Comware

Hello,

we want to do link aggregation (2 ports, i.e. both switches connected by two cables) between two switches of type 1810-24G v2. In some posts (not necessarily related to the 1810 series) I read that

a) one switch has to be LACP active, the other one LACP passive; but that didn't work for us. Is there a tutorial/documentation on how to correctly establish LACP between these two switches?

b) when using LACP there is the danger of switch loops. What are switch loops? And how can they be avoided? Is ist necessary to activate STP on the trunk?

Thanks for your help.

Chris

P.S. This thread has been moved from ProCurve / ProVision-Based to web & unmanaged. - Hp Forum Moderator

A switch's job is to

 - accept ethernet frames,

 - read the source MAC address in the frame header

 - record that MAC address against the port it came in from in something called the MAC-address table

 - read the destination MAC address in the frame header

 - lookup the destination MAC address in the MAC-address table and find out what port to send it out

 - send ethernet frames out that port

 - (rarely) when there is no entry in the MAC-address table, send the frame out ALL switchports EXCEPT the port is was received on

 - forward broadcast frames out ALL switchports EXCEPT the port it was received on

It also does stuff with VLANs and multicast, but you can worry about that later.

So, think about it - you patch two switches together, TWICE - you now have a loop: if a broadcast frame is received from a device, it can go round and around. That's where spanning-tree comes in - it disables the loop.

However, link aggregation combines the two links as a single virtual link, and intrinsically eliminates the loop.

Link aggregation is way better than spanning-tree, if it is available.

Vince,

thanks for your answer!

As regards LACP between the switches: Do you know what I should select as configuration: LACP passive - LACP active; LACP active - LACP active, ... ?

Thanks!

I'm not familiar with 1810s, but what I do know is that with every new combination of vendors you have to get the correct config by trial and error.

They all use different words to describe it.

Basically, you want "static", but if the only choices are something like "active" and "passive" then you need at least one side to be configured as "active".