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bl20p g3 servers

Paul DeVincentis
Occasional Advisor

bl20p g3 servers

I have a weird one. I have 3 windows blade servers connected to a 10/100 3Com switch (from back of the enclosure). The network properties of the NIC state I am connected with 1GB/sec. I would like to get full 1GB/sec uplink to the servers. So, I moved the ethernet cables to a 10/100/1000 3Com switch on the fly. When I did this, the 3Com switch froze. I looked at the ports (set to auto sense) and the GBE2 interconnect switches on the enclosure are set to auto sense. Why is the 3Com switch locking up? I've tried other 10/100/1000 switches to verify. When I plug the ethernet cables back into the 10/100 switch everything works fine. Do you have to power down the blade servers when you disconnect/connect from the GBE2s?

Thanks,

Paul
6 REPLIES
Marek Nelec
Honored Contributor

Re: bl20p g3 servers

Hi
You absolutely don't have to power down the blades. When connected to 10/100 port of the 3Com switch do you use a crossover cable with only 2 pairs crossed by any chance? If so try connecting the 10/100/1000 uplink using normal CAT-5/6 patch cable.
Paul DeVincentis
Occasional Advisor

Re: bl20p g3 servers

Marek,

Not using cross-over cables at all.

Paul
Paul DeVincentis
Occasional Advisor

Re: bl20p g3 servers

Marek,

Should you connect all 8 RJ45 ports with a patch cable? I am only using two per switch.

Paul
Marek Nelec
Honored Contributor

Re: bl20p g3 servers

i don't know what kind of 3Com switch you are using, but you should connect more than 1 port between any two switches only if:
1) The switches support and have enabled Spanning Tree Protocol. Otherwise you will create loop between the switches.
2) Both switches have capability of port aggregation (there are several types of aggregation methods, and they must support the same method), and both switches have configures port groups.
3) In case you have unmanageable 3Com switch, or you are unsure what IEEE standards it can support, use only one link between switches.
Paul DeVincentis
Occasional Advisor

Re: bl20p g3 servers

Marek,

We use 3Com SmartSwitches. the 4900 series. I'm not sure if spanning tree is turned on. I will have our networking team check that for me.

Paul
Marek Nelec
Honored Contributor

Re: bl20p g3 servers

AFAIK both 3Com 4900 series switches and p-class GBE2 switches support static IEEE 802.3ad trunking, but you must configure port groups on both switches. If you have a networki ng team - let them do it :)