Free Article: IMS (IP Multimedia Subsystem) could accelerate
fixed-mobile substitution
IMS is an open, standardised network development that increases the
flexibility and control of multimedia services delivered over mobile and
fixed IP networks. Operators implement IMS by adding to their networks a
number of new elements, as shown in Figure 1.
Figure 1 The IP Multimedia Subsystem
IMS adds core capabilities, such as multimedia session control, quality
of service control and mobility management, to an IP network. These
capabilities enable a number of service features that could each be used by
many applications, including enhanced charging, presence information, group
calling or messaging, information push and click-to-activate.
In order to justify its short-term deployment, vendors of IMS are eager
to point to a number of immediate service opportunities, such as
Push-to-Talk (PTT), video sharing, voice over IP, group messaging and IP
Centrex. However, these do not, in themselves, provide strong justification
for deployment of IMS. Operators should avoid being distracted from their
core revenue opportunities in voice and messaging into rushed decisions to
implement IMS for as yet unproven services. For example, the success of
Nextel in the USA in achieving high PTT usage and overall ARPU is being
hailed by some as an example of a strong early application of IMS. While a
number of Western European operators, including T-Mobile, Orange and
Bouygues Telecom, have launched PTT services, the short-term prospects
outside the USA are compromised by uncertain demand, risk of revenue
cannibalisation, lack of interworking, quality-of-service issues and limited
handset availability.
The strongest opportunity for IMS may be in support of the fixed–mobile
substitution strategies of 3G operators, to help them to seize significant
voice traffic and revenue from fixed operators. In the battle for voice
minutes, circuit-switched 3G voice services have the advantage of being
convenient for users, but face strong competition from low-priced, well-used
fixed PSTN services in consumer and business markets. The enhancements that
IMS can bring to basic 3G circuit-switched voice, such as presence
information, advanced voice and text messaging capabilities and greater ease
of use, will help to position mobile voice services as significantly
superior to PSTN services and will also justify their higher pricing. In the
business market, 3G IP Centrex services could offer superior mobility to
fixed network alternatives.
In the longer term, IMS may play an important role in facilitating
service convergence (supporting a common set of services across fixed and
mobile networks) and network convergence (providing cost savings with a
single, core IP network). Although there are a number of early movers in
this area, including BT, France Telecom and Sprint, widespread service and
network convergence is unlikely within five years due to complex technical,
commercial and regulatory issues.
The report Delivering Strategic Benefits with IP Multimedia Subsystem
(IMS) studies specific mobile, fixed and converged services proposed by IMS
vendors, assessing their market potential and the barriers that must be
overcome to make them a success. It also considers the role of IMS in
supporting strategic initiatives, such as fixed–mobile substitution,
converged broadband–mobile services, and integrated all-IP networks. The
report provides specific recommendations to network operators, to guide
their decisions on IMS deployment, and to equipment vendors, to strengthen
their propositions