Switch to Switch = Crossover?

I know that's conventially how it's tought but I've also heard some switchs can auto detect the cabling and it doesn't matter. I just wanna be sure before I purchase a bunch of cabling for my home lab. I have 4 routers and 3 switches (2x2950's, 1x3550).

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dynamik

This is the technology: Auto-MDIX - Wikipedia, the free encyclopedia

I'm not sure if those switches support it or not. You should probably just go with crossover to be safe.

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networker050184

Read this.

miller811

2950 and 3550 devices will require a cross over if interconnected.
like devices (router to router) - (switch to switch) - (pc to pc) typically require a crossover cable.

Newer Cisco switches 2960, 3560 switches do not require a crossover.

Given the cost difference between the devices, buy or build a crossover.

Turgon

We did a trunk between two 6000's the other day and the straight cable worked. I imagine it was the autodetect thing. Saved us rummaging for a crossover. I don't think one was to be found nearby *shrug*

EdTheLad

3550 supports mdix, 2950 doesn't.So you can connect between the 3550 and 2950's using either straight or crossed and between 2950s with crossed only.

miller811

EdTheLad wrote: »

3550 supports mdix, 2950 doesn't.So you can connect between the 3550 and 2950's using either straight or crossed and between 2950s with crossed only.

Perhaps you could enlighten me Ed?
I have 2 3550 and 2 2950 switches in my home lab.
They will only connect with a crossover cable.

What is the secret oh wise one?

ElvisG

I thought a cross-over was required whenever like devices are connected together.

kalebksp

ElvisG wrote: »

I thought a cross-over was required whenever like devices are connected together.

Not if they support Auto-MDIX (Automatic medium-dependent interface crossover), which will automatically detect if a crossover is necessary and change the ports send and receive wires appropriately. For any Cisco testing you do, unless explicitly stated, assume that Auto-MDIX is not in use.

EdTheLad

miller811 wrote: »

Perhaps you could enlighten me Ed?
I have 2 3550 and 2 2950 switches in my home lab.
They will only connect with a crossover cable.

What is the secret oh wise one?

Its only supported on fa0/25 on my 3500-24T

.Consider yourself enlightened.

Switch1#show interfaces transceiver properties
Name : Fa0/1
Administrative Speed: auto
Administrative Duplex: auto
Administrative Auto-MDIX: N/A
Administrative Power Inline: enable
Operational Speed: 100
Operational Duplex: full
Operational Auto-MDIX: N/A
.
.
.
.
Name : Fa0/25
Administrative Speed: auto
Administrative Duplex: auto
Administrative Auto-MDIX: N/A
Administrative Power Inline: enable
Operational Speed: auto
Operational Duplex: auto
Operational Auto-MDIX: enable

Name : Gi0/1
Administrative Speed: auto
Administrative Duplex: auto
Administrative Auto-MDIX: N/A
Administrative Power Inline: N/A
Operational Speed: auto
Operational Duplex: auto
Operational Auto-MDIX: N/A

Name : Gi0/2
Administrative Speed: auto
Administrative Duplex: auto
Administrative Auto-MDIX: N/A
Administrative Power Inline: N/A
Operational Speed: auto
Operational Duplex: auto
Operational Auto-MDIX: N/A

miller811

EdTheLad wrote: »

Its only supported on fa0/25 on my 3500-24T .Consider yourself enlightened.

Thanks dude..... glad to know I was not losing my mind.....

Miikey87

Dont forget your cross over PC -> Router!

pitviper

I found out the hard way that Auto-MDIX is nullified when you force the speed and duplex on the port. There must be a way around it but it was easier for me to plug in a crossover cable than it than it would have been to explain why the network was down

tiersten

pitviper wrote: »

I found out the hard way that Auto-MDIX is nullified when you force the speed and duplex on the port. There must be a way around it

Nope. Disable autoneg and you lose auto-MDIX. It uses the same process to work out whether it needs crossover or straight.

Turgon

tiersten wrote: »

Nope. Disable autoneg and you lose auto-MDIX. It uses the same process to work out whether it needs crossover or straight.

Now THAT makes a lot of sense.

jbaello

dynamik wrote: »

This is the technology: Auto-MDIX - Wikipedia, the free encyclopedia

I'm not sure if those switches support it or not. You should probably just go with crossover to be safe.

Where are you getting your cables from? Check out HDMI Cable, Home Theater Accessories, HDMI Products, Cables, Adapters, Video/Audio Switch, Networking, USB, Firewire, Printer Toner, and more! if you haven't yet.

Hey thanks for the link they have a very nice S&H, and good price for bulks, just purchased abunch of crossovers, I will return my 6 $ cables I got from Fry's ugh...