3750 connection to 3Com and HP Procurve

[jcowtan]

I have configured a network of 3750s in a hub / spoke design. There are 3 Vlans. The legacy Vlan 200 is configured on all access ports. RSPT+ is configured with hub as root.

The old network is also a hub / spoke design using HP Procurve and 3Com switches. Only one Vlan (default) is on that network.

To migrate, I want to connect the old network to the new using a cross over from two access switches at the hub. This (I hope) will allow the old network trafic to transverse onto the new VLAN 200 (all teh same subnet / broadcast).

When connected I would expect to be able to access devices from either side!

However, when I connected the cable, I was able to ping from the new network to a device initially .... then lost all pings ... and then finally the old network froze!!! When the cable was removed, everything was restored.

The Cisco switch log showed no errors on that port. I tried setting speed and duplex but no change. I turned off RSPT+ for the VLAN 200 but agian no change.

Any ideas on what is causing the HP 3Com network to freeze?

[hadbou]

To fix this issue, try these steps:

Set the speed and duplex to AUTO.

Enable the Auto-Medium-dependent Interface Crossover (MDIX) feature.

When this feature is enabled, the switch detects the required cable type for copper Ethernet connections and configures the interfaces accordingly. Therefore, either a crossover or a straight-through cable can be used for connections to a copper 10/100/1000 or 1000BASE-T SFP module port on the switch, regardless of the type of device on the other end of the connection. The Auto-MDIX feature is enabled by default on switches running Cisco IOS? Release 12.2(18)SE or later. For releases between Cisco IOS Release 12.1(14)EA1 and 12.2(18)SE, the Auto-MDIX feature is disabled by default.