HP-UX Multimedia Streaming Protocols

hp-ux multimedia streaming protocols white paper

December 2004

protocol overview

Real Time Protocol (RTP)

Real Time Protocol (RTP) is a transport protocol that provides end-to-end

network transport functions for applications transmitting data with real-time

properties, such as interactive audio and video. These services include payload

type identification; sequence numbering; time stamping and delivery

monitoring. Applications run RTP on top of UDP.

RTP consists of Real-Time Control Protocol (RTCP), a closely linked protocol,

which provides a mechanism for reporting feedback on the transmitted real-

time data.

RTP can be used in the following scenarios:

 Multicast audio conference

 Audio and video conference

 Mixers and translators

Real Time Streaming Protocol (RTSP)

Real Time Streaming Protocol (RTSP) controls the transfer of real-time media

data and serves as a network-remote-control for multimedia services. The client

requests a selected media file from the server using RTSP. The server, in

response, returns information required by the client to transfer the media data.

Applications, which use HP-UX MSP libraries, run RTSP on top of TCP.

Session Description Protocol (SDP)

Session Description Protocol (SDP) describes the general real-time multimedia

sessions. A multimedia client uses SDP to announce a conference session by

periodically multicasting an announcement packet to a familiar multicast

address and port using Session Announcement Protocol (SAP).

SDP conveys information about media streams in multimedia sessions and

allows the recipients of a session description to participate in the session. The

primary use of SDP is in an Internetwork, but it is sufficiently general that it can

describe multimedia conferences in other network environments.

msp on hp-ux

The MSP framework for HP-UX multimedia streaming servers includes libraries

required for implementing the multimedia streaming protocols (RTP, RTSP, and

SDP) and transmitting real-time data over remote networks. These libraries use

underlying transport mechanisms, such as TCP and UDP, to deliver multimedia-

streaming services.

The MSP implementation on HP-UX offers greater benefits in terms of high

performance, ability to take advantage of scalability, reliability, and high

availability of the HP-UX operating system.

MSP is available as a web release on the HP-UX 11i v1 and HP-UX 11i v2

operating systems.

library features

The following lists the features that the MSP libraries support:

RTP/RTCP

 Payload identification

 Sequence numbering