Implementations/suggestions for Multihoming IPv6 for DSL sites

Mark Andrews marka at isc.org
Thu Apr 7 20:34:37 CDT 2011


In message <4D9E27A5.3040108 at forthnet.gr>, Tassos Chatzithomaoglou writes:
> 
> Michel de Nostredame wrote on 07/04/2011 22:30:
> > On Thu, Apr 7, 2011 at 2:27 AM, Daniel STICKNEY<dstickney at optilian.com>  wr
> ote:
> >    
> >> I'm investigating how to setup multihoming for IPv6 over two DSL lines
> >> (different ISPs), and I wanted to see if this wheel has already been
> >> invented. Has anyone already set this up or tested it ?
> >>      
> > When you talking about "two DSL lines", I assume this is mainly for
> > office / residential environment to have redundancy and/or increase
> > uplink availability.
> >
> > In this environment, BGP exchanges with uplink ISPs for multihoming
> > usually is not an option. One reason maybe cost, another reason maybe
> > ISP doesn't like to setup BGP with a DSL customer. At least in my
> > case, reason #2 always prevent my customers to setup BGP with uplink
> > ISPs.
> >
> > As Seth pointed out SHIM6 is still an academic exercise, my
> > experiences to resolve this needs at this moment is leveraging NAT66,
> > as what we did in IPv4 world. I use FreeBSD+PF and Juniper
> > NetScreen/SSG to do NAT66 in several different locations, and they all
> > works as expected so far.
> >
> > Some people don't like NAT especially NAT66, but to be realistic that
> > does work, and works well in terms of providing redundancy over two
> > DSL lines for office / residential needs.
> >
> > --
> > Michel~
> >
> >
> >    
> Although i generally hate NAT, multihoming must be the only (or at least 
> the most important) reason why NAT66 has to be standardized.
> Otherwise some kind of routing must be implemented on hosts.

And what's wrong with routing on hosts?  If a router advertises a
prefix it should know where to send traffic that originates from
that prefix.  You just choose the next hop by looking at which
routers are advertising the prefix for the source address for this
packet and choosing between them.  It's a touch more state to be
kept with every address.  It would also be useful for filtering out
rouge RAs.  You look at the address you learnt the prefix from then
filter out that router / prefix.

> --
> Tassos
> 
> 
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org




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