[1598] in linux-net channel archive
Multiple IP routing domains ?
daemon@ATHENA.MIT.EDU (Matthias Urlichs)
Thu Jan 11 21:20:43 1996
From: smurf@smurf.noris.de (Matthias Urlichs)
To: linux-net@vger.rutgers.edu
Date: Fri, 5 Jan 1996 13:11:16 +0100 (MET)
Hi,
A client has a problem: They're an ISP and connect their customers to m=
ore
than one provider.
Solution 1: One dial-in box per provider. Ugly. Expensive. Besides, two
or three boxes with N lines each have much worse availability than one =
box
with 2*N or 3*N lines because often, lines at one box are all full whil=
e
the second has spare capacity.
Solution 2: Hack Linux networking to support more than one IP forwardin=
g
table. Obviously I want to do this cleanly... first idea:
- We don't have one routing table, we have N. One for each routing doma=
in /
provider we talk to.
- We need a flag in the struct rtentry to say which routing domain we w=
ant
to modify. The rt_use field is unused in that context so it could be
recycled, and a RTF_USETABLE flag added.
- Within the kernel, the interface a packet comes in on determines whic=
h
routing table to use for forwarding.
- A firewall table (or something like it) is used to determine which
routing domain to associate a local or incoming packet with.=20
Originally I wanted to use the interface the packet comes in on, but =
that
prevents me from splitting this feature among several machines later =
(one
for the users, one for talking to the providers) and from using other
criteria which routes to use, eg. for sending low-latency packets ove=
r
a different path than high-thruput packets.
Ideas, anyone? Does anybody else need a feature like that?
--=20
Honesty's the best policy.
--Miguel de Cervantes
--=20
Matthias Urlichs \ XLink-POP N=FCrnberg | EMail: urlichs@smurf.=
noris.de
Schleiermacherstra=DFe 12 \ Unix+Linux+Mac | Phone: ...please use =
email.
90491 N=FCrnberg (Germany) \ Consulting+Networking+Programming+etc'i=
ng 42
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Click <A HREF=3D"http://smurf.noris.de/~smurf/finger">here</A>.
