SV: [daniel@netatonce.se: SV: [LARTC] TEQL: 2 Mbit eth1 + 2Mbit eth2 = 1Mbit teql0]

[bert hubert ahu@ds9a.nl]

<PRE>On Tue, Oct 10, 2000 at 06:03:44PM +0200, bert hubert wrote:
&gt;<i> On Tue, Oct 10, 2000 at 04:21:06PM +0200, Daniel Bergqvist wrote:
</I>&gt;<i> &gt; The logs are at <A HREF="http://www.bergqvist.se/teql/.">http://www.bergqvist.se/teql/.</A>
</I>&gt;<i> &gt; 
</I>&gt;<i> &gt; The speed is about 1.3Mbit/s.
</I>&gt;<i> 
</I>&gt;<i> There is lots of packetloss. Also, it is obvious from this dump that
</I>&gt;<i> lan_router is sending both over eth1 and eth2, but that the wan router is
</I>&gt;<i> only receiving on eth2, and not on eth1, or that your dump failed.
</I>

On second thought, there is no packet loss. This is expected behaviour, it
appears, see <A HREF="http://www.kernelnotes.de/kt/latest.html:">http://www.kernelnotes.de/kt/latest.html:</A>

Alexey Kuznetsov was critical of this explanation, and said that multipath
routing worked &quot;perfectly when you need to split load on servers talking to
enough large number of clients. Any
     http server is good example.&quot; He added that Andi's suggestion of the
existing eql, teql and bonding devices, would introcude &quot;even worse problem
of strong tcp reordering. Actually,
     experiments show that load balancing works only in the situations, when
congestion window is bounded by 3 packets. If it is not made artificially,
it occurs automatically on each connection
     after some amount of excessive retransmissions. Total single TCP
connection throughput is never better in this case. Actually, it hints to
the thought that &quot;true load blalancing&quot; has to
     involve tracking connections and avoiding reordering TCP packets.&quot;
There was no reply to this, but there was a bit of implementation discussion
elsewhere, along the lines of Andi's
     explanations. 

----

You might consider using google a bit to find out about packet reordering -
packets arrive out of sequence on eth1 and eth2, which the kernel interprets
as packetloss.

Regards,

bert hubert

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