm not sure how quickly the 
FDB will re-learn once the 10gig channel takes over.