Along these lines there are two other aspects that are worth
considering:
1. A single address with scope larger than link-local would indeed be
sufficient for a router as long as the network management policies and
tools do not need to reach specific interfaces for troubleshooting
purposes for example.
2. In the case of a Service Provider that offers VPN services, an
address with a scope larger than link-local is necessary for each VRF
for things such as PMTU discovery. In that case, it might be easier to
simply assign that address to the PE-CE link rather than create for
example a loopback for each VRF.
In principle link-locals are sufficient for the PE-CE link however in
practice, all little details considered, people might end up assigning
more than that to the link. And in that sense, it will be better to use
a prefix set aside by the SP for its own infrastructure rather than what
is delegated to the customer (as Ole mentioned).
Regards,
Chip
-----Original Message-----
From: owner-v6ops@ops.ietf.org [mailto:owner-v6ops@ops.ietf.org] On
Behalf Of Fred Baker (fred)
Sent: Wednesday, March 01, 2006 11:30 AM
To: Bonness, Olaf
Cc: Ole Troan (otroan); jordi.palet@consulintel.es; v6ops@ops.ietf.org
Subject: Re: AW: Guidelines for Numbering IPv6 Point-to-Point Links and
Easing the Addressing Plans
My assumption as a routing geek is that the only reasonable use of a
numbered point to point link is to address an end station; it needs an
address to be useful in the network. But any router/router point-
to-point interface should be supportable using link-local addresses.
A router needs one address reachable by its administration (eg non-
link-local), to be a member of any prefix on a LAN that it is serving,
and to be able to reach p/p-connected end stations it serves.
On Mar 1, 2006, at 5:41 AM, Bonness, Olaf wrote:
4. Routing Aggregation of the Point-to-Point Links
Following this approach and assuming that a shorter prefix is
typically delegated to a customer, in general a /48 [4], it is
possible to simplify the routing aggregation of the point-to-point
links. Towards this, the point-to-point link may be numbered
using
the first /64 of a given /48.
using the first (or any) subnet of a larger prefix, breaks the
conceptual model of DHCP prefix delegation. the prefix is delegated
to the requesting router and cannot be used to number the link
between the delegating and requesting router.
My assumption from a service provider point of view would be to use a
dedicated sub-preaefix (e.g. /48)of my own aggregate to address the
point-to-point links (e.g. /64) to the custumers (in the case I have
to do this).
cu
Olaf