Subject: RE: Reviewof"Use of /127 Prefix Length Between Routers Considered Harmful"

From: "Michel Py" <[email-masked]>
Date: Wed, 12 Jun 2002 08:50:43 -0700

>>> Alain Durand wrote:
>>> I still do not understand why this draft does not simply advocate
>>> using 2 /128.
>>
>> There is something that makes me scream at the thought of not having
>> both ends in the same subnet and/or not having a route for that
subnet.
>> Possibly some frame-relay flashback? Anyway, this sounds to me as bad
as
>> using unnumbered. B.A.D.

> This sounds like F.U.D. to me. Why do you think it is B.A.D.?

It's a matter of operational practice. Same idea as having a routable
loopback interface, for example. There are no addressing architecture
requirements that says you need a routable loopback, but lots of people
have them anyway.

Place this in context: what we are talking about here is either a
router-to-router tunnel or a router-to-router link. Guess what: there is
likely to be a routing protocol there. Could you explain me how you
configure RIP when the other router is not on the same subnet?

Michel.

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From: Brian Haberman <[email-masked]>
Date: Wed, 12 Jun 2002 22:08:16 -0400

> configure RIP when the other router is not on the same subnet?

In all of my labs where I have had p2p links like that, both
ends of the link only have link-local addresses and RIPng works
just fine.

IPv6 cloud --- RTR1 --- p2p --- RTR2 ---IPv6 cloud

Each router has a global address and a link-local address on the
cloud interfaces and link-local addresses on the p2p.  RIPng
running and reachability everywhere.

Brian