A MULTIMEDIA IMS ENABLED RESIDENTIAL SERVICE

GATEWAY

Vitor Pinto, Vitor Ribeiro

Portugal Telecom Inovação, Rua Eng. José Ferreira Pinto Basto, 3810-106 Aveiro, Portugal

Iván Vidal, Jaime García, Francisco Valera, Arturo Azcorra

Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganés, Madrid, Spain

Keywords: Multimedia, Residential Gateway, e-Care, TISPAN-NGN, QoS, OSGi, Triple Play, Multi Play, Broadband

Network.

Abstract: Internet access has been, until now, the main driver for the generalization of broadband connections in the

residential market. Simple IP based services like email and web browsing were, during many years, the

typical services provided to residential customers. Today the telecommunications market is changing and

operators are looking for ways to provide, through those same IP broadband connections, value added

services. These will, in one hand, increase their revenues and on the other hand, provide to the customer a

wider range of services until now inaccessible. Triple Play is already a reality, although, the convergence

between mobile and fixed networks is bringing to the home a new range of IP Multimedia Subsystem (IMS)

based services, which used to be exclusive of the mobile world. Although, to successfully achieve the

delivery of these new services, the interface between residential and operator’s networks must be

meticulously defined and implemented, by what is usually called the residential gateway (RGW). This paper

focuses on emerging residential services and the implications that these impose on the RGW. The

coexistence between IMS based services and non-IMS based services are also approached on this paper,

with a special emphasis on RGW Quality of Service (QoS) issues.

1 INTRODUCTION

During the last few years the amount of bandwidth

offered by the telecommunication operators to the

residential customers has increased at an incredible

fast pace. If previous residential services were

limited to little more than email and web browsing,

the increase on the available bandwidth pushed the

appearance of bandwidth hungry services like peer-

to-peer file sharing or on-line gaming. Although

these are important services to the user, they do not

bring any additional revenue to operators. For this

reason operators are now looking for ways to

distribute added value services, like multicast IPTV,

Video on Demand (VoD), Voice over IP (VoIP),

among others, to their customers using an enhanced

broadband access network. In this context, the

European research project MUSE - "Multi Service

Access Everywhere” (MUSE, 2004-2007) was

created with the overall objective of researching and

developing a future low-cost, multi-service, multi-

provider access/edge network which allows to the

European citizens access to this whole new range of

multimedia services. The first phase of the project,

which ran from January 2004 to December 2005,

was mainly concerned with the definition of a

network architecture that allows the distribution of

advanced multimedia services to residential

customers. For the second phase of the project,

running from January 2006 to December 2007, it has

aimed the convergence of this broadband network

with mobile networks, which will result in the

combination of both architectures in a single

architectural model. This network level convergence

will be translated in the end, on convergence of

services, which means that services usually on the

domain of mobile networks will be available to

residential customers through this converged

network.

385

Pinto V., Ribeiro V., Vidal I., García J., Valera F. and Azcorra A. (2007).

A MULTIMEDIA IMS ENABLED RESIDENTIAL SERVICE GATEWAY.

In Proceedings of the Second International Conference on Signal Processing and Multimedia Applications, pages 375-378

DOI: 10.5220/0002139003750378

 SciTePress

On the other hand, nowadays, many initiatives

are being proposed on Next Generation Networks

(NGN), trying to cover the convergence between the

fixed and the mobile world. In this respect, TISPAN

group from ETSI is working on the specification of

an IMS based NGN. As a result of this ongoing

work, the first release of standards for TISPAN

NGN (TISPAN, 2006) was published at the

beginning of 2006. Nevertheless, in this release there

are several identified open issues, being one of them

related with QoS provisioning in the residential

environment. In TISPAN NGN release 1 the QoS

solution is only provided for the access network, but

the real QoS perceived by the end user is end to end.

In this respect, the work that is being performed

within the MUSE project concerning the residential

environment may be used in order to extend the

TISPAN QoS solution to the end user network.

One of the most relevant entities of MUSE

network architecture is the Residential Gateway

(RGW), which is placed at the edge of the access

network. Since the home network environment is

quite particular and different from the access

network environment, this device is responsible for

making all the necessary translations between

functionalities implemented on both networks,

making them totally inter operable and functional.

These functionalities are even more complex when

value added services are provided and convergence

between mobile and fixed services is wanted.

This article describes some of the key aspects

and functionalities that the RGW must support

considering the described scenario.

2 RGW AS A MULTI SERVICE

GATEWAY

MUSE access network allows the distribution of

multiple services using the Ethernet/IP technology,

although, in the home environment services are

sometimes terminated on end devices that do not

support this kind of technology (e.g. TVs, POTS

telephone handsets, simple medical appliances, etc.).

Therefore, a function that performs the adaptation of

service data encapsulated in Ethernet/IP to a format

that is reproducible in those end devices is required

in the home network for every specific service. In a

broader way, this functionality is implemented by

devices that are usually referred as service gateways.

Examples of service gateways are the Set Top Boxes

for an IPTV video service or an Analogue Terminal

Adapter for a VoIP service terminated on a POTS

handset. In a Triple Play scenario, usually, each

service has its own dedicated service gateway.

Although, as the number of services increases a

number of advantages arises if a single device acts

as a service gateway for different services, namely:

 Possibility of interaction between services,

allowing the generation of new services,

which is in line with a Multi Play scenario.

 As the number of residential services increases,

the configuration and management of services

will be easier if these are centralized in a

single device.

 The same approach can be used for all services

running on the service gateway regarding

access, control and personalization of services

by the user.

 The cost of the hardware platform that supports

the service gateway can be shared between the

different service providers that use it to deploy

their services.

Considering that the RGW is directly facing the

broadband access network and has several interfaces

to home network devices (where services are

typically terminated) and that all services data must

pass through the RGW, the RGW is, therefore, an

optimum point for the deployment of this common

service gateway. In MUSE RGW, an

implementation of the OSGi Service Platform

(OSGi, 2003) is executed, so the RGW can also act

as a service gateway, which can support a variety of

value added services. Advantages of using the OSGi

platform include, among others, hardware

independence, possibility of remotely install/remove

services, remote management of the life cycle of

services, remote configuration of services and the

possibility of having different services interacting, as

it is assumed in a Multi-Play scenario.

3 VALUE ADDED SERVICES

Taking advantage of MUSE multi service RGW, a

remote medical monitoring service has been

implemented as a set of OSGi bundles (software

modules in OSGi terminology). This service allows

a patient to be at home and through simple medical

equipment submit, automatically and periodically,

sets of medical measures to a hospital remote

medical database. There, they can be analyzed,

checked for alarm conditions, etc. Since all the setup

and installation of the service can be quite

complicated for a residential user, apart from the

physical connection of the medical equipment to the

RGW, all the tasks must be remotely and if possible

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automatically performed by the service provider.

Figure 1 presents the entities that intervene in the

service.

Figure 1: Remote medical monitoring service entities.

The first action is the subscription of the service

by the customer, which can be done in several ways.

One way, is through a web page, where the customer

can access and subscribe the service (Figure 1, step

1). This action triggers the automatic transfer of a

bundle (that implements part of the service) from a

bundle repository to the RGW, as well as its

installation and activation (Figure 1, step 2). When

the user connects the medical equipment to the

RGW (Figure 1, step 3), a process of drivers

selection occurs and ends with the automatic

transfer, installation and activation of a new set of

bundles that allows the communication between the

OSGi platform and the medical equipment (Figure 1,

step 4). This last set of bundles is used by the first

installed bundle and together they implement the

remote medical monitoring service. For this moment

on, measures taken to the patient by the device are

periodically submitted to the remote medical

database (Figure 1, step 5). When the service is no

longer needed, the customer can access the same

web page as before and unsubscribe the service. This

action triggers the automatic removal of the service

from the RGW (i.e. of the bundles that together

assemble the service).

As this service demonstrates, MUSE RGW

implements a service gateway that is remotely

manageable and is able to support the automatic

installation and removal of networked services,

without any input of the user regarding configuration

or management of those same services.

4 QUALITY OF SERVICE

In order to achieve the aforementioned

functionalities and to support the e-care service (or

any other added value service), the RGW must be

prepared to provide a certain degree of performance

per traffic flow. In other words, every packet

traversing the RGW (upstream or downstream

direction) must be properly treated using the

configuration parameters installed (manually or

automatically). With this mechanism, some packets

with higher priorities will be forwarded before the

lower ones. With these ideas in mind, the RGW has

been developed to provide two functionalities

regarding the QoS:

1. Configure the QoS. An end-user or an

administrator must configure the QoS

parameters in the RGW in advance. It is also

possible to configure the RGW using other

kind of methods (for example, using the SIP

information during a session establishment).

This stage could be dynamic and the

parameters could be changed during the

normal operation.

2. QoS treatment. The RGW will forward packets

as configured in the previous step.

The RGW architecture is well documented in

(Vidal, 2006) where it is explained that the RGW is

divided in two levels: the data and application level.

The data level is where the packets flow and where

the QoS is performed. The application level is used

to configure all available RGW parameters and the

QoS is one of them. The SIP method used to

configure the QoS is a bit different because those

packets are extracted from the data level and

forwarded to a special application called SIP SP

(SIP Signalling Processor). This SP uses the

information transported in the packet to infer the

QoS parameters for the next data packet flow.

An important functionality added to the RGW

architecture is the Call Admission Control (CAC)

mechanism introduced in (Vidal, 2007). With this

mechanism enabled, the RGW guarantees that all

flows will be handled as they are configured.

Whenever there is a request for a new flow insertion,

the CAC should evaluate whether it can be accepted

or not. If it is possible, the CAC must refresh the

available resources decreasing the previous ones

with the new accepted.

The CAC mechanism was defined to easily

introduce the RGW into the TISPAN NGN

architecture because it can be inserted as is (the

RGW performs a local CAC) or extended to provide

an external interface where the core IMS can

remotely configure it.

As some applications need to configure a flow

even when the resources are exhausted (for example,

for emergency calls or for the above mentioned

remote medical monitoring service) the CAC

mechanism could be deactivated using an

“unavoidable rule”.

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Figure 2: Testbed for the QoS trials.

5 CONCLUSIONS

This article presents a RGW prototype that has been

developed and trialled in a broadband access

scenario, such as the one specified in MUSE project.

The presented RGW is not only able to support the

three types of multimedia services that usually figure

in a Triple Play scenario, but also more advanced

services such as the ones considered in multi play

scenarios. In order to achieve this, the presented

RGW implements a multi service gateway which

takes advantage of the central position that the RGW

occupies in the home network. This multi service

gateway permits the dynamic deployment of

advanced added value services, such as the remote

medical monitoring service described in this article.

Moreover, the service gateway allows the remote

installation, activation and configuration of such

advanced services, without requiring any action

from the user for the services configuration and

management.

Although, in such a multi service environment,

the convergence of multiple services (i.e. of the data

flows belonging to those multiple services) through

a single device, imposes several challenges to the

RGW, namely at a QoS level. So, the presented

prototype is also able to handle the different data

flows belonging to distinct services according to

different policies (Valera, 2006). Two methods are

implemented in the RGW that permit the

configuration of such policies. The first one is based

on pre configured rules and the second one operates

in a dynamic way, using information exchanged

through signalling protocols (e.g. SIP). This last

method together with a carefully designed CAC

function implemented on the RGW, allows an easy

integration of the prototype into the TISPAN NGN

architecture. Therefore, besides the above mentioned

services, our RGW is also suitable to operate in

fixed mobile convergence scenarios, where

residential customers can take advantage of

multimedia services that used to be exclusive of the

mobile world.

ACKNOWLEDGEMENTS

This article has been partially granted by the

European Commission through the MUSE (IST-

026442) project.

REFERENCES

MUSE, “Multi User Access Everywhere”. European

Union 6th Framework Programme for Research and

Technological Development. URL: http://www.ist-

muse.org, 2004-2007

TISPAN, “ETSI TR 180 001 V1.1.1:

”Telecommunications and Internet converged Services

and Protocols for Advanced Networking (TISPAN);

NGN Release 1; Release definition.”, March 2006.

OSGi Alliance. OSGi Service Platform, the OSGi

Alliance. IOS Press. Amsterdam, 1

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