Subject: [Hipsec] proposed HIP base and ESP draft changes (UPDATE handling)

From: "Henderson, Thomas R" <[email-masked]>
Date: Tue, 17 Jan 2006 08:26:52 -0800

In the course of working on the next version of the mobility draft, I
reviewed the material regarding UPDATE message in the current base and
ESP drafts and decided that it was underspecified.  In particular, I
found the following problems:

i) the current draft allows for multiple UPDATE messages to be
outstanding (unacknowledged), but doesn't say how such messages must be
processed if they are received out of order (processed out of order,
resequenced and processed in order, etc.).  In fact, the current draft
permits multiple UPDATEs to be sent, but the receiver processing text in
Section 6.12.1 does not allow for any reordering in the network, and
such handling is undefined.

There were a few options discussed, including changing the UPDATE
protocol to be more like go-back-N ARQ, or adding new selective "NACK"
parameters or some new parameter that cancels an outstanding UPDATE if
needed, but in the end, I opted to just clarify that it is the
responsibility of the sender to only send multiple outstanding UPDATEs
under the assumption that they may be processed in any arbitrary order--
if the ordering matters to the sender, then it needs to wait for an
acknowledgement of the relevant UPDATE(s).  If needed in the future, we
can add a more sophisticated mechanism, but it doesn't seem necessary
right now for the primary uses of UPDATE.

ii) related to this, there was clarification added that the receiver may
define a receive window for UPDATE sequence numbers, rejecting those
that seem too far out of bounds based on the current value of the peer's
Update ID.  Likewise, it was clarified that circular sequence number
processing was performed on the Update ID sequence space.

iii) the draft was ambiguous as to the processing order if an UPDATE
packet had both a SEQ and an ACK parameter.  The proposed change is to
specify that the ACK is first processed, then the new material in the
UPDATE (SEQ plus whatever parameters are included).

iv) finally, there were a few clarifications also added, and typos
fixed.  One minor technical point that affects interoperability is to
change the first sent UPDATE to be numbered zero instead of one,
according to the convention of positive integers in a circular sequence
space starting with the number zero.

Before taking this proposal to the list, I discussed these proposed
changes with the draft authors and some implementors (Jan Melen, Miika
Komu, Jeff Ahrenholz).  I'm asking the list and the chairs whether these
changes are acceptable.

Tom

p.s. it is my understanding that the base draft is still awaiting
resolution of the KHI issue, and also revision of Appendix C.

Base draft proposed changes:
----------------------------
i) Context diff against current base draft:
http://hipserver.mct.phantomworks.org/ietf/drafts/draft-ietf-hip-base-04
.diff

ii) Diff of whole document in HTML (generated by Petri):
http://www.hip4inter.net/documentation/drafts/diff_04_05pre170106.html

iii) Preview of -05: 
http://www.hip4inter.net/documentation/drafts/draft-ietf-hip-base-05-pre
170106.txt

iv) Preview of -05 (XML):
http://www.hip4inter.net/documentation/drafts/draft-ietf-hip-base-05-pre
170106.xml

ESP draft proposed changes:
---------------------------
i) Context diff against current ESP draft:
http://hipserver.mct.phantomworks.org/ietf/drafts/draft-ietf-hip-esp-01.
diff

ii) Diff of whole document in HTML (generated by Petri):
http://www.hip4inter.net/documentation/drafts/diff_esp_01_02pre170106.ht
ml

iii) Preview of -02:
http://www.hip4inter.net/documentation/drafts/draft-ietf-hip-esp-02-pre1
70106.txt

iv) Preview of -02 (XML):
http://www.hip4inter.net/documentation/drafts/draft-ietf-hip-esp-02-pre1
70106.xml

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---

From: Petri Jokela <[email-masked]>
Date: Wed, 18 Jan 2006 09:22:30 +0200

> Base draft proposed changes:

Note: Appendix C, Example Checksums for HIP packets

The I1 packet is now fixed in C.1., but the C.3. is original and will be 
fixed before submission.

/petri

---

From: Pekka Nikander <[email-masked]>
Date: Thu, 19 Jan 2006 12:22:16 +0200

> Komu, Jeff Ahrenholz).  I'm asking the list and the chairs whether  

Thanks for this good work, Tom!

> resolution of the KHI issue, and also revision of Appendix C.

As far as I know, KHI is not currently making any progress.  I ran  
(temporarily) out of steam, and it seems that no-one else has picked  
it up.  I'll send private mail to the ADs and relevant WG chairs to  
see if we can make any progress.

--Pekka