a very wired thing !!!!!!

CCIE_2011

Morning all ... just a couple of days take the BCMSN

today will doing some labs. I hard code two ports on different switches with different speed

[SW] (speed 100, full duplex)

( speed 10, full duplex) [SW]

now shouldn't i get speed mismatch ... atleast the link should come up .... But unfortunatly the link is totally down at both end... i never thought the link won't come up totally?!!
I'm using 3560 switchs. Also tried it on 2900XL, I have only one, Just connected back to back to try this .
PS: also tried half duplex ... same thing.

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Comments

Rearden

Speed matches are a deal breaker. The link simply won't come up.

CCIE_2011

Rearden wrote:

Speed matches are a deal breaker. The link simply won't come up.

So we don't get any indicator about this ..... ?
I was struggling for an hour .... think that the port is malfuntioning. then found that speed is not the same !

Rearden

I don't know what type of error messages you get on a speed mismatch, although the link won't come up as far as I know.

tech-airman

CCIE_2011 wrote:

Morning all ... just a couple of days take the BCMSN

today will doing some labs. I hard code two ports on different switches with different speed

[SW] (speed 100, full duplex)
( speed 10, full duplex) [SW]

now shouldn't i get speed mismatch ... atleast the link should come up .... But unfortunatly the link is totally down at both end... i never thought the link won't come up totally?!!
I'm using 3560 switchs. Also tried it on 2900XL, I have only one, Just connected back to back to try this .
PS: also tried half duplex ... same thing.

CCIE_2011,

What kind of patch cable are you using between the two switches?

CCIE_2011

tech-airman wrote:

CCIE_2011 wrote:

Morning all ... just a couple of days take the BCMSN

today will doing some labs. I hard code two ports on different switches with different speed

[SW] (speed 100, full duplex)
( speed 10, full duplex) [SW]

now shouldn't i get speed mismatch ... atleast the link should come up .... But unfortunatly the link is totally down at both end... i never thought the link won't come up totally?!!
I'm using 3560 switchs. Also tried it on 2900XL, I have only one, Just connected back to back to try this .
PS: also tried half duplex ... same thing.

CCIE_2011,

What kind of patch cable are you using between the two switches?

Cross

Cucumber

CDP should inform you about the mismatch
Try
duplex auto

And the link should come up

Edit: Oh if that doesnt work I would check into a BPDU/port blocking thing

dtlokee

Cucumber wrote:

CDP should inform you about the mismatch
Try
duplex auto

And the link should come up

Edit: Oh if that doesnt work I would check into a BPDU/port blocking thing

CDP can't help with a speed mismatch which is what he had. When there is a speed mismatch the keepalives don't work correctly so the line protocol can't come up, so no CDP.

Cucumber

I stand corrected.
CDP informs when there is a duplex mismatch not when there is an speed mismatch.

Netwurk

Looks like he's purposely making the speeds and/or duplex mismatch

I'm assuming he knows how to fix things, I think he's just asking why it behaves the way it does with the various settings.

Here's a link with all kinds of mismatch scenarios for ya

http://www.cisco.com/warp/public/473/46.html

Connecting a 2900 to a 3560, you would of course use

duplex auto
speed auto

or

duplex full
speed 100

or

duplex auto
speed 100

or

duplex full
speed auto

anything else just ain't gonna work

CCIE_2011

Netwurk wrote:

http://www.cisco.com/warp/public/473/46.html

thanks for the link dude