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Re: 2 ADSL / load balancing problem(?)

On Wed, Oct 23, 2002 at 09:15:32AM -0700, Scott Francis wrote:
> [original post]
> I have 2 ADSL lines as uplink for small office, how can I set OpenBSD
> to use both of those for outgoing/incomming traffic?
> [my reply]
> Suggest you search the archives; this question (load balancing traffic) comes
> up periodically. You may also want to check out altq(9), and keep in mind
> that balancing ingress traffic is not possible with the setup you have.
> Balancing egress traffic may be possible, in a way, through use of
> altq/pf/nat and a pair of gateways.
> [claudio jeker's response]
> > First normaly you should not have excessive ingress traffic on ADSL
> > because this will also reduce the egress traffic.
> Not sure quite what you're trying to say here ...

It's a not about the nature of ADSL, if you have a lot of ingress traffic
your egress traffic will suffer because the smaller pipe of the ADSL link
is filled. 
In other words:
ADSL works great for downloads but if you have a lot of uploads
it will slow down the download speed to.

> > A simple way to load balance ingress traffic would be bgpdns
> > (http://www.bgpdns.org). Have a look at the RIPE 41 Presentation for more
> > info.
> >
> > For egress traffic a bgpnat is in development but bgpnat uses FreeBSD and
> > their userland natd because complex loadbalancing does not belong into the
> > kernel. The upcomming natd form FreeBSD has already simple round robin
> > based egress load balancing. See http://diehard.n-r-g.com/stuff/freebsd/
> >
> > It should be no big problem to add a similar balancing extension to pf but
> > I did not have time to dig through the pf code.
> For the situation described by the OP, I don't think ingress traffic is
> really a concern. It sounded (to me, anyway) like he had a standard small
> office setup with 2 provider lines instead of 1. Unless the OP was planning
> some kind of hosting or other server-based stuff running off those 2 lines,
> balancing egress traffic via existing tools should be sufficient.

This section was mainly for the archive. This question comes in some
flavour all month on this list.

> [S9 <km_(_at_)_themcminns_(_dot_)_com> response to Claudio]
> > >A simple way to load balance ingress traffic would be bgpdns
> > >(http://www.bgpdns.org). Have a look at the RIPE 41 Presentation for more
> > >info.
> >
> >or just use round robin if all you want it load balancing.
> Again, from what the original post said, there was no mention of trying to
> _serve_ from this office network - merely using two providers as a very basic
> type of network redundancy, similar to what several other people have asked
> about over the last year or two (frequently in conjunction with questions on
> rate limiting as well).
> Perhaps the OP could clarify his setup and exactly what he was trying to
> accomplish?

IMHO OP would like his two NAT-ed ADSL links to load balance the traffic.
If this is the case you need an intelligent nat service that can balance
connections (e.g. with round robin or a better algorithm). The idea is
simple, for each new state entry the outgoing interface is selected by
some magic and used for the complete session.

Setting up bgp with some PI IP space just for two ADSL is exagerated and
at least RIPE will not give you the IP space for that.

:wq Claudio