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

>>
>> 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?

Well, this is possible but this is not described in RFC 3178 and it 
imposes additional configuration, for instance of the IGP of the ISP. 
But i agree that it is possible to support this configuration, with 
some added complexity. My point was aimed to identify another possible 
cause for the non success of this solution, which could be related to 
operational complexity? I mean, tunnel management, and added features 
like the support for additional failure modes may require additional 
manual configuration, which may make the solution less attractive.


> 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.
>

Well, you are assuming that very small sites will obtain its own 
address block from the RIR, which may not hold, i guess


>> 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..?


Well, i guess this is an important issue to understand, since if rfc 
3178 multihoming is enough for some small sites (for instance), the new 
solution should be focused to satisfy the needs of the remaining sites 
(medium/big) sites, and the scalability required may be different.

In other words, understanding the reasons why rfc 3178 is not a good 
option may provide us good information for the design of the new 
solution, especially w.r.t to deployability.

regards, marcelo

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