IPv6 Address Planning

[Joe Abley]

On 9 Aug 2005, at 14:53, Cody Lerum wrote:

> Currently we are in the process of planning our IPv6 addressing schema
> for our network. We are a service provider with around 20 core routers,
> and several hundred enterprise customers. These customers currently
> connect back to our core via a separate VLANs or channelized
> DS1/DS3/OC-X type interfaces. Thus currently lots of /30 IPv4 blocks.

In case it's useful to compare a slight variation on what you 
suggested, ISC uses the following address assignment plan. The main 
difference between this and yours is that we assign a /48 to every site 
in our network. This works for us. We like it.

[Note that ISC is not really an ISP, and would quite possibly not 
qualify for a /32 allocation from ARIN today. We were allocated 
2001:4f8::/32 before the current v6 allocation policy was adopted by 
ARIN.]

   2001:4f8:site:vlan:hhhh:oooo:ssss:tttt

We choose one 16-bit "site" value per site. The site "0000" is special, 
and is used for things like point-to-point links, /128 host routes for 
services that are not deployed in a site-specific manner, etc.

   2001:4f8:0000:0000:: (reserved)
   2001:4f8:0000:0001:: point-to-point (/112 assignments)
   2001:4f8:0000:0002:: ISC service addresses (/128 assignments)
   2001:4f8:0000:0003:: guest service addresses (/128 assignments)
   2001:4f8:0000:0004:: (reserved)
   ...
   2001:4f8:0000:ffff:: (reserved)

We number internal, ISC sites from 0001 up. We number external, guest 
sites from ffff down. If we were an ISP, we would probably use the word 
"customer" instead of "guest".

We choose one 16-bit "vlan" value per "vlan". The vlan "0000" is 
special, and is used for things like loopback /128s and other stuff 
that has no useful "vlan" number.

So, examples:

The site PAO1 (529 Bryant, Palo Alto, CA, USA) is numbered within 
2001:4f8:1::/48. The site SQL1 (950 Charter Street, Redwood City, CA, 
USA) is numbered within 2001:4f8:3::/48. The AfNOG regional operator 
meetings are assigned 2001:4f8:fffe::/48 (which is routed over a 
tunnel, when there's a meeting happening).

The service www.isc.org (which moves between hosts on occasion, and is 
hence not site-centric) is numbered 2001:4f8:0:2::d/128. The service 
ftp.isc.org (similarly) is numbered 2001:4f8:0:2::18/128.

VLAN 14 in Redwood City is numbered 2001:4f8:3:e::/64. VLAN 505 in Palo 
Alto is numbered 2001:4f8:1:1f9::/64.


Joe