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Procurve spanning tree behavior

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Jani Munne
Occasional Contributor

Procurve spanning tree behavior

I'm considering following installation.
Server with two NICs(Intel Server Adapters), two Procurve 2524 switches and spanning tree enabled. In those swithces would have ProCurve 100/1000-T Transceiver module.I would put one of those NICs to switch A and the other one to switch B.(Those switches are of course connected together)NICs are part of fault tolerance team.

Can spanning tree handle this ok?
Ron Kinner
Honored Contributor

Re: Procurve spanning tree behavior

Spanning tree is not a problem. It just wants to be sure there are no loops which could cause a broadcast storm. It does this by sending litle packets called BDUs out all ports and listening for them to come back to it (or for other switches' BDUs so it can figure out the topology in order to avoid a loop). Since it won't get BDUs back from either port it will decide that both ports can be allowed to connect to the switch.

The Intel setup should work OK unless you are trying to use the Cisco option. The generic Intel option just sends on both ports and receives on one (with auto failover to the other if the first one fails). (No special trunking or tagging is required on the switch side.) The Cisco option is smarter and will transmit and receive on both so it has a bit more throughput but requires some help on the switch side. HP switches do support it but I'm not sure that it will work when split over two switches. (Doesn't seem too likely but who knows?)


Re: Procurve spanning tree behavior


I think you are right. HP switches can handle trunking streams from servers but only over the same switch.

To answer the original question I also agree with Ron in that what you suggest would work. I do not know the Intel Fault Tolerance setting but with HP there are four settings.
Fail on fault - Switchs to backup nic when it fails
Smart switch - Switches to backup nic but goes back to primary when it comes back online
Load Balance - Goes out on all NICs but in on one (smart switch built in)
Switch Assisted load balance - Out on all NICs and in on all NICs (this is what Ron was mentioning)