Re: [IPsec] draft-smyslov-ipsecme-ikev2-fragmentation-00 fragmentation size question

[Valery Smyslov <[e-mail]>]

Hi, Paul,

thank you for reading the draft.

> I have a question about
>
> http://tools.ietf.org/html/draft-smyslov-ipsecme-ikev2-fragmentation-00#section-2.5.1
>
> It states:
>
> 2.5.1. Fragment size
>
>
>    When breaking content of Encrypted Payload down into parts sender
>    SHOULD chose size of those parts so, that resulting message sizes not
>    exceed fragmentation threshold - be small enough to avoid IP
>    fragmentation.
>
>    If sender has some knowledge about PMTU size it MAY use it.
>    Otherwise for messages to be sent over IPv6 it is RECOMMENDED to use
>    value 1280 bytes as a maximum message size ([RFC2460]).  For messages
>    to be sent over IPv4 it is RECOMENDED to use value 576 bytes as a
>    maximum message size.
>
>
> What is "message size" here referring to? The fragmentation payload, or
> the total packet length?
>
> That is, is it recommended that the packet size is 576/1280 including
> the full IP header and ISAKMP header, or that the packet size is
> 576/1280 plus the IP header and ISAKMP header?


The total IP packet length (including IP header, UDP header, IKE header).

> (and can the text in the next draft be clarified to indicate this
> better?)

Sorry for being not very precise. I'll try to clarify it in the next 
version.

> Paul

Regards,
Valery.