Subject: RE: New version of draft-wbeebee-nd-implementation-pitfalls is available - 2nd try

From: "Hemant Singh (shemant)" <[email-masked]>
Date: Fri, 10 Aug 2007 15:14:54 -0400

IETF IPv6 Community,
 
Please review the -02 version of our I-D. In particular, we'd like
reviewers to focus on our proposed changes to 2461bis.
 
We would like to specify on-link vs. off-link determination more clearly
for ALL IPv6 hosts.  On-link vs. off-link determines data forwarding and
address resolution behavior for a host.
 
We present a very important problem that relates to an aggregator router
network used in deployments listed below (thanks to Adeel Ahmed for
providing the list):
 
- Wholesale Dial / Voice
- DSL / ETTH / WLAN
    - Point-to-Point Model
    - PPP Terminated Aggregation (PTA) Model
    - L2TP Access Aggregation (LAA) Model
 
In the U.S. alone, these aggregation router deployments span more than
50 million household subscribers - translating to at least 50 million
potential IPv6 hosts in the future.
 
First paragraph of section 3.1 of our I-D clearly explains why a routed
aggregator doesn't echo packets received on any upstream down the
downstream that corresponds to the upstream. The paragraph also explains
how hosts in such an aggregation router deployment do not directly
communicate to each other - hosts have to send traffic through the
aggregation router. This deployment connectivity topology is known as
off-link operation.  Thus, an aggregation router deployment MUST specify
that hosts even in the same prefix are off-link in the RA from the
aggregation router. 
 
In some cases, on-link behavior can be clearly determined as specified
in 2461bis.  Off-link is defined as the opposite of on-link.  In order
to be sure that a host is operating in off-link mode,
ALL cases in which a host should be on-link need to be clearly specified
- thus, defining on-link and off-link mode clearly.
 
Given the fact that an aggregation router deployment needs to ALWAYS
specify off-link mode to hosts behind modems, the RA with "no PIO" case
is potentially relevant to a large number of subscribers in an IPv6
aggregation router deployment. 
 
-Hemant & Wes.

________________________________

From: Hemant Singh (shemant) 
Sent: Monday, July 23, 2007 5:31 PM
To: [email-masked]
Cc: [email-masked]; Hemant Singh (shemant); Wes Beebee (wbeebee)
Subject: New version of draft-wbeebee-nd-implementation-pitfalls is
available

Folks,
 
Please see a new version of our I-D at the URL below. 
 
http://www.ietf.org/internet-drafts/draft-wbeebee-nd-implementation-pitf
alls-02.txt
 
See change log to understand what has changed from the -01 version.
Gross changes worth highlighting are:
 
1. A new section 7 has been added to the I-D that lists IPv6 ND
implementation problems ala RFC 2525.
2. Section 5 is complete that lists proposed changes to 24621bis.
3. Section 6 has been edited and augmented for proposed changes to
2462bis.
 
Best Regards.
 
Hemant
--------------------------------------------------------------------
IETF IPv6 working group mailing list
[email-masked]
Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6
--------------------------------------------------------------------