[tg] IP fragmentation issue.
Hugues VAN PETEGHEM
hvp at info.fundp.ac.be
Thu Apr 15 06:54:56 PDT 2004
Hi,
Yes, I'm using Ethernet and I know that the IP MTU over Ethernet is 1500
bytes. But as 'tg' is in the "application layer" (above "network layer" ->
IP), IP fragmentation must be invisible for 'tg'. Isn't it ?
H
On Thursday 15 April 2004 15:50, Arthur de Castro Callado wrote:
> What network technology are you using? Ethernet?
>
> Ethernet frames must have up to 1500 bytes, no more. This limits the size
> of the packet in a way that when one wants to transmit segments with more
> than is allowed (bytes 1500 - headers), the segment will be divided into
> pieces before sending.
>
> Arthur.
>
> On Thu, 15 Apr 2004, Hugues VAN PETEGHEM wrote:
> > Hi all,
> >
> > I got an IP fragmentation problem using 'tg'. Here is the problem
> > statement :
> >
> > --------- ---------
> >
> > | pc10 |--------------------------------| pc6 |
> >
> > ---------10.0.0.10 10.0.2.2--------
> >
> > I'm trying to generate a simple data flow from pc10 (10.0.0.10) to pc6
> > (10.0.2.2). Here are the 'tg' input files :
> >
> > # pc10
> > on 0:15 tcp 10.0.2.2.80
> > at 5 setup
> > at 6 arrival 0.5 length 2000
> > packet 300
> >
> > # pc6
> > on 0:15 tcp 0.0.0.0.80 server
> > at 1 wait
> >
> > After a couple of minutes, I use 'dcat' to transform the log files in
> > text files and here are the first lines of both files :
> >
> > # pc10
> > (...)
> > Event Time Type Address Id Length
> > -----------------------------------------------------------------
> >
> > 5.010170 Setup
> > 6.509204 Transmit 10.0.2.2.80 0 2000
> > 7.009049 Transmit 10.0.2.2.80 2000 2000
> > 7.508948 Transmit 10.0.2.2.80 4000 2000
> > 8.008956 Transmit 10.0.2.2.80 6000 2000
> > (...)
> >
> > >From the client side, everything goes perfectly. Each packet is sent to
> >
> > 10.0.2.2:80 every 0.5 second. These packet have a 2000 bytes length.
> >
> > # pc6
> > (...)
> > Event Time Type Address Id Length
> > -----------------------------------------------------------------
> >
> > 0.004769 Setup
> > 19.742468 Accept 10.0.0.10.1207 Association 5
> > 21.238312 Receive 10.0.0.10.1207 0 2000
> > 21.737539 Receive 10.0.0.10.1207 2000 1448
> > 21.737888 Receive 10.0.0.10.1207 3448 552
> > 22.237457 Receive 10.0.0.10.1207 4000 1448
> > 22.237830 Receive 10.0.0.10.1207 5448 552
> > (...)
> >
> > >From the server side, the first packet is well received, but after that,
> >
> > everyhing is "wrong". I mean, it receive the data, but fragmented.
> >
> > I think it is a 'tg' (or 'dcat') problem. Have someone faced this before
> > ? If not, could you try it and tell me if you have the same problem.
> >
> > Thanking you in advance :
> >
> > H
> > --
> > Hugues VAN PETEGHEM
> > Institut d'Informatique - FUNDP
> > ---------------------------------------------
> > Web : http://www.info.fundp.ac.be/~hvp/
> > _______________________________________________
> > tg mailing list
> > tg at postel.org
> > http://www.postel.org/mailman/listinfo/tg
--
Hugues VAN PETEGHEM
Institut d'Informatique - FUNDP
---------------------------------------------
Web : http://www.info.fundp.ac.be/~hvp/
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