[svlug] multiple ricochet wireless router?

Anmol Khirbat anmol at teknema.com
Sat Mar 10 17:27:01 PST 2001


On Sat, 10 Mar 2001, Joey Hess wrote:

> Anmol Khirbat wrote:
> > With all the modems plugged into a single box, multilink PPP is a
> > possibility. Your kernel or ppp modules must be built with PPP Multilink
> > support. You also need a version of pppd which supports the mp stuff, pppd
> > 2.4.x for instance.
> > 
> > The catch is that multilink PPP must be supported by the other end too.  
> > I guess getting all this to work is a long shot.
> 
> With ricochet modems, as far as I know, the "other end" of the ppp
> connection is the modem. 

My end of the ``connection'' is a ``PPP network interface''. The other end
has to be one too. 

> These devices do not speak ppp over the air, they use "lightweight
> ethernet protocol", or something like that (I forget what it's
> called).

It's true that PPP frames don't go over the air, but whatever goes over
the air probably does encapsulate PPP frames in some way.

I imagine that the linux kernel has nothing to do with what goes over the
air.

> The ppp interface is presented to you by the modem itself.

I believe it would be more accurate to say that the modem looks like a
serial device to the kernel.

> What you want is a feature of linux kernels that allows you to bring
> up multiple interfaces and set up multiple defaults routes, one
> default route to each interface. 

Linux does let you set up multiple default routes. According to RFC1122,
the IP layer MUST support multiple default routes.

> Then linux does some sort of per-connection load balancing, assigning
> each new connection to an appropriate interface (it may be as dumb as
> a round-robin, or it may be more intelligent, dunno). 

RFC 1122 also suggests a round-robin, among other things, to select a
default router.

I have absolutely no idea how Linux deals with multiple default routes :-)

bye :)
Anmol










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