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Re: V6ops: IPv6 site multihoming best practices





On Fri, 16 Dec 2005, Pekka Savola wrote:


On Fri, 16 Dec 2005, Brian E Carpenter wrote:

Dwight, here is a sequence of discussion from old multi6 list.
As you can see, it isn't clear that 3178 really meets all
needs.


Brian, I think the two important needs we should see from that discussion:
1) "RFC 3178 might be too complex to set up or use" (operational complexity of tunnels, tunnel overhead, etc.)
In my opinion setting up a tunnel not so complex. It is fact of life in IPv6 Internet (and also in VPNs). The overhead and management of tunnels is not very good, however RFC 3178 is an attractive solution: You allocated prefix (e.g. /48) is "virtually provider independent" until your allocating ISP is in business and has an IPv4 connectivity with your other Internet providers.
And also gives time to shim6 to be deployed which requires signifact changes in operating systems...... 

Janos Mohacsi
Network Engineer, Research Associate
NIIF/HUNGARNET, HUNGARY
Key 00F9AF98: 8645 1312 D249 471B DBAE  21A2 9F52 0D1F 00F9 AF98




2) folks want independence, i.e., PI addresses
Shim6 doesn't meet the need 2) either, while it may help a bit with 1). I don't know if 1) would be too big of a hurdle if folks didn't need to consider 2). 


-------- Original Message --------
Subject: RFC 3178 mh (was Re: I-D ACTION:draft-huston-multi6-architectures-00.txt) 
Date: Mon, 24 May 2004 11:38:06 +0200
From: marcelo bagnulo braun <marcelo@it.uc3m.es>
To: Pekka Savola <pekkas@netcore.fi>
CC: Multi6 List <multi6@ops.ietf.org>
References: <Pine.LNX.4.44.0405201049520.1330-100000@netcore.fi>

Hi Pekka,

A couple of questions about RFC 3178 multihoming...

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.

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?

Regards, marcelo



unless you count 1-man small ISPs which don't even have redundant
connectivity and routers (and we shouldn't care about this).


-------- Original Message --------
Subject: Re: RFC 3178 mh (was Re: I-D ACTION:draft-huston-multi6-architectures-00.txt) 
Date: Mon, 24 May 2004 12:45:32 +0300 (EEST)
From: Pekka Savola <pekkas@netcore.fi>
To: marcelo bagnulo braun <marcelo@it.uc3m.es>
CC: Multi6 List <multi6@ops.ietf.org>

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