Re: How usable is agr(4)?

[der Mouse <mouse%Rodents-Montreal.ORG@localhost>]

>> Perhaps agr should have a mode where it really does load-balance, eg
>> by queueing outbound packets onj whichever interface has a shorter
>> queue, instead of doing crude approximations based on hashing?
> This is what IFF_LINK0 does I think:
>      link0   Use the round-robin distribution algorithm.

Ooo, that's close.  Close enough to be useful in almost the same set of
circumstances true load balancing would be.  (I can easily imagine an
application where, for example, packets alternate between large and
small, in which case round-robin distribution with two interfaces will
send substantially more traffic through one member than the other.  But
I suspect that such cases are rare enough to be considered
pathological, ignorable unless you happen to be stuck with one.)

>      Don't use it unless you're really sure, because it violates the
>      frame ordering rule.

IP has never promised packet order preservation; anything that breaks
in the presence of packet reordering is already broken and deserves to
be rendered _visibly_ broken.

Of course, there are plenty of things for which packet ordering is a
performance issue even if not a correctness issue....

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