Re: Routing over multiple interfaces

[David Woodhouse <dwmw2@infradead.org>]

On Mon, 2010-11-01 at 22:35 +0100, Eric Dumazet wrote:
> 
> David W. probably wants to use teql or some bonding ?
> 
> # tc qdisc add dev ppp0 root teql0
> # tc qdisc add dev ppp1 root teql0
> # ip link set dev teql0 up
> # ip route add default src 90.155.92.214 dev teql0

That works; thanks. Or it should do... there's a slight complication
right now in that one of my lines is actually routed through a separate
ADSL<->Ethernet box, because one of the ports on my Solos card is a bit
shagged and syncs a lot slower than it should. So it's actually eth1 and
ppp1 that I'm sharing. That should be fixed relatively soon as they're
sending me a new box.

There's a minor issue with this setup though — ideally, any given TCP
connection would tend to use the *same* interface as much as possible,
and only 'overflow' onto the other interface if it's actually saturating
the uplink on the first. That would tend to reduce the amount of packet
re-ordering. At the moment it will split outbound packets over both
lines even when they're relatively idle, introducing packet re-ordering
where it wasn't really necessary.

That said, the world is supposed to cope with packet re-ordering, so I'm
not going to lose a lot of sleep over it. And I have a feeling the
downstream link from the ISP does it exactly the same.

-- 
dwmw2