[c-nsp] Question about manually configuring 1000/Full on Cisco switches

[Christopher.Marget at usc-bt.com]

"speed 1000" on a copper port capable of 10/100/1000 disables 10 and 100 Mb/s operation by removing those modes from the list of those advertised to the link partner.

This may be useful if you would prefer a cable failure on pins 4, 5, 7 or 8 to drop the link and keep it down, rather than renegotiating it at 100 Mb/s.

N-way still runs.

/chris

> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> bounces at puck.nether.net] On Behalf Of John Neiberger
> Sent: Sunday, October 31, 2010 8:08 PM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] Question about manually configuring 1000/Full on Cisco
> switches
> 
> I contend (with no proof whatsoever) that manually configuring 1000/Full on
> Cisco switches doesn't really do anything since autonegotiation is required by
> the 1000Base-T standard. I don't believe that manually configuring these
> settings actually disables autonegotiation. I know others who feel differently
> and still like to hard set each side of certain links, apparently thinking that
> connectivity issues they're seeing are the result of autonegotiation errors
> (which I disagree with for other reasons.)
> 
> Anyway, can you settle this? Let's take a Cisco 4948 as an example.
> Does manually configuring 1000/Full on an interface really do much? If so,
> what exactly does it do? Does it behave in a non-standard way by disabling
> autonegotiation?
> 
> Thanks,
> John
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