[137082] in North American Network Operators' Group
Re: IPv6 addressing for core network
daemon@ATHENA.MIT.EDU (Sam Stickland)
Wed Feb 9 08:35:10 2011
In-Reply-To: <20110209.104804.74661138.sthaug@nethelp.no>
From: Sam Stickland <sam@spacething.org>
Date: Wed, 9 Feb 2011 13:35:03 +0000
To: "sthaug@nethelp.no" <sthaug@nethelp.no>
Cc: "vikassharmas@gmail.com" <vikassharmas@gmail.com>,
"nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On 9 Feb 2011, at 09:48, sthaug@nethelp.no wrote:
>> Is there a NANOG FAQ we can add this to?
>>=20
>>> 1- Use Public Ipv6 with /122 and do not advertise to Internet
>>> 2- Use Public Ipv6 with /127 and do not advertise to Internet
>>=20
>> The all zeros address is the all routers anycast address so on most non-C=
isco routers you can't use it, ruling out /127. The top 128 addresses in any=
subnet are also reserved anycast addresses although they don't do much in p=
ractice. So the longest prefix length you should use is /120 and only use ad=
dresses 1 - 127.
>=20
> A /127 mask is still the best way to handle real point-to-point links
> like SDH/SONET today, to avoid the ping-pong problem. Works fine with
> Cisco and Juniper, not tried with other vendors.
>=20
Can you elaborate on this? What's the ping-pong problem?=20
Sam (who's experience is pretty much mostly ethernet)=
