hp-ux networking
December 2004
hp-ux multimedia streaming protocols
technical
white paper
By: Gururaj B S, CSIL Information Engineering
table of contents
introduction 2
market forecast 2
executive summary 2
problem statement 3
technology strategy 3
msp description 3
protocol overview 4
msp on hp-ux 4
library features 4
conformance to RFCs 6
Product architecture 6
deployment scenario 7
compatibility/ interoperability 7
software availability 7
glossary 8
additional information 8
1
hp-ux multimedia streaming protocols white paper
December 2004
Legal Notices
The information in this document is subject to change without notice.
Hewlett-Packard makes no warranty of any kind with regard to this manual, including, but not limited to, the implied warranties of
merchantability and fitness for a particular purpose. Hewlett-Packard shall not be held liable for errors contained herein or direct, indirect,
special, incidental or consequential damages in connection with the furnishing, performance, or use of this material.
Warranty
A copy of the specific warranty terms applicable to your Hewlett- Packard product and replacement parts can be obtained from your
local Sales and Service Office.
Restricted Rights Legend
Use, duplication or disclosure by the U.S. Government is subject to restrictions as set forth in subparagraph (c) (1) (ii) of the Rights in
Technical Data and Computer Software clause at DFARS 252.227-7013 for DOD agencies, and subparagraphs (c) (1) and (c) (2) of the
Commercial Computer Software Restricted Rights clause at FAR 52.227-19 for other agencies.
HEWLETT-PACKARD DEVELOPMENT COMPANY L.P.
20555 S.H. 249
Houston, Texas 77070
Use of this document and any supporting software media supplied for this pack is restricted to this product only. Additional copies of the
programs may be made for security and back-up purposes only. Resale of the programs, in their present form or with alterations, is expressly
prohibited.
Copyright Notice
Copyright © 2004 Hewlett-Packard Development Company L.P. All rights reserved.
Reproduction, adaptation, or translation of this document without prior written permission is prohibited, except as allowed under the
copyright laws.
2
hp-ux multimedia streaming protocols white paper
introduction
market forecast
Digital-video transmission has managed to creep into our lives. It is expected
that within the next few years, high-quality video will be distributed along with
voice and data, in our offices, and homes.
A multimedia-streaming server helps to achieve controlled streaming of
multimedia information over an enterprise network. The streaming server can
receive data from various sources, including its own secondary storage. It
consists of codecs to transform data, a mechanism to control the flow of data,
and a mechanism to deliver this data over the network.
Network enterprises find the use of streaming in delivering corporate
communications very compelling due to cost savings in applications like on-site
training, remote sales presentation, management broadcasts, etcetera.
Steve Balmer of Microsoft says, “There will be a day, I promise you, when every
corporation will view it as a routine to communicate with its employees via
streaming over the corporate intranet.”
networking computing e-mail poll, respondents were asked if they were
In a
considering using broadcast video.
Following is the result of this poll in percentile:
Answer Response (in percentage)
Yes, we are currently using it. 25
Yes, within six months. 12
Yes, in 12 to 24 months. 13
Yes, beyond 24 months. 24
The poll results indicate that companies are showing precipitous interest to use
video-broadcast, with potential opportunities in streaming products.
Internet Traffic is expected to augment from 1 Million terabytes/month to 16M
terabytes/month in the near future.
It is estimated that streaming server market will grow considerably from 64,000
units in 2001 to 212,000 in the next couple of years, approximately 300%
increase (from Video Streaming Study by Anderson school at UCLA).
HP offers an optimum framework for multimedia streaming solutions in terms of
performance as it has implemented the critical portion of RTP in the kernel. This
is HP’s key differentiating factor in the multimedia streaming market.
executive summary
This white paper presents a birds-eye-view of MSP, multimedia streaming
protocols, supported on the HP-UX 11i v1 and HP-UX 11i v2 operating systems.
It provides information about the marketing opportunities that multimediastreaming solutions provide. In addition, the document delineates the
technology strategy, HP’s offering, software availability, and so forth.
In the subsequent sections, this white paper provides an overview of MSP
protocols, scenarios in which it is used, product architecture, etcetera.
2
hp-ux multimedia streaming protocols white paper
December 2004
Problem statement
The need for a multimedia streaming solution, which facilitates faster
communication, resulted in the development of MSP. A marketing survey was
conducted by HP to analyze how customers might use MSP, and most of the
respondents seemed to be concerned with faster modes of transferring
multimedia data over remote networks.
The following chart depicts how Fortune 500 executives graded the benefits of
streaming video for corporate use:
technology strategy
Msp description
To achieve significant performance improvement, Real Time Protocol (RTP) and
Real Time Control Protocol (RTCP) have been provided in the kernel.
HP sees its MSP solution as being an Internet pervasive computing paradigm. To
provide the best MSP framework in the industry, it plans to provide streaming
accelerator, which analyzes the RTSP messages exchanged between the userspace streaming server and the client.
Multimedia Streaming Protocols (MSP) suite of protocols facilitates transfer of
audio, video and animation files to a remote location in real time. Streaming
multimedia data is a transaction between the server and the client. The client is
a user application that accesses the media, such as Real Player or Winamp.
The server is an application that provides all the client applications with the
multimedia content. Unlike the download and play mechanism, the multimedia
streaming client starts playing the media packets as soon as they arrive, without
holding back to receive the entire file. While this technology reduces the
client’s storage requirements and start-up time for the media to be played, it
introduces a strict timing relationship between the server and the client.
MSP defines the transaction that is used to establish a connection and transmit
the media from the server and client. Multimedia streaming servers use a suite
of protocols, such as the following:
Real Time Protocol (RTP)
Real Time Streaming Protocol (RTSP)
Session Description Protocol (SDP)
3
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 realtime 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.
msp on hp-ux
library features
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.
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 multimediastreaming 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.
The following lists the features that the MSP libraries support:
RTP/RTCP
Payload identification
Sequence numbering
4
hp-ux multimedia streaming protocols white paper
Time stamping
Delivery monitoring
RTSP
Establishing and terminating an RTSP connection
Sending and receiving request and response messages
Attaching headers with messages
Parsing of messages and headers
SDP
Parsing the SDP description.
Obtaining the values of different fields.
Setting the values of different fields.
Creating the SDP description by the values.
A header file that will hold the structure declarations for the above
requirements.
December 2004
5
hp-ux multimedia streaming protocols white paper
December 2004
conformance to RFCs
Product architecture
This implementation of MSP on HP-UX 11i v1 and HP-UX 11i v2 conforms to the
following Request for Comments (RFCs):
RFC 1889 - RTP: A Transport Protocol for Real-Time Applications
RFC 2326 - Real Time Streaming Protocol (RTSP)
RFC 2327 – SDP: Session Description Protocol
Figure 1 depicts the architecture of the MSP software that is supported on the
HP-UX 11i v1 and HP-UX 11i v2 operating systems.
figure 1. MSP architecture
The MSP framework comprises RTSP and SDP modules in the user space and the
RTP and RTCP modules in the kernel space. Applications can use the APIs
provided in the user space MSP library to access the kernel components,
namely, RTP and RTCP.
6
hp-ux multimedia streaming protocols white paper
December 2004
deployment scenario
The following figure depicts how MSP is deployed in a practical scenario:
figure 2. MSP deployment scenario
compatibility/ interoperability
software availability
The multimedia streaming setup, as shown in figure 2, includes two types of
interactions. The multimedia streaming server accepts multimedia data or input
from any of the following sources:
Live broadcast, such as a digital camera connected to the computer
port.
Data stored in the form of media
Data stored on machines in a network
The streaming server processes the real-time multimedia data and sends it to
the client, such as a mobile phone.
The following are the system requirements to install and use the MSP software:
HP systems running HP-UX 11i v1 or HP-UX 11i v2
1.3 MB of memory
MSP is available as a web release on the software repository of HP at the
following URL:
http://www.software.hp.com
7
hp-ux multimedia streaming protocols white paper
glossary
additional information
Following is a glossary of terms/acronyms used in this document:
Term Description
RTP Real-time Transfer Protocol
RTCP Real-time Control Protocol.
RTSP Reat-time Streaming Protocol.
For more information about MSP libraries, see the following documents available
at http://www.docs.hp.com/hpux/netcom/index.html
SDP Session Description Protocol.
HP-UX Multimedia Streaming Protocols Programmer’s Guide (5991-0718)
HP-UX Multimedia Streaming Protocols Release Notes (5991-0719)
December 2004
:
8
Loading...