Many routers do not rehash everything when a link breaks. Doing so would disturb flows that were not broken, causing possible misordered packets or jitter. The flows on the broken link will get rehashed, of course. Note that even if a hash function can distribute the flows evenly, you may get some heavy flows, so you need to expect some imbalance. Regards, Jakob -----Original Message----- From: Ben Cannon <ben@6by7.net> It will work fine if you have a good modern router. Consider this; all evenly grouped LAGs are odd in their failed conditions. -Ben

On May 15, 2018, at 8:28 AM, Mark Tinka <mark.tinka@seacom.mu> wrote:

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On 15/May/18 17:20, Jared Mauch wrote:

Much of this depends on the hardware, software and what hashing is used inbound outbound traffic directions, etc.

It will likely work the way you expect, but one may be warmer than the other if traffic ends up overloading a single bucket in the hash.

We haven't had a major issue when loading traffic over even or odd links. If you have decent hardware and software, it should all be fine, particularly if your traffic is all or mostly IP.

If you've got non-IP traffic in there, and your box cannot look into the payload to determine entropy, then things could get interesting. But this will happen even when you have even links... it's not anything specific to how many member links you have in the LAG, but rather, the router's need to maintain per-flow load balancing with limited information beyond Layer 2 data.

That said, an even number of links just leaves the warm & fuzzies turned on :-)...

Mark.