[149417] in North American Network Operators' Group
Re: IPv6 dual stacking and route tables
daemon@ATHENA.MIT.EDU (Ryan Rawdon)
Fri Feb 3 15:20:50 2012
From: Ryan Rawdon <ryan@u13.net>
In-Reply-To: <4F2C3F18.3080804@gmail.com>
Date: Fri, 3 Feb 2012 15:20:03 -0500
To: -Hammer- <bhmccie@gmail.com>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Feb 3, 2012, at 3:10 PM, -Hammer- wrote:
> So, we are preparing to add IPv6 to our multi-homed (separate routers =
and carriers with IBGP) multi-site business. Starting off with a lab of =
course. Circuits and hardware are a few months away. I'm doing the =
initial designs and having some delivery questions with the carrier(s). =
One interesting question came up. There was a thread I found (and have =
since lost) regarding what routes to accept. Currently, in IPv4, we =
accept a default route only from both carriers at both sites. Works =
fine. Optimal? No. Significantly negative impact? No. In IPv6, I have =
heard some folks say that in a multi-homed environment it is better to =
get the full IPv6 table fed into both of your edge routers. Ok. Fine. =
Then, The thread I was referring to said that it is also advisable to =
have the entire IPv4 table fed in parallel. Ok. I understand we are =
talking about completely separate protocols. So it's not a layer 3 =
issue. The reasoning was that DNS could potentially introduce some =
latency.
>=20
> "If you have a specific route to a AAAA record but a less specific =
route to an A record the potential is for the trip to take longer."
>=20
> That was the premise of the thread. I swear I googled it for 20 =
minutes to link before giving up. Anyway, can anyone who's been thru =
this provide any opinions on why or why not it is important to accept =
the full IPv6 table AND the full IPv4 table? I have the hardware to =
handle it I'm just not sure long term what the reasoning would be for or =
against. Again, I'm an end customer. Not a carrier. So my concern is (A) =
my Internet facing applications and (B) my users who eventually will =
surf IPv6.
>=20
> Any guidance would be appreciated. Thanks.
>=20
> -Hammer-
We have been accepting our upstreams' connected and customer routes only =
(v4) and full routes (v6) without issue. I can't say that I have =
previously heard of the DNS performance example/concern you provided =
above=
