[LARTC] Re: ESFQ Modification

[Nuutti Kotivuori <naked@iki.fi>]

Robert Kurjata wrote:
> Some time ago I faced a problem in limiting traffic on host with
> multiple uplinks. Since all the stuff worked nice seemed that there
> will be no problems. But then I realized that P2P users are smart
> enough to bypass limits as sfq doesn't give fair sharing in this
> case (thousands of connections from one user versus few from the
> other).  I tried IMQ but it's instability in my configuration was
> painfull.  So I made something like that:
>
> 1. i use IPMARK patch for the iptables to mark all the connections
> in P2P related class depending on source IP (i use SNAT),
> 2. modified ESFQ to create hash depending on FWMARK instead of src
> ip 3. and it worked. So I have uplink policy based on source ip in
> snat-ed environment without using IMQ.
>
> I'm looking for the opinions, cause I may be wrong in this.
> Patch for the files below, cause it's short

Quite an unorthodox solution, I must say. But I guess it's as valid as
anything is. SFQ and ESFQ are usually for situations where you have a
large amount of connections (hashes) that you just cannot track
invidually. Hence stochastic - and hence the options for perturbation
and so. If there's only a few hashes, as most likely is in your NFMARK
case, most of the time they will hit separate hash buckets - but on
some perturbation, they might hit the same hash buckets again and
fairness is not achieved.

The patch as it was by my brief peek, looked rather okay, though.

Have you looked in to the WRR scheduler? It is meant to give an equal
share of bandwidth to all 'local' machines with weighted round robin
scheduling and sounds like exactly what you are looking for.

-- Naked

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