[rohc] ROHC-FN and TCP Profile - Version 3

["Price, Richard" <richard.price@roke.co.uk>]

Hi Yousuf and others,

We've updated our implementation to print out a list of the
TCP/IP packet formats. A copy is available at:

http://sigcomp.srmr.co.uk/~rjp/ROHC-FN_Version_3.zip

Just type "build(n)." where n = 0, 1 or 2 depending on how much
information you'd like to be displayed:

n = 0: Prints the 'core' packet formats only, excluding any fields
       compressed using list encoding (such as the TCP options).
n = 1: Prints the packet formats in full, including any fields
       compressed using list encoding.
n = 2: Prints all packet formats. If a variable-length compressed
       field is encountered, the formula for calculating its length
       is also displayed.

The results are saved in the file "output.txt" for later reference.

As an example, Packet Format 0 (the simplest one) is as follows:

Packet Format 0:

   discriminator:        00
   header_crc:           3 bits
   master_seq_number:    2 bits
   tcp_psh_flag:         1 bit
   tcp_checksum:         16 bits

Let me know if you have any suggestions for improvements!

Regards,

Richard

> -----Original Message-----
> From: Yousuf.Saifullah@nokia.com [mailto:Yousuf.Saifullah@nokia.com]
> Sent: Tuesday, April 29, 2003 9:43 PM
> To: Price, Richard; rohc@ietf.org
> Subject: RE: [rohc] ROHC-FN and TCP Profile - Version 2
> 
> 
> Hi Richard,
> I think it would be useful to have the pictorial format generation. 
> 
> Thanks,
> Yousuf
> 
> -----Original Message-----
> From: ext Price, Richard [mailto:richard.price@roke.co.uk]
> Sent: Tuesday, April 29, 2003 9:51 AM
> To: Saifullah Yousuf (NRC/Dallas); rohc@ietf.org
> Subject: RE: [rohc] ROHC-FN and TCP Profile - Version 2
> 
> 
> Hi Yousuf,
> 
> Drawing the Version 2 packet formats out pictorially might
> be a bit of a challenge, as they're a *lot* more complex
> than the Version 1 formats. They're now roughly as
> complicated as the packet formats in RFC 3095, so the
> pictorial form plus accompanying text will be around 100
> pages long  - a non-trivial amount of effort to generate
> by hand ;-)
> 
> A possible solution would be to modify our implementation
> so that it can automatically convert a ROHC-FN description
> of the packet formats into a pictorial one. If you think
> this feature would be useful, let me know so that we can
> add it to the next version of the implementation.
> 
> Regards,
> 
> Richard
> 
> > -----Original Message-----
> > From: Yousuf.Saifullah@nokia.com [mailto:Yousuf.Saifullah@nokia.com]
> > Sent: Friday, April 25, 2003 6:07 PM
> > To: Price, Richard; rohc@ietf.org
> > Subject: RE: [rohc] ROHC-FN and TCP Profile - Version 2
> > 
> > 
> > Hi Richard,
> > Could you please share the version 2 for the TCP compression 
> > profile in the pictorial form with textual description 
> > (basically, in the I-D format). Something similar you did for 
> > the previous version.
> > 
> > Thanks,
> > Yousuf
> > 
> > -----Original Message-----
> > From: ext Price, Richard [mailto:richard.price@roke.co.uk]
> > Sent: Wednesday, April 23, 2003 6:49 AM
> > To: 'rohc@ietf.org'
> > Subject: [rohc] ROHC-FN and TCP Profile - Version 2
> > 
> > 
> > Hi,
> > 
> > Now that Easter's out of the way, it might be a good
> > time to restart the discussion on ROHC-FN and the TCP
> > compression profile. In the interests of getting the
> > discussion going, here's a link to Version 2 of our
> > implementation:
> > 
> > http://sigcomp.srmr.co.uk/~rjp/ROHC-FN_Version_2.zip
> > 
> > For the updated implementation we've added all of the
> > encoding methods not supported in Version 1, including
> > Huffman-based discriminator encoding (i.e. EPIC-lite)
> > as well as "list" encoding for the TCP options and
> > the IP extension headers. We've also added support for
> > real IR packets with the correct indicator bits.
> > 
> > The TCP packet formats have been updated to take
> > advantage of the new encoding methods - we can now
> > compress various TCP options using list encoding, and
> > have a single discriminator for the header as a whole.
> > Minimum compressed header size is now 3 bytes.
> > 
> > One other issue - the updated implementation is
> > written in a different language from the original
> > (namely Prolog rather than Haskell). We're still
> > working on the Haskell code, but we're turning it into
> > a "proper" implementation (with full debugging and a
> > nice user interface).
> > 
> > A suitable Prolog interpreter can be downloaded from:
> > 
> > http://www.swi-prolog.org/download.html
> > 
> > For simplicity, the implementation is provided as a
> > single Prolog source file. Just open it and type
> > "comp_list(tcp_test_n)." where n is the TCP test flow
> > to be compressed.
> > 
> > Regards,
> > 
> > Richard
> > _______________________________________________
> > Rohc mailing list
> > Rohc@ietf.org
> > https://www1.ietf.org/mailman/listinfo/rohc
> > 
> 
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