Introduction
------------

This piece of software is a tunnel that compresses VoIP traffic, ie. SIP and
RTP traffic.

The program is named IP/ROHC or iprohc. It is named according to the compression
and transport mechanisms it uses:
 - the program uses the RObust Header Compression (ROHC) protocol for efficient
   compression of the RTP datagrams,
 - the program uses IP packets as transport to avoid the overhead introduced by
   the UDP or TCP protocols.

In addition to ROHC commpression and IP transport, the program uses datagram
packing to improve the overall compression performances.

The IP/ROHC program is divided into two parts: the server and the client. The
server part handles sessions with several clients simultaneously.

The client and the server establish two communication channels between them: the
control channel that uses TCP for reliability, and the data channel that uses
UDP for efficiency. The client establishes and closes a session on the control
channel. The client transmits compressed data on the data channel. The control
channel is authenticated and encrypted with TLS.

Both the client and the server uses TUN interfaces to fake network interfaces.


Official website:      http://rohc-lib.org/
Mailing list:          rohc@lists.launchpad.net
Mailing list archives: http://lists.launchpad.net/rohc/
Bugtracker:            http://bugs.launchpad.net/rohc


License
-------

The project is licensed under GPL2+, see the COPYING and AUTHORS files for more
details.


References
----------

ROHC          RObust Header Compression (ROHC): Framework and four profiles:
              RTP, UDP, ESP, and uncompressed.
              http://www.ietf.org/rfc/rfc3095.txt

ROHC library  The ROHC library used by the IP/ROHC program.
              http://rohc-lib.org/