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Link Aggregation Myths and inaccuracies

ssAPT
Occasional Advisor

Link Aggregation Myths and inaccuracies

Hi

Could someone please clear up the misunderstandings regarding link aggregation specifically around LACP. Certain articles on the net imply that LACP can be either static or dynamic while other articles speak about LACP being dynamic only and that static link aggregation is something like HP Trunk.

So which is it ? Is LACP either static or dynamic (In which case what are the differences ?) or is LACP dynamic only.

Thanks
4 REPLIES
ssAPT
Occasional Advisor

Re: Link Aggregation Myths and inaccuracies

Another question:

I've also noticed that I can issue the LACP Active or LACP Passive commands to a standard interface but not to a trunk interface. Why is this ? what mode does the trunk interface operate in then ?

thanks
Olaf Borowski
Respected Contributor

Re: Link Aggregation Myths and inaccuracies

ProCurve lingo:

Static trunk = force link aggregation, no protocol used.

Static LACP: You tell which ports are used to build a trunk. LACP protocol is used to negotiate.

Dynamic LACP: Port can be dynamically assigned to a trunk group without user intervention or "pre-definition"

Active LACP = you speak and listen to LACP BPDUs.

Passive LACP = you only respond if you are asked to (in other words, one side has to initiate or be active). Active/passive works, Active/Active works, passive/passive doesn't work.

Hope this helps
ssAPT
Occasional Advisor

Re: Link Aggregation Myths and inaccuracies

Hi

Yes thanks for clearing that up.. still boggles me mind though why a port thats not in a trunk can have active/passive options configured however once a trunk is created you cannot set active/passive options on the trunk (i.e TRK1 , TRK2 etc)
Ugo Bellavance (ATQ)
Frequent Advisor

Re: Link Aggregation Myths and inaccuracies

The active and passive options are for the negociation of the LACP trunk. In TRUNK mode, there is no negociation, so no active or passive options.