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Strange LACP/Trunk problem

Sam Fewster
Occasional Visitor

Strange LACP/Trunk problem

I have an HP 2650 Switch, with a static LACP trunk running over ports 49-50 to a Dell switch. There are a few devices plugged into the switch also.

The problem I am having is that when both ports (49 & 50) are up, some IP addresses cannot be found from the Dell switch (Ping, traceroute e.t.c). When one port is physically unplugged or disabled, everything works fine again.

I have tried as many configurations as I can think of; Static, Dynamic, Normal Trunking. I have also tried setting the trunk up on different ports, all with the same result. Any Ideas? Thanks!
4 REPLIES
Matt Hobbs
Honored Contributor

Re: Strange LACP/Trunk problem

What sort of trunking is configured on the Dell?

Not being familiar with the Dell switches at all, are you certain that their 'trunking' is the same as ProCurve trunking - i.e. port aggregation?

Trunking can either man VLAN tagging, or port aggregation depending on the vendor.
Sam Fewster
Occasional Visitor

Re: Strange LACP/Trunk problem

Hi, thanks for the quick reply. The Dell switch is configured properly for port aggregation. The configuration is similar to IOS, using the "channel-group 1 auto" command. "show lacp" on the HP switch shows LACP enabled, and partner YES for both ports 49 and 50.

Here is a snapshot of my HP config. Port 50 is down as this is a quick fix for the problem:

interface 49
no lacp
exit
interface 50
disable
no lacp
exit
trunk 49-50 Trk1 LACP

Thanks
João Pedro Cruz
Occasional Visitor

Re: Strange LACP/Trunk problem

Hello Sam,

I crossed with your post and I have similar issue between HP 2650 and server.

Did you found the solution for your problem?

I also tried several settings without success...

Thanks.
Ben Dehner
Trusted Contributor

Re: Strange LACP/Trunk problem

I can't offer a solution, but I'll point out that Matt's question "What sort of trunking is configured on the Dell?" was not answered.

There are 3 protocols that I know of for port aggregation. The HP switches use LACP, which is an IEEE standard. The others are EtherChannel, which is a Cisco proprietary standard, and MultiLinkTrunk (MLT), which is a Nortel proprietary standard. If the Dell/Cisco switch is (behind the scenes) using EtherChannel and not LACP, then you are going to have problems. Something to investigate.
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