University of Essen / Institute for Experimental Mathematics / Computer Networking Technology Group / Thomas Dreibholz

RTP Audio
Realtime Audio Transport with QoS Management in a DiffServ Scenario

Zur deutschen Version dieses Dokumentes

Description

• RTP Audio
  The RTP Audio System contains a server and several clients, which are served with audio data from the server. The transmission is realized using the RTP protocol (Real-Time Protocol, see RFC 1889) based on UDP. RTP Audio supports IPv4 and IPv6 including flowlabels and traffic classes. Three versions of clients are available: A shell version, a version using the Qt GUI and a Java version using Swing.
  The RTP Audio Server control is realized using RTCP messages. This includes login/logout, quality and position changes, and feedbacks of the clients to the server. The server reads audio files grouped to audio lists. Audio lists may contain WAV and MP3 files. MP3 files are decompressed by the server using libmpegsound.
  For audio transmission, two encodings habe been developed: Simple Audio Encoding and Advanced Audio Encoding. The last one splits the stream into 1, 2 or 3 layers having descending priorities and may therefore have different DiffServ classes and probability of packet loss. It is now possible to do an error correction by replacing missing data of one audio channel by the data of the other channel. The IP packets are marked with IPv4 TOS/IPv6 Traffic Class byte given by the QoS management to support DiffServ usage. Using IPv6, flowlabels are also used to support bandwidth reservation.

• Measurement Tools
  For network bandwidth measurement and the evaluation of the developed system, measurement tools have been developed: netlogger records aggregated traffic statistics using libpcap, netanalyzer generates GNUplot output from the recordings. rttp does round trip time measurements using ICMP.

• Quality of Service Management
  RTP Audio provides QoS requirements to the QoS manager of Simon Vey and the reservation module of Jan Selzer. The QoS manager returns bandwidth and traffic classes for the stream's layers.

News

• 26-Nov-99 RTP Audio project started.
• 29-Sep-00 WWW pages translated into English language.
• 11-Oct-00 Update of programs and documentation.
• 26-Nov-00 Update of programs and documentation. Today is RTP Audio's first anniversary.
• 29-Dec-00 Update with bugfix for RTCP sender reports.
• 23-Feb-01 Update of implementation and documentation.
• 24-Feb-01 PDF version of documentation available.
• 01-Dec-11 RTP Audio is continued in the RTP Audio NextGen project!
• 20-Apr-12 Reformatted PDF version of the documentation, including PDF bookmarks, is available.

Documentation of Server and Clients

• List of all files
• List of all globals
• Class hierarchy

Documentation of the Java Client

• Click here to go to the Java Client's documentation!

RTP Audio Papers

• Updated detailed description and documentation (4.3 MiB, PDF)
• Old version (2.3 MiB, PDF)
• Old version (3.2 MiB, PostScript/GZip)

Screenshots and UML Diagrams

• Click here to go to the screenshots and UML diagrams!

Download

• Download RTP Audio, Tar/GZip
• View installation manual

Useful Links

• Vorlesung Rechnernetze I
• Vorlesung Rechnernetze II
• Argo UML 0.70
• IBM XML4J (required for Argo UML)

20.04.2012 Thomas Dreibholz, University of Essen / Institute for Experimental Mathematics / Computer Networking Technology Group