SUPPORTING MULTIMEDIA APPLICATIONS IN HOME

NETWORKS USING SIP AND SLP

Min-Xiou Chen

Department of Computer Science and Information Engineering, National Dong Hwa University, Hualien, Taiwan, R.O.C.

Bing-Yang Lin, Wen-Yen Weng

Department of Computer Science and Information Engineering, Chung Hua University, Hsinchu, Taiwan, R.O.C

Keywords: Session Initiation Protocol, Session Mobility, Home Network, Open Service Gateway Initiative.

Abstract: With increased communication bandwidth the demand for home network multimedia services is increasing.

A ubiquitous environment has been proposed to greatly facilitate human daily life. Service Location

Protocol (SLP) provides a dynamic way to search for the location of available services and service

information in the environment. Session Initiation Protocol (SIP) is an application layer signaling protocol.

SIP is used to create, modify and terminate multimedia sessions. We improved SIP to support streaming

service, and discover the streaming service using SLP. A prototype implementation is built to show the

implementation results of our prototype.

1 INTRODUCTION

Numerous home network appliances have been

developed to improve our daily life at home.

Through these home networked appliances, users

can remotely access and control home electrical

appliances from the office. Network service can

access appliances in the kitchen, living room, or

bathroom. Moreover, numerous multimedia services

are proliferating at an accelerated pace, such as the

video blog, YouTube, and audio or video stream.

With the various multimedia services, accessing,

managing and searching for desired information has

become a great challenge. Numerous different

protocols, standards and transmission modes, such

as SIP, UPnP, SLP, JXTA, and OSGi platform have

been proposed for interconnection or discovery with

these home networked devices and services.

Numerous researches (Wils, 2002) (Schulzrinne,

2003) (Bushmitch, 2004) (Schmidt, 2006) (Chen,

2009) were proposed in the services discovery issue.

Some of the proposed architectures (Bushmitch,

2004) (Schulzrinne, 2003) (Chen, 2009) are based

on the OSGi platform. With these proposed

architectures for Ubiquitous computing, the users

can easily search and access the heterogeneous

devices and services. Session mobility is the key

issue in SIP mobility management.

Some researches (Shacham, 2009) (Rosenberg,

2004) (Sparks, 2003) (Shacham, 2005) (Chen, 2007)

(Chen, 2010) were proposed in the services

discovery issue. In (Shacham, 2009), the authors

proposed mechanisms to provide session mobility

over multiple devices. Their mechanisms involved

the 3PCC (Rosenberg, 2004) control mechanism and

the REFER method (Sparks, 2003). In (Shacham,

2005), the authors integrated the service discovery

mechanism into the architecture proposed in

(Shacham, 2009). We also proposed the session

mobility over multiple devices using SIP (Chen,

2007) (Chen, 2010). In (Chen, 2007), we added the

extension header “Mobility” and introduce the

concept of “Association” into SIP to solve the

problem of session transfer. In (Chen, 2010), we

propose a complete mechanism, referred to as

“Session Integration Service”, to transfer and

retrieve a session over multiple devices.

This research constructed a digital home

environment with multimedia services. We propose

and implement a home network video stream service

based on SIP. The VoIP and 3GPP communities

have adopted SIP as their signaling protocol choice

over the past several years. SIP is an application

Chen M., Lin B. and Weng W. (2010).

SUPPORTING MULTIMEDIA APPLICATIONS IN HOME NETWORKS USING SIP AND SLP.

In Proceedings of the International Conference on Data Communication Networking and Optical Communication Systems, pages 19-24

DOI: 10.5220/0002960300190024

 SciTePress

layer signaling protocol that can be used to create,

modify and terminate sessions using one or more

devices. SIP can also be used to establish one or

multiple sessions including multimedia services,

such as audio, video and text information. However,

the video streaming services cannot be provided by

SIP.

The extension header “MediaService” is added to

SIP to provide video stream service. The control

functions for the video stream service, such as pause

and replay, are also considered in the MediaService

header. To provide session mobility, we implement

SIP UA based on the session integration service

results proposed in (Chen, 2010). We also introduce

SLP to provide service discovery in the home

network. The video stream or channel name

provided by the media server can be discovered and

accessed using SLP and SIP.

The remainder of this paper is organized as

follows. The digital home environment with

multimedia services architecture is proposed in

Section 2. Section 3 presents the digital home

environment implementation with multimedia

services. We provide the implementation results for

the proposed system in Section 4 and draw our

conclusions and future works in Section 5.

2 SYSTEM ARCHITECTURE

2.1 System Overview

Let us consider a scenario in which we are at home

during the holidays. We would like to see some

movies from a media streaming server. We may use

the TV remote control or PDA to discover the

streaming information from the local database in the

home network. When we retrieve the streaming

information from the Internet and see the movie in

our living room, we may want to move this movie to

the bedroom. We will need a session mobility

mechanism to transfer the on-going streaming movie

to the TV in the bedroom.

As we know the SIP can provide session

mobility in the network, but cannot be used to create

and control the video stream. Thus, we introduce an

extension header “MediaService” into the SIP to

provide video stream service. The system overview

is shown in Figure 1. In the home network, the SLP

DA is implemented in the residential gateway and

the media server works as the SLP SA to register its

services into the SLP DA (home DA). The Service

Integrated User Agent (SIUA) is involved in the SIP

UA and SLP UA functions. The SIUA can send a

service discovery message to the SLP DA in the

home network. Thus, the SLP DA will reply the

search results to the SIUA.

Figure 1: System Architecture.

2.2 Supporting One-way Streaming

Using SIP

When the SIUA retrieves multimedia stream

information from the SLP DA, the SIP is used to

establish a multimedia streaming between the SIUA

and media service. Thus, the extension header,

“MediaService”, is introduced into the SIP. There

are four fields involved in the MediaService header.

The type field is one byte used to describe the

streaming status provided by local services. The

value 0 indicates that this message is sent from a

one-way receiver and 1 indicates that this message is

sent from a one-way transmission. The admin field

is one byte used to describe the control command.

When the value is 0, this message is used to

establish a session and select a channel or file

carried in the option field. When the value is 1, the

control command is pause. When the value is set as

2, the control command is to play the paused stream.

When the user wants to transfer the session, the

admin value is 3. The length field is also one byte

used to indicate the number of bytes in the option

field. The option field can carry the selected channel

or the selected file name.

Figure 2 shows the established streaming session

procedure using the INVITE message. As shown in

Figure 2, when users wanted to establish a streaming

session the SIUA will send an INVITE message to

the media server. The INVITE message will contain

the MediaService header. The INVITE message is

sent from the SIUA to the media server and the

SIUA is the streaming receiver. Thus, the type field

is 0. The INVITE message is used to establish a new

streaming session. Thus, the admin value is 0. The

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user may select channel 2. Thus, the option field

value is 2 and the option field length is 1 byte.

Therefore, the MediaService header value is 0012.

Figure 2: INVITE Streaming Session.

When the media server receives the INVITE

message and the system accepts the INVITE

message, the server will return a 200 OK with the

MediaService header. The MediaService header

value is 1 because the response message is sent from

the media server, which is the streaming server.

After receiving the response message, the SIUA will

send the ACK message to the media server and

create a streaming session between the SIUA and the

media server.

When users want to pause a streaming session

the SIUA will send an INVITE message to the

media server with the MediaService header and the

value is 01. When the media server receives the

pause message, the media server will stop packet

transmission and reply with a 200 OK with the

MediaService header. The MediaService header

value will then be 11. When users wanted to replay

the streaming session, SIUA will send an INVITE

message to the media server with the MediaService

header and a value of 02. After receiving the replay

message, the media server will reply with a 200 OK

with the MediaService header (value is 12) and start

packet transmission. The detailed procedures are

shown in Figure 3.

We introduce the REFER mechanism and the

Nested REFER mechanism to provide session

mobility. As shown in Figure 4, the SIUA1 will

transfer the session between the SIUA1 and media

server to the SIUA2. The SIUA1 will send a pause

message to the media server. The SIUA1 will then

send a REFER message to the SIUA2 and the

MediaService header value will be 03. After

receiving the REFER message the SIUA2 will send

an INVITE message with the MediaService header

(value is 03) to the media server. When the media

server receives the INVITE message and the system

finds that this message is a referral message from the

MediaService header, the media server will return

with a 200 OK, transfer the session with the SIUA1

to the SIUA2.

Figure 3: Pause and Replay Procedures.

Figure 4: Session Mobility.

As shown in Figure 5 when the SIUA1 retrieves a

session that is transferred to the SIUA2, the SIUA1

will send the Nested REFER mechanism to the

SIUA2 and the MediaService header value will be

03. After receiving the Nested REFER message the

SIUA2 will send a REFER message to the SIUA1,

and the MediaService header value will still be 03.

Moreover, the SIUA2 will also send a pause

SUPPORTING MULTIMEDIA APPLICATIONS IN HOME NETWORKS USING SIP AND SLP

message to the media server. After receiving the

REFER message, the SIUA1 will send an INVITE

message with the MediaService header (value is 03)

to the media server. When the media server receives

the INVITE message and the system finds that this

message is a referral message from the

MediaService header the media server will return

with a 200 OK, transfer the session with the SIUA2

to the SIUA1.

Figure 5: Retrieval session.

3 SYSTEM IMPLEMENTATION

We integrated the SLP UA and SIP UA functions

into the Service Integrated User Agent (SIUA). We

implemented the SIUA based on the SIP

communicator project. We also integrated the SLP

SA and SIP UA functions into the media server, and

implemented the media server over the J2SE. We

need to register the service information into the SLP

DA. Thus, we installed the open-source code for

Maven jSLP into the residential gateway proposed in

(Chen, 2009), which was implemented based on the

open-source project of the OW2 Forge Oscar.

In our implementation, the jSLP is installed into

the residential gateway, which is implemented based

on the open-source project of the OW2 Forge Oscar.

In (Chen, 2009), we added an SLP bridge bundle,

referred to as “SACP”. The SACP works as SLP SA

discovers the UPnP devices and services from the

Service Registry of the OSGi platform and registers

these services and devices into the SLP DA. With

the SACP, the residential gateway can provide

automated heterogeneous devices discovery, registry

and management.

Figure 6 shows the multimedia home network

architecture. As shown in Figure 6, the media server

is involved in the SLP SA, SIP UA, and Media

Content. The SLP SA announces its service

information into the SLP DA. The SIP UA is used to

process the SIP signal procedure, such as session

established, session mobility and streaming control.

The Media Content is used to maintain the RTP

connection for the one-way streaming service.

The SIUA contains the SLP UA and SIP UA

functions and we implement the SIUA based on the

SIP communicator, as shown in Figure 7. The SIP

communicator has two major modules for network

communication. The Sip Manager is used to process

the SIP signaling function and the MediaManager is

used to maintain the RTP session. When the SIUA

wants to create a streaming session, the SipManager

will use the SendRequest() function to send the

INVITE message to the media server. When media

server wants to reply to the message, SipManager

will use SendOK() function to reply to the message.

The MediaManager will then create a RTP session

between the media server and SIUA, and use the

SendStream() function to send the packets.

Figure 6: The Multimedia Home Network Architecture.

Figure 7: The SIP UA Streaming Service Architecture.

4 IMPLEMENTATION RESULTS

As shown in Figure 1, we conducted experiments

with our prototype implementations to ensure the

location service ability and streaming service session

mobility. In the first approach, the media server

registers the streaming services into the server. The

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SIUA1 then sends a Service Request to the DA1 to

discover the streaming service, as shown in Figure 8.

When the SIUA1 receives the Service Reply, the

streaming service information will be shown on the

GUI, as shown in Figure 9.

The SIUA1 and media server then create a

streaming session. The SIUA1 will then transfer the

session to the SIUA2, as shown in the left of Figure

10, and the session between the SIUA1 and media

server will be transferred to the SIUA2 and media

server, as shown on the right side of Figure 10.

Finally, the SIUA1 will retrieve the session between

the SIUA2 and media server, as shown in Figure 11.

Figure 8: SLP Service Request Packet.

Figure 9: SLP Request Search Results.

Figure 10: Session Mobility.

Figure 11: Retrieval Session.

Figure 12 shows the media server packet traffic.

From Figure 12, we can find that the SIUA1 creates

a streaming session with the media server after 9

seconds, and the traffic between the SIUA1 and

media server is increased after 9 seconds. The

SIUA1 transfers the session to the SIUA2 after 17

seconds, the traffic between the SIUA1 and media

server is empty and the traffic between the SIUA2

and media server is increased after 17 seconds. The

SIUA1 retrieves the session, the traffic between the

SIUA1 and media server is increased and the traffic

between the SIUA2 and media server is empty after

24 seconds.

SUPPORTING MULTIMEDIA APPLICATIONS IN HOME NETWORKS USING SIP AND SLP

Figure 12: Packet Traffic of Media Server.

5 CONCLUSIONS AND FUTURE

WORKS

The Internet has grown to an enormously large scale,

with ubiquitous computing receiving increased

attention over the past few years. In a home network,

providing service discovery and multimedia services

has become a great challenge. This paper proposed

and implemented a video stream service for a home

network based on SIP. The MediaService header

was added into the SIP to provide video stream

service. With the MediaService header and REFER

method, streaming service session mobility can be

provided. With the SLP, the SIUA can discover

services from the SLP DA and access the media

streaming from the media server. Application

examples were introduced and the implementation

results show the ability of the proposed architecture.

In the future, we will extend our proposed

architecture with OSGi platform capabilities to

support an intelligent Home network system and

intelligent Vehicle network system.

ACKNOWLEDGEMENTS

This work was supported by the National Science

Council of Taiwan, R.O.C. under Grant NSC96-

2221-E-216-010, NSC97-2221-E-259-036, and

NSC98-2221-E-259-014.

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