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Switches, Hubs, and Modems
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What HP switches work w/IBM cable

Ove Bristrand
Occasional Advisor

What HP switches work w/IBM cable

I have several customers that still for some years will be using IBM Cabling system. They need 100TxBaluns to convert to RJ-45. The problem is that most ethernet switches do not detect if the balun is pulled out and keep the port open. I know that HP 2524 does handle it. What other Procurve switches do that?
6 REPLIES
Arimo Laine_2
Valued Contributor

Re: What HP switches work w/IBM cable

Hi.

There's nothing special in 2524 to handle that... just enable STP, that should do the trick on any switch.

HTH,
Arimo
Ove Bristrand
Occasional Advisor

Re: What HP switches work w/IBM cable

No that does not do the trick, the config you have to do in the 2524 is fault detection to high. The problem with the baluns being pulled out at the user side is that by design the transmit and recieve cables are looped. The switch has to detect this as a faulty cable situation! This state has nothing to do with STP since this is a Layer 1 issue.
SCOOTER
Esteemed Contributor

Re: What HP switches work w/IBM cable

First I need to agree with Arimo. If you run RSTP and pull out the balun the switch detects a loop. This is not the case when you are running STP.

Strictly speaking HP does NOT support IBM Type I Cabling (150 Ohm) , only 100 Ohm UTP or STP. However you can make it to work when
indead using Balloons which convert the 150 Ohm impedance to 100 Ohm.
Depending on the type of balloons used this works or not as not all balloons are equal. Requirement is that the balloons must be
marketed as 10/100 Balloons.

Furthermore HP is willing to support IBM Type I cabling when:

Using a Cat-5 cable tester to test the Type 1 cable (and baluns, and patch cables, etc) from the end that connects to the ProCurve switch to the end that connects to the remote device. If that combination of cables/adapters performs according to Cat-5 specifications, then HP will support it. If it does not perform according to Cat-5 specifications, then the customer should expect that cabling to cause problems when used with
any 10/100Base-T equipment.

The same story applies to other exotic cabling.
Ove Bristrand
Occasional Advisor

Re: What HP switches work w/IBM cable

Some switches does not have RSTP and some customers are still reluctant to run RSTP. The problems are still with the baluns when they are pulled out at the user side, some switches does not detect that the cable is looped. As I said the HP 2524 does do that. I have custs with HP 4000 switches that want to use them on IBM cabling system. Otherwhise they will stay with Roken Ring, especially now when you can buy Token Ring NICs for less than 50 USD.
Arimo Laine_2
Valued Contributor

Re: What HP switches work w/IBM cable

Hi.

If the switch doesn't support RSTP, that's no problem... as the workaround only works with STP, not with RSTP.

Arimo
Ove Bristrand
Occasional Advisor

Re: What HP switches work w/IBM cable

RSTP or STP does not have any effect on this we have already tried that. It does not eliminate the problems with baluns being pulled out at the user side. The switch has to detect the situation as a cable fault(=layer 1). STP/RSTP is layer 2 functions. I will look for other manufacturers than HP to solve the problem for my custs.