[ipv6-wg] IPv6 on P2P links

On 26.05.2011 10:07, Jasper Jans wrote:
> Can anyone give me some real world experience with IPv6 numbering on P2P links in their network?
>
> I've seen the recommendations swing from '/64' to '/127 if your equipment can handle it' and even
> to 'do not assign anything at all just use link-local' and access your devices over the loopback
> which your IGP will distribute.

At my current emplyer, we are using /124 on all P2P links in our network 
(which is a multi-vendor network) with no problems. We also used /124 at 
my previous employer for this purpose. From my perspective, /124 seems 
to be pretty common for internal P2P links. We use /64 for "external" 
P2P links, i.e. facing customers or on peering links etc.

The reasoning behind /124 (rather than e.g. /127) for us, is simply to 
make addressing more "human-readable" as well as simpler to manage in 
terms of reverse DNS. Using /124 you always end up on a "human-friendly" 
boundary so your networks are xx::10/124, xx::20/124, xx::30/124 and so 
on, and you can then assign hosts that are always like xx::10:1/124 + 
xx::10:2/124 (rather than having your tech staff trying to sort out 
hexadecimal stuff in their heads). This also fits very nicely with 
nibble addressing in ip6.arpa as every network is its own "nibble". I 
believe someone wrote an I-D about using /124s a while back, but my 
memory isn't what it used to be...

Regards,
Lars Erik