[c-nsp] 500 msec timers on Cisco GLC-T

Marian Ďurkovič md at bts.sk
Wed May 6 03:32:13 EDT 2009

On Tue, 5 May 2009 20:16:11 -0400, Mike Louis wrote
> Hey Folks,
> One of my Cisco SEs told me the other day that there was a limitation 
> in the GLC-T GBICs that prevented the switch from recognizing a  link 
> up/down faster than 500 msec. This could cause a noticeable blip in a 
> voice call. Apparently this is not an issue in the fiber SFPs. Has 
> anyone ever heard of this  before. He was referencing a 3750 series 
> switch when we were discussing the issue. I am not sure if its 
> platform or GBIC specific. I also wonder if it affects normal 
> 10/100/1000 ports the same way. Any ideas or thoughts? Ever heard of 
> anything like this on other platforms?

This explains it in detail:



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