Subject: Re: [Tsvwg] RFC2960bis ... heads up Steve

From: Jonathan Wood <[email-masked]>
Date: Thu, 10 May 2001 12:40:35 -0700 (PDT)

>
>But this is my confusion.. if I compose an INIT how do I know if
>you are in my site or not based on the application sending to a
>Global address... I have no way that I know of... please educate me here...
>

As far as I can tell, having just gone and looked at the v6
scoping draft, there isn't any way to tell -- site IDs are
not globally unique, so there is a chance for collision.

The main sticking point, for me, is whether or not to
send site-locals in an INIT / INIT ACK. As Jim and Randy
have pointed out, if you do include them, there is a chance
for end users to shoot themselves in the foot.

However, think we should NOT try to solve this problem in the
SCTP spec. If we do, it unneccesarily contrains the potential
uses and scenarios for SCTP. Instead, as Kacheong suggested,
we should leave this as an implementation issue, and solve
it with local policies. At most, the SCTP spec should
make a recommendation for a default policy to use.

For example, we could add a policy socket option to the
SCTP socket mapping dealing with site-locals, with the
default being to not send them.

Jonathan

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---

From: Qiaobing Xie <[email-masked]>
Date: Thu, 10 May 2001 16:50:47 -0500

Jonathan Wood wrote:
...
> make a recommendation for a default policy to use.

I agree 100% with Jonathon on this.. It's too early to make a solid
conclusion on this coping issue. The future development in IPng and
multi6 may point us to the right solution(s).

regards,
-Qiaobing

---

From: Randall Stewart <[email-masked]>
Date: Fri, 11 May 2001 13:21:41 -0500

> multi6 may point us to the right solution(s).

I have just had a long converstation with Jim Bound. We are both
in 100% agreement on this.. the guidlines that ARE in the bis that
I sent out this A.M. are essential. Lack of them will provide a
nightmare interoperability problem with site-local addresses (and
link-local addresses).

I will call Steve Deering next week when he returns from his
"out of the office" stint... I want his opinion on this as well but
Jim and I both feel he will agree with us...

The other items Jim talked about for site-local are only for slicing a
site-local within a site. The rules I laid out will work no matter
if this slicing is in effect or not... The only difference will be
that if the slicing (there is a ng draft on this something on scoping)
is in place, the sending SCTP will get a EHOSTUNREACH right away and
thus end its INIT -> sent to a erroneous site-local faster... this just
improves things...

You can NOT leave such a black hole within the protocol.. it would be
a crime that would make itself evident when IPv6 and SCTP become
fully deployed has SCTP associations fail more and more often has
site-local
addresses become used...

Bad idea... we MUST put this scoping in place...

R

-- 
Randall R. Stewart
Systems & Solutions Engineering
Cisco Systems Inc.
[email-masked] 815-342-5222 or 815-477-2127