Re: RFC 3178 mh (was Re: I-D ACTION:draft-huston-multi6-architectures-00.txt)

[Pekka Savola <pekkas@netcore.fi>]

On Mon, 24 May 2004, marcelo bagnulo braun wrote:
> El 20/05/2004, a las 10:21, Pekka Savola escribió:
> >
> [...]
> >                                      However, this draft does not
> >          address another major drawback of the RFC 3178 approach, that
> >          it does not protect against the complete failure of one or 
> > more
> >          connected ISPs.
> >
> > ==> I think this is something where one should make a reality check.
> > How often is it that the _whole_ ISP fails?  Pretty much _never_,
> 
> IMHO the problem is that RFC 3178 multihoming situation not only fails 
> when the complete ISP fails, but it also fails when
> - one of the access routers of the ISPs fail,
> - one of the exit routers of the site fail
> - one of the links between the ISPs and their upstream provider fail
> 
> While i agree that probably the complete failure of the ISP may be a 
> low probability event, i guess that the above mentioned events may be 
> more common.

No, this is definitely not the case.  The first two bullet points are
only valid if site site does not have tunnels to from the other exit
routers to the other ISPs (or the tunnel is terminated at the ISP to
the same router as the physical link), right?  The third point is only
valid if the ISP has only one link to an upstream provider -- and no
self-respecting ISP has only one upstream link.
 
> The other reality check that i would like to do is how common is RFC 
> 3178? if it is not very common, what do you think are the reasons for 
> its non adoption?

True enough.  I don't think there is sufficient evidence to make
conclusions of this, as the number of v6-enabled enterprises which
don't have IPv6 /32 prefixes (but which multihome w/ v4) is very
low..?

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings