Subject: LL10 applicability

From: "Philip Nye" <[email-masked]>
Date: Wed, 12 Feb 2003 10:55:57 -0000

I accept that a change needs to be made but not as worded. In general I
agree with Keith Moore's analysis:

"what we need to be saying is that due to ambiguity and stability issues
LL addresses only work well for a subset of applications; that LL cannot
be fixed to work better given the constraint that it be usable
in ad hoc networks and the shortage of IPv4 addresses; that while
some apps will work fine, other apps may or may not be able to work
around these limitations; and as such, that LL addresses should only be
used when stable, routable addresses are not available - such as on ad
hoc, isolated networks."

I suggest the following text:

---
IPv4 link-local addresses and their dynamic configuration have
profound implications upon applications which use them. This is
discussed in Section 7. Many applications fundamentally assume
addresses of communicating peers are routable, relatively
unchanging and unique. These assumptions no longer hold with IPv4
link-local addresses, therefore while many applications will work
properly with LL addresses, others may do so only after
modification, or will exhibit reduced or partial functionality, or
will fail altogether.

The design requirements for IPv4 link-local address assignment
means that they are necessarily a compromise and they should only
be used where stable, routable addresses are not available - such
as on ad hoc or isolated networks or in controlled situations
where these limitations and their impact on applications are
understood and accepted.
---

Philip