Subject: [Ipsec] "Non-initial" vs. "Initial" Fragments Definition

From: "Vishwanath Edavayyanamath" <[email-masked]>
Date: Fri, 10 Sep 2004 20:44:32 +0530

Hello,
    In the draft-ietf-ipsec-rfc2401bis-02.txt page 18 it is stated that,
 
And the phrase "initial"
       fragment is used to mean a fragment that contains all the selector
       values needed for access control. However, it should be noted that
       for IPv6, which fragment contains the Next Layer Protocol and
       ports (or ICMP message type/code or Mobility Header type) will
       depend on the kind and number of extension headers present.
       The "initial" fragment might not be the first fragment.
                                            ^^^^^^^^^^^^^^^^^^^^^^^
 
In which case this will apply? while there is a minimum packet size defined
(576 fragmented or not) and the headers in context (next layer protocol,
ports, etc) pretty much fit in the minimum packet size defined (again 576
fragmented or otherwise).
 
So, I feel the statement is redundant and can be removed.

Regards
Vishwa

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---

From: Francis Dupont <[email-masked]>
Date: Sat, 11 Sep 2004 01:41:56 +0200

In your previous mail you wrote:

   In which case this will apply?

=> when there is a large destination option header after the fragmentation
header and the end of the first fragment falls in it.

   while there is a minimum packet size defined
   (576 fragmented or not) and the headers in context (next layer protocol,
   ports, etc) pretty much fit in the minimum packet size defined (again 576
   fragmented or otherwise).

=> I can't parse your argument. The minimum fragment payload size is 8 octets,
and 576 is the minimal garanted size for reassembly of IPv4 packets
(minimal MTU is 68, in IPv6 the values are 1500 and 1280).

=> redundant? You can believe it is false (so I've given an example).

Regards

[email-masked]