Subject: (IPng 7478) Last Call: IPv6 Jumbograms to Proposed Standard

From: The IESG <[email-masked]>
Date: Wed, 05 May 1999 08:42:41 -0400

The IESG has received a request from the IPNG Working Group to consider
IPv6 Jumbograms <draft-ietf-ipngwg-jumbograms-00.txt> as a Proposed
Standard.

The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action.  Please send any comments to the
[email-masked] or [email-masked] mailing lists by May 19, 1999.

Files can be obtained via
http://www.ietf.org/internet-drafts/draft-ietf-ipngwg-jumbograms-00.txt

--------------------------------------------------------------------
IETF IPng Working Group Mailing List
IPng Home Page:                      http://playground.sun.com/ipng
FTP archive:                      ftp://playground.sun.com/pub/ipng
Direct all administrative requests to [email-masked]
--------------------------------------------------------------------

---

From: [email-masked]
Date: Fri, 07 May 1999 15:39:10 +0900

>http://www.ietf.org/internet-drafts/draft-ietf-ipngwg-jumbograms-00.txt

	I found that it is very hard to use jumbo payload option with IPsec
	AH.  It may be good to add a notice somewhere.  (but this is
	NOT a big deal, just add one line and it should be fine - it should
	not affect the standard process, at all)

	Suppose that the policy asks for two AH, and the packet is nearly
	64K of size.

	When attaching first AH, the payload length fits in 64K.
	AH crypto checksum will be performed for the underlined part.
		IPv6 AH1 payload
		================ AH1
	Then, by adding second AH, the payload size exceeded 64K.
	We'll need to add jumbo payload option.
		IPv6 HBH(jumbo) AH2 AH1 payload
		=============================== AH2

	When the receiving node sees the packet, it will verify AH2, then
	remove AH2, modify the packet size field in jumbo payload option.
		IPv6 HBH(jumbo) AH2 AH1 payload
		=============================== AH2
			v
		IPv6 HBH(jumbo) AH1 payload
	Here, the size field in jumbo payload option will be come less than
	64K.  The packet is not trivial for receiving node to process, because:
	- it can be wrongly formatted packet by the source (a packet with
	  illegal jumbo option), so receiving node cannot simply strip off HBH
	- how to strip off HBH anyway?  what if you have other HBH options
	  on the HBH part?  padding?

	In my implementation I disallowed AH on jumbograms - it is the
	easiest solution :-P

itojun