Faster 'Net growth rate raises fears about routers

Yakov Rekhter yakov at juniper.net
Tue Apr 3 15:27:54 UTC 2001


Greg,

> On Tue, 3 Apr 2001, RJ Atkinson wrote:
> 
> > At 08:37 03/04/01, Greg Maxwell wrote:
> > >Replace the internet with a highly aggregated IPv6 network 
> > >which uses transport level multihoming and you gain a factor 
> > >of 1000 improvement at core routers (and 100,000x further 
> > >from the core where you no longer need to be default-free) 
> > >and still have the oppturnity for a further 5x by going
> > >to a state-of-the-art CPU (providing that your cpu speed 
> > >reasoning is valid).
> > 
> >         Precisely which "highly aggregated IPv6 network
> > which uses transport level multihoming" is one talking about ?
> > What's the RFC on this ?  
> 
> It's possible to 'solve' these problems in the future:
> Forbid IP level multihoming for IPv6 which crosses aggregation boundaries.
> I.e. absolutly no multihoming that inflates more then your providers
> routing tabling, connect to whoever you want, but no AS should emit a
> route for any other AS without aggregating it into their own space without
> a special agreement of limited scope (i.e. not globally!)

Who is going to "forbid" this ? And who is going to enforce this ?

> >         AFAIK, IPv6 multihoming is identical to IPv4 multihoming,
> > with all the same adverse implications on the default-free routing 
> > table  -- hence the creation of an IETF MULTI6 WG to try 
> > to change this.  If I've missed some recent advance in the 
> > IETF specifications, please share the details (preferably citing 
> > RFC and page number :-) with the rest of us.
> 
> IPv6 multihoming *is* the same.
> 
> What I argue is that: Routers are the wrong place to do multihoming for
> anything but Tier-1 connectivity. Multihoming belongs in the end node.
> 
> SCTP (2960) is a transport level protcol which offers what amounts to a
> superset of TCP. One of it's features is multihoming (2960; section 6.4).
> 
> With such a protcol it is possible to accomplish all of the realibility
> benifits of IP multihoming while achieving much greater scalability,
> flexibility, and performance.
> 
> We need to stop looking at IP addresses as host-identifyers (thats what
> DNS is for) and look at them as path-identifyers.

Perhaphs. But (stating the facts) for now, both in IPv4 *and* in
IPv6 IP addresses carry dual semantics - host-identifiers (aka
end-point identifiers) *and* path-identifiers (aka locators).

Yakov.




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