SLM2048 and LACP

eric_brophy · ‎03-22-2010

Just bought an SLM2048 and have been trying to get link aggregation with LACP working so that I can get some VMWare ESXi nodes a fatter network pipe.

If I do NOT enable LACP while making the LAG (using default STATIC mode), the LAG looks good (link status UP) and the nodes and interfaces connected to the LAG ports can send traffic through the switch and communicate just fine.

If, however, I enable LACP while creating the LAG, the link status goes down and I lose all communication to/from the nodes connected to those same ports.

Am I overlooking something really obvious?

Thanks

alissitz · ‎03-25-2010

Hello,

I do not think you are missing anything.

LACP will negotiate LAGs, however in this case you have manually set everything. If it is up and good, you are good. Pass some traffic and check the interface stats to make sure everything is fine. For sure make sure you run this through some tests before going live ...

A nice feature of LACP is that it will 'barf' at you if the settings are not the same on either side; misconfig. I will say however, that we have seen some cases where everything is fine and LACP just does not want to play nice with every vendor / NIC.

If all is well, and you have hard coded the settings you do not need LACP.

HTH,

Andrew Lissitz

eric_brophy · ‎03-25-2010

thanks for the response Andrew.

with LACP checkbox checked (enabled) on the LAG i can't test anything since the port group is down on the switch. the nodes are still lit up and showing a good 1000/FULL network connection, but all traffic ceases to flow since the switch has downed the LAG.

simply removing that LACP checkbox on the LAG fixes the problem.

so you're saying LACP is on by default and no checking of any checkboxes is required? how do i know it's actually using LACP if the checkbox isn't checked? Also, i'm not seeing any sort of balancing of the load across multiple ports in the LAG...just a single port for the most part.

anyone write up some better docs for this switch somewhere? i'm not against reading more about it...the docs that came with the switch haven't helped understand how it works at all.

thanks again

SLM2048 and LACP

Cisco Business Product Family

Cisco Switching Product Family