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Connecting two procurve swithces

William Grossman
Occasional Visitor

Connecting two procurve swithces

I am trying to add on to my network by adding a second procurve 4000M at the end of a 150' cat5e cable and then adding work stations to the second switch. Unfortunately I cannot connect pc's on the second switch to the main network. If I use a small 3com hub everything works fine, but the switch will not work. In searches on google I have found references to Spanning trees and Link aggregation. I haven't found any specific info on how to configure these and the 4000's manual hasn't helped.
Ron Kinner
Honored Contributor

Re: Connecting two procurve swithces

I believe you need a crossover cable to connect two 4000's together. Some of the newer HP switches automatically adjust to compensate for the cable but the install guide for the 4000


specifically lists Incorrect Switch to Switch connections as the first topic under troubleshooting so it appears that this is not the case with the 4000M.

My 3COM hubs have a little switch so you can change the termination of port 24 to fit the cable. If you are using port 24 on the 3COM then that's probably why it works and your 4000 doesn't. Does it still work if you connect it to a port other than 24? If not then you definitely need a crossover cable.

Another possibility I can think of is that autonegotiate is failing on the link when you have two 4000s and not when you have the 3Com. Go into each switch and set the port that connects to the other switch to 100 full and make sure flow control is set the same way on both switches.

If the switch doesn't have a link light on the port you are trying to use then go into the management console and check the status of the port to see if it is linking up OK.

Spanning tree shouldn't stop it from working and Link Aggregation only allows you to use more than one cable to connect two switches.

Of course, make sure you have both switches upgraded to the latest firmware which is C 09.16.



Trusted Contributor

Re: Connecting two procurve swithces

You should definitely use a cross-over cat5e cable to cascade two HP 4000M switches, since there is no MDI-MDIX button on any switch module. (usually, non-modular switches have a push-button near port 24 or 48 that allow you to use this port either for NIC connection -MDI- or switch up-link -MDIX). See MDI(X) Note below.

To obtain a cross-over cable, one end should be terminated as per EIA/TIA T568A (ISDN) and the other should be terminated as per EIA/TIA T568B (AT&T). See the .doc attachment I've send.

In case you can't download or see the attachment, here are the connectorPin-to-cableWire assignments:

T568A (ISDN):

T568A (AT&T):

Pin1 is the RJ45 connector's leftmost pin, as you look at the connector on the golden contacts' side, with contacts pointing upwards (the hole for the cable insertion pointing downwards). Pin8 is the rightmost - using the same view :-)

After crimping the connectors as described above you should check the cable with a tool like "Fluke 650 LAN Cable Meter" and the corresponding terminator (like "Fluke 650R Terminator"). This kind of tools can tell you if the cable is cross-over or strait-through.

For more information, go to:


and fiddle around a little.


MDI(X) Note

There are two types of RJ45 interface. The MDI-X interface is generally used by a hub\repeater, and the MDI is generally a workstation or file server. The difference between the two is that the receive and transmit pairs are swapped which means you must use a cross-over cable when connecting to like devices (MDI to MDI, or MDI-X to MDI-X)