is odd number of links in lag group ok

Saku Ytti saku at ytti.fi
Wed May 16 13:10:39 UTC 2018


This is implementation specific.

Consider hash result returning range 0-15.

Then number of port count as divisor of 16/n must result in an integer value.


To workaround this issue, you either have larger range of hash
results, in which case unequal distribution has small bias, or you
have different hash functions depending on port count so that that
hash returns appropriate range for given port count.

Certainly solvable problem, and generally non-issue.


On 15 May 2018 at 21:46, Adam Atkinson <ghira at mistral.co.uk> wrote:
> On 15/05/18 16:28, Mark Tinka wrote:
>
>> That said, an even number of links just leaves the warm & fuzzies turned
>> on :-)...
>
>
> Well, power of two, surely? 6 is even, but is not a "good" number of links
> for a lag group.
>
> (Extreme X8 supports up to 64 links in a group, and Enterasys up to 127 if I
> recall correctly. Though Enterasys, unusually, seems to support round-robin
> load balancing in which case the argument for powers of 2 numbers of links
> ceases to make sense.)



-- 
  ++ytti



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