On 2010-08-03, Kevin Chadwick <[email protected]> wrote:
>> All right , let me put it straight , a have a 3G card , a cable with
>> 1M bandwidth , i'd like to take use of them together , that's
>> so-called double routes (maybe load balance) , don't know if it is
>> possible.
>
> I'm pretty sure the trunk interface (roundrobin or loadbalance mode)
> will do what your looking for, if you have an interface for each
> connection? The differing connection speeds, may be a concern however?
>
nope, trunk is layer 2, this situation needs something at layer 3.
ECMP (-mpath) routing table entries may work, or use route-to/reply-to
in PF (which is nice if you want to classify traffic more closely e.g.
send latency-sensitive traffic over cable rather than 3G). you can
probably also do something with rtables in the mix, but i haven't
worked out how yet.
N.B. if your providers follow best practices, typical subscriber
connections will reject packets with the "wrong" source address (i.e. the
source address from the other connection). this is especially likely with
a 3G connection which, in most cases, will be stuck behind NAT, so even
if your provider is too slack to intentionally implement BCP38, it
still won't work. so:
** if you have problems then use tcpdump and look carefully
at which source addresses are used on each interface
(semi-related, uk-based readers might be interested to keep an eye
on aaisp, who do 3g sims and plan on offering routed static IP <and also
l2tp handoff at some time>, i suspect in conjunction with aql/three).
