Subject: [manet] DPD for IPv6 - fragmentation support

From: "Teco_Boot" <[email-masked]>
Date: Tue, 31 Jul 2007 10:01:14 +0200

Hi Joe,

As fragmentation with IPv4 is to be supported, IPv6 fragmentation support
can be considered too.

It even brings efficiency, as adding the DPD header is eliminated if a
fragment header was included by the source.

Draft algorithm below. I am not sure about the optional tagging *), this
depends on the --to be written-- rules for used SMF mechanisms in a MANET.

I am not a protocol implementer. But if, I would consider a single hash
table for IPv4 and IPv6 and run the hash algorithm over those fields that
guarantee uniqueness, or over the first N octets of a frame with blanked
fields TTL, TOS and hop-by-hop & routing headers. Code maintaining the table
and performing fast lookups would be shared for all types of traffic.

Teco.

+-------------+-----------------+-------------+-----------------------------
-------------+

|IPsec header | Fragment header | DPD header  | action
|

+-------------+-----------------+-------------+-----------------------------
-------------+

| present     |       *         |      *      | IPsec header DPD check and
forward       |       

| not present | present         | not present | Fragment header DPD check
and forward (1)|

| not present | present         | present     | invalid, do not forward (2)
|

| not present | not present     | not present | Optionally tag and forward
(3)           |

| not present | not present     | present     | DPD header DPD check and
forward         |

+-------------+-----------------+-------------+-----------------------------
-------------+

1: DPD check based on
<sourceAddress::destinationAddress::Identification::FragmentOffset>

2: SMF shall use fragment header if present. Adding DPD header should never
occur.

3: Received packets are sent by connected hosts or forwarded by MANET SMF
routers implementing DPD based on hashing. Tagging is optional *).

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