IPv6 Address Planning

[Mohacsi Janos]

On Tue, 9 Aug 2005, 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.
>
> Our address allocation is 2001:1940::/32
>
> Here is our current plan, but we are looking for suggestions from people
> who have been down this road before. The plan is to break out a /48 for
> our organization. Then break out the first /64 for loopbacks, and the
> next /64 for point-to-point connections. The PTP /64 then breaks out
> further into 1 /80 for core links, and 1 /80 for each of our
> distribution sites. Within these /80's are individual /112's for PTP
> links. What this will allow us to do is aggregate each sites PTP
> connections into /80's within our IGP.
>

Another option, that used by us:
-Allocate /48 for customers
-Use /128 for loopbacks
-Use /64 where necessary to have addressable interfaces.
-Use linklocal for p2p links - even for p2p Ethernet. If there is a need 
you can add /64 later. This does not break IGP:
   - OSPFv3 uses linklocal addresses
   - IS-IS uses NSAP addresses
   However for traceroute you might have to setup for each interface "ipv6 
unnumbered loopback?" - according to Cisco terminology- to have consistent 
output.

For the aggregation use your network hierarchy. e.g. /40 for regions 
etc...

Regards,


Janos Mohacsi
Network Engineer, Research Associate
NIIF/HUNGARNET, HUNGARY
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