On Wed, 4 Aug 2010 09:35:27 +0000 (UTC) Stuart Henderson <[email protected]> wrote:
> 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). > right you are (ppp), Sound like this will help you deal with the speed/latency/expense probs too. Correct me if I'm wrong again but another option for redundancy would be to use two boxes for the connections with a trunk in failover mode. (I'm guessing you don't want to increase bandwidth, if you've chosen 3g?, or is this just a laptop or something?)
