topic RE: Lossless LACP recovery? in ExtremeSwitching (EXOS/Switch Engine)

Lossless LACP recovery?

Zsolt_Babindai — Wed, 30 Mar 2016 14:48:00 GMT

We configure LAG/LACP with "algorithm address-based L2 lacp" mode and on host side Ubuntu Linux machines are in mode passive from LACP aspect (bond_mode=balance-slb, lacp=passive). However when link recovery happens - one of the links was offline then gets online again - significant packet loss occurs even on the earlier active link which was used for traffic forwarding. Is there any way configuring a lossless recovery with LACP? (Something like this: https://www.ibm.com/support/knowledgecenter/ssw_aix_71/com.ibm.aix.networkcomm/lossless_rcvr.htm)

RE: Lossless LACP recovery?

Henrique — Wed, 30 Mar 2016 17:56:00 GMT

Hi Zsolt,

I don't believe EXOS supports lossless recovery for LACP.

I would recommend you to try some actions (if not yet done) like:

Change the Linux Ubuntu machines from passive to active mode

Change the sharing algorithm in EXOS from l2 to l3_l4 (you will need to delete and create the LAG again)

Change the lacp timeout from long to short

configure sharing lacp timeout short

Note: Since the issue is related when the port goes down/up, LACP timeout might not fix the issue, but I think it's worth a try.

RE: Lossless LACP recovery?

Zsolt_Babindai — Thu, 31 Mar 2016 11:51:00 GMT

Hi Henrique,

Thank you for your response but we have tried as many LACP options and configuration as possible with no luck. We have to conclude that there is no way to change this behaviour.

Br,
Zsolt

RE: Lossless LACP recovery?

Stephane_Grosj1 — Thu, 31 Mar 2016 14:31:00 GMT

Hi,

with 21.1 we are introducing resilient hashing, which might help in your case (if your platform support 21.1). Have a look at it.