Subject: [RRG] Subnetwork Encapsulation and Adaptation Layer (SEAL)

From: "Templin, Fred L" <[email-masked]>
Date: Mon, 11 Feb 2008 16:15:47 -0800

Attached please find a new draft that proposes a
"Subnetwork Encapsulation and Adaptation Layer (SEAL)".
This work goes a step beyond the sprite-mtu proposal, and
addresses the tunnel MTU determination and duplicate packet
detection problem spaces such as required for LISP, MANET,
etc. But, it also draws on some profound concepts that
were first proposed by others many years ago. (Please see
Appendix A for an historical account and correct anything
I may have mis-characterized.)

>From a bigger picture, the proposal provides a generalized
abstraction for the carriage of IP over any subnetwork that
connects routers, e.g., Mobile Ad-hoc Networks, enterprise
networks, the interdomain routing core, etc. The proposal
is particularly applicable for subnetworks that include
links with diverse MTUs and L2 address formats, as well
as for subnetworks that may incur packet duplication due
to temporal routing loops, flooding, etc.

Please review and provide comments,

Fred
[email-masked]

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] 
Sent: Monday, February 11, 2008 3:30 PM
To: [email-masked]
Subject: I-D Action:draft-templin-seal-00.txt 

A New Internet-Draft is available from the on-line Internet-Drafts
directories.

	Title           : Subnetwork Encapsulation and Adaptation Layer
	Author(s)       : F. Templin
	Filename        : draft-templin-seal-00.txt
	Pages           : 18
	Date            : 2008-02-11

Subnetworks connect routers within a bounded region, and may also
connect to other networks including the Internet.  These routers
forward unicast and multicast packets over paths that span multiple
IP- and/or sub-IP layer forwarding hops which may configure diverse
Maximum Transmission Units (MTUs) and introduce packet duplication.
This document specifies a Subnetwork Encapsulation and Adaptation
Layer (SEAL) that supports simplified duplicate packet detection and
accommodates links with diverse MTUs.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-templin-seal-00.txt

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From: "Templin, Fred L" <[email-masked]>
Date: Tue, 12 Feb 2008 17:07:00 -0800

An update to this document has been posted:

http://www.ietf.org/internet-drafts/draft-templin-seal-01.txt

Please use this version as the basis for further
review and discussion.

Fred

> From: Templin, Fred L 
> Sent: Monday, February 11, 2008 4:16 PM
> To: [email-masked]
> Subject: [RRG] Subnetwork Encapsulation and Adaptation Layer (SEAL)
> 

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From: "Templin, Fred L" <[email-masked]>
Date: Wed, 13 Feb 2008 11:05:15 -0800

The SEAL document has been updated again; this will be
the final version leading up to IETF71:

  http://www.ietf.org/internet-drafts/draft-templin-seal-02.txt

SEAL in part specifies an MTU determination scheme based
on the Report Fragmentation (RF) concept that was first
proposed by Charles Lynn on the tcp-ip mailing list in
1987 and re-introduced by Steve Deering on the Path MTU
working group mailing list in 1989. Digests from those
lists are found at:

  http://ipvlx.com/tcp_ip.txt
  http://gatekeeper.dec.com/pub/DEC/WRL/mogul/mtudwg-log

Based on the list discussions, the Report Fragmentation
(RF) method seemed to be the most attractive approach
under consideration for IPv4 path MTU discovery, but was
abandoned in favor of the (Don't Fragment/Fragmentation
Needed) method that eventually became RFC1191. The RF
method seems to have been abandoned due in part to
difficulty in procuring an "RF" bit in the IPv4 header,
difficulty in defining an ICMP Fragmentation Report
message and the concern that not all hosts at that time
correctly implemented IP reassembly.

The SEAL proposal addresses all of these points (as well
as others) and shows that a Report Fragmentation-based
path MTU discovery capability for the Internet is still
possible and could correct the operational difficulties
associated with RFC1191 path MTU discovery. Moreover, the
SEAL approach supports true diversity, especially for
subnetworks that contain heterogeneous link types with
diverse MTUs and/or L2 address formats.

Please review and comment,

Fred

> Sent: Tuesday, February 12, 2008 5:07 PM
> To: [email-masked]
> Subject: RE: [RRG] Subnetwork Encapsulation and Adaptation 
> Layer (SEAL)
> 
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