[Michael Tuexen <Michael.Tuexen@xxxxxxxxxxxxxxxxx>]

On Feb 13, 2007, at 6:15 PM, Luis Ontanon wrote:

> I have a further question:
>
> Can the PMTU of the smallest path of an association shrink between the
> transmission of a bundled packet and its retransmission forcing the
> sender to retransmit the various chunks of a message in more messages?
Sure. And on retransmissions the packets are built depending on what
was received by the peer, so the packet can look different.
> i.e. : Can I just track the highest TSN in a packet and look for its
> ack, or should I track every data chunk of each packet separatelly?
No, you have to track each TSN. Have a look at the packet-sctp.c
reassembly code and also at the GUI stuff in gtk/ subdirs, where
also all associations are tracked.
> Thanks Again,
> Luis
>
> On 2/13/07, Michael Tuexen <Michael.Tuexen@xxxxxxxxxxxxxxxxx> wrote:
> > Hi Luis,
> >
> > see my comments in-line.
> >
> > Best regards
> > Michael
> >
> > On Feb 13, 2007, at 2:14 PM, Luis Ontanon wrote:
> >
> > > I need to implement the identification of retransmitted packets and
> > > calculation of RTT to the sctp dissector.
> > >
> > > - Is someone already working on this?
> > I recently committed code for SCTP reassembly. Please have a look  
> > at it.
> > It should be easy to add retransmission detection to it. Just look  
> > for
> > the TSN of the DATA chunks. The (half associations) are detected by
> > the port numbers and the V-tag.
> > > - other than RFC 2960  (sec. 6.3) what other rfcs I must read in  
> > > order
> > > to implement these?
> > Should be OK.
> > > - are there any caveats I must be aware before starting this  
> > > venture?
> > For RTT detection you have to "connect" both directions of the
> > association.
> > Since you can not really use the source/destination address you  
> > have to
> > use a heuristic to combine both half directions.
> >
> > Please let me know if you have further questions.
> > > Thanks,
> > >
> > > Luis
> > >
> > > --
> > > This information is top security. When you have read it, destroy
> > > yourself.
> > > -- Marshall McLuhan
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>
> --
> This information is top security. When you have read it, destroy  
> yourself.
> -- Marshall McLuhan
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