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Re: Problems connectivity GE on Foundry BigIron to Cisco 2950T
From: Elijah Savage <esavage () digitalrage org>
Date: Sun, 15 Jan 2006 19:11:44 -0500
Sam Stickland wrote:
Replying to my own email..
I've found some sites that suggest it's not possible to disable
auto-negotiation on 1000Base-T since other operational parameters are
negotiated including selection of the master clock signal. I was aware
that flow control was negotiated, but not the clock signal.
Can anyone elaborate?
On Sun, 15 Jan 2006, Sam Stickland wrote:
On Sun, 15 Jan 2006, Paul G wrote:
----- Original Message ----- From: "Farrell,Bob" <bobf () studentsonly com>
To: "Randy Bush" <randy () psg com>; "David Hubbard"
<dhubbard () dino hostasaurus com>
Cc: "Sam Stickland" <sam_ml () spacething org>; <nanog () nanog org>
Sent: Sunday, January 15, 2006 4:45 PM
Subject: RE: Problems connectivity GE on Foundry BigIron to Cisco 2950T
the bigiron wants (iirc):
i strongly suggest you peruse the cli reference for both devices.
On the foundry GBIC blades you can't configure the speed and duplex
settings, they only support 1000-full.
Error - can't change speed and duplex mode
I've dug through as much information as I can about the cisco 2950T
and 802.3z/802.3ab and disabling the auto-negiation. There appears to
be no command at all available to do this.
The cabling arrangement is:
Foundry -- Straight -- Patch -- Underfloor -- Patch -- Crossover -- Cisco
GBIC Cable Panel Straight Panel Cable
If I replace the final crossover cable with a straight, change the
foundry to a 10/100 port, and plug the final end into a host NIC
instead of the cisco I get a connection. Crossover cable has been
changed twice now, and the RJ45 GBIC was previously working in a cisco
I am extensively familar (at least I believe I am) with both these
models, and this one has me stumped.
If nobody else can see any configuration errors I guess I'm down to
Cisco Infrastructure Port Recommendation
Configuring auto-negotiation is much more critical in a GE environment
than in a 10/100 environment. In fact, auto-negotiation should only be
disabled on switch ports that attach to devices not capable of
supporting negotiation, or where connectivity issues arise from
interoperability issues. Cisco recommends that Gigabit negotiation be
enabled (default) on all switch-to-switch links and generally all GE
devices. The default value on Gigabit interfaces it auto-negotiation,
but is still a good general practice to issue the following command to
insure that auto-negotiation is enabled:
switch(config)#interface <type> <slot/port>
!--- Sets the port to auto-negotiate Gigabit parameters.
I have not looked at the RFC in a while but I thought when it first came
out that auto negotiation had to be used on GigE.
The Information Technology News Center
RE: Problems connectivity GE on Foundry BigIron to Cisco 2950T sam_ml (Jan 16)