A Proper Startup
for Network Transformation
Huawei Softswitch + SHLR + MSAN solution
I. Network Transformation -- Challenges and Opportunities
for Network Carriers
Traditional carriers are now facing three main challenges:
A. Saturation in fixed-line and wireless voice markets.
B. Continued erosion of TDM service revenue by IP and VoIP telephony.
C. Lack of an effective strategy and sufficient profit margins for
The need for transformation
The prevalent trend in the telecom market exhibits wireless technologies
replacing fixed-line telephony, voice services giving way to non-voice
services, and ICT convergence superseding traditional business services.
The fixed network market has undergone substantive, structural changes
in terms of increasingly demanding market requirements, the impact
of technological progress and fresh challenges due to increased
competition. Telecommunications is now focused on the integration
of multimedia information and the convergence of IT and CT in corporate
applications. Furthermore, there now exists a greater emphasis on
mobility and personalized and customized services. Technological
advancements have given rise to lost cost new technology, more rapid
deployment methods and an unprecedented ease of market entry. IP
and mobile technologies are the fastest developing applications
and, compounded by polarized competition, cheap mobile voice and
VoIP telephony and VoIP services are shattering the tried and tested
"license + voice" service delivery pattern. Structural
transformation is therefore inevitable for network carriers, and
this is in fact necessary to guarantee survival in the marketplace.
The nature of transformation and NGN
This of course raises the question of defining clear goals relative
to the nature of this transformation. Some common viewpoints have
been found after analyzing the cases and strategic plans of various
globally leading carriers, including BT's 21st Century plan, Telstra's
Future Network Evolution and NTT's Resonant Communication Network
Architecture. It is the belief of these companies that traditional
carriers must shift perspective to become more holistic and integrated
information service providers in order to reflect the fact that
networks are moving inexorably towards convergence, broadband and
'Convergence' can be defined as multiple networks of services
being combined into a single network providing multiple services;
'broadband' refers to the evolution of narrowband networks to broadband
networks; 'intelligence' means the transition of intelligent networks
to network intelligence. Traditional to NGN network evolution occurs
in two stages. Firstly, NGN is used re-construct PSTN. Secondly,
corporate and home subscribers are provided with converged Information
Communication Technology (ICT) services.
II. Network Transformation: Starting from Softswitch +
SHLR + MSAN
Based on an understanding of future network transformation, Huawei
proposes a solution utilizing "Softswitch + SHLR + MSAN",
as shown in Figure 1.
There are four layers to this solution:
1. A service and management layer.
2. The network control layer.
3. The core-switching layer.
4. The edge access layer.
The service and management layer is an open and integrated service
platform that provides service logic processing in terms of creation,
logic definition, programming interfacing and management. The network
control layer consists of softswitch and SHLR (Smart Home Location
Register). The softswitch comprises the network's service control
center, which provides control functionality, control and command
of media gateways and access devices, signaling protocols' processing
and CDR generation. The SHLR in these terms encapsulates a user
profile center that acts as the central database detailing every
network subscriber, their attributes and subscription service properties.
Additionally, the SHLR can store subscriber profiles in networks
other than NGN, such as PSTN or PLMN, as well as storing logical
and physical number maps. The SHLR, softswitch and service platform
are designed to enhance service provision across the entire network
(NGN, PSTN, and PLMN).
The core-switching layer adopts packet switching technology, and
provides a highly reliable, guaranteed large-bandwidth integrated
switching platform. The edge access layer contains MSAN (Multi-Service
Access Network), an integrated access gateway solution that provides
various kinds of access interfaces including POTS, ISDN and xDSL.
Combining softswitch and SHLR in terms of the solution as a whole
brings intelligence to the whole network. MSAN is positioned as
the access layer, thus enabling the provision of new broadband services
by broadening last mile bandwidth. The features of convergence,
broadband, and intelligence are reflected in all four layers of
- Convergence oriented Network
At the access layer, the existing multiple access equipment -
traditional switch, DSLAM and AN - are replaced by one MSAN, which
embodies a unified access platform and significantly decreases the
required number of access nodes. Diversified access service needs
are met including ADSL 2+, VDSL, LAN, FTTH, WiMAX , PBX, POTS and
ISDN.. At the core-switching layer, legacy PSTN, data and Internet
networks are replaced by a shared IP network.
The service layer enables centralized user profile storage and network
call control, which realizes the goals of service convergence and
rapid service deployment. Voice, mobility, multimedia and Internet
converged services are readily expedited.
- Broadband oriented Network
MSAN introduces various broadband access methods at the access
layer and increases last mile bandwidth to meet user broadband service
requirements. At the core-switching layer, the network is constructed
utilizing sufficient, guaranteed core bandwidth to ensure high quality
and the ability to meet growing service needs.
- Intelligence-oriented Network
At the service layer, the existing separated intelligent networks
- fixed, mobile and APP server - are replaced by one unified, intelligent
service platform. The centralized subscriber data center and service-switching
center brings intelligence to the whole network and supports speedy
and unified service deployment.
Initiating network transformation with Softswitch + SHLR + MSAN
offers users a plethora of benefits:
1. Simplified network architecture
Serving as independent call control nodes in the traditional local
network, the legacy switch can be defined as an all-inclusive, small
capacity piece of equipment. In order to actualize large-scale deployment,
numerous offices are usually established in a small area to build
a layered network such as C1, C2, C3 and so on. This can give rise
to over-complicated network dynamics, rendering PSTN hard to maintain,
update and expand.
Large capacity softswitch + MSAN denote the most practical and
cost efficient solution to solve this problem. The softswitch contains
a powerful processing capability to support local subscribers, and
the different Media Gateways bundled with this solution offer different
capacities and circumstantial adaptability. MSAN, which can support
thousands of subscribers, possesses an internal switching function
that is suitable for relatively densely populated areas or significant
subscribers. If the bearer network between softswitch and the MSAN
fails, MSAN subscribers can still communicate. Furthermore, the
'MSAN Outdoor Cabinet' boasts an all-in-one design incorporating
power supply, MDF, battery and air-conditioning system for outdoor
With this solution, one Softswitch system is capable of covering
a very large area. Not only is the structure of the network simplified,
call failures are greatly reduced. The system as a whole offers
unequalled robustness and a dramatic reduction in terms of total
investment expenditure in equipment, external lines and maintenance.
Moreover, by adopting optical fiber transmission, this solution
can satisfy the requirements of both today and the future.
As Figure 2 illustrates, the Softswitch + MSAN solution reduces
the number of host switches from 10 to 1. All subscribers receive
centralized softswitch control that is accessed through MSAN, and
switch coverage is extended from 3km to tens of kilometers. Given
that the MSAN receives centralized control and monitoring from the
Softswitch, this aspect of maintenance expenditure is considerably
lessened. Since the lower-level, small capacity legacy switches
are replaced by an MSAN, the local network is unified. Therefore,
call connection times are shortened, call completion rates are increased,
network safety and integrity is enhanced, and the cost of upgrading
and overall maintenance reduced.
2. Bringing intelligence to the whole network
The SHLR operates in a similar manner to the HLR in a mobile network
and the HSS in IMS. It functions as the central database for all
subscribers in the network and stores the mapping between logical
numbers and physical numbers, as well as recording subscriber attributes
and subscription service properties. This methodology delivers operators
the following benefits:
- Quick and low-cost network-wide coverage of IN services. All
calls in the network are controlled and billed via the softswitch,
which acts as the service control center. All subscriber data
is stored and managed by the SHLR, the subscriber data center.
The development and deployment of services are no longer limited
by physical lines, and numbers located in the LEs are scattered
over different geographical locations. The solution can provide
IN services such as Colorful RBT, ONLY, PPS, WAC, new intelligent
phones, MVN (Multiple Virtual Number) to all subscribers without
upgrading the LEs. Thus network profitability is boosted.
- OPEX is reduced by centralized management, maintenance and
subscriber data authorization
3. Investment protection
Huawei's "Softswitch + SHLR + MSAN" solution can consolidate
all PSTN service capabilities and facilitate development without
losing current subscribers. It therefore supports service transformation
in a manner that is forward-looking, proactive and reactive to the
future direction of the industry. The access network is a key component
of the local network, requiring the greatest portion of CAPEX, and
it forms the access and transfer platform for all service networks
including PSTN, ISDN, DDN, FR, ATM, and IP. At the moment, voice
service is still the principal network service, but with the rapid
development of packet services, packet traffic will ultimately exceed
TDM traffic levels. The access network provides access to all service
and local telephone networks and inherently possesses the capacity
for evolution to NGN. The use of MSAN in the NGN's access network
reduces CAPEX and OPEX and allows future service integration and
deployment to take place.
MSAN – key benefits
- MSAN is an integrated access device that can access services
such as POTS, DDN, FR, ATM, and IP. Therefore, carriers do not
have to build and maintain multiple service networks.
- Huawei fully considers the trend of future service development
in MSAN system design. It is designed with a triple-bus structure
- ATM, TDM, and IP. All access modes are supported, as is the
deployment of the ANY PLAY service. Carriers are not required
to upgrade MSAN to support new future services.
- The MSAN provides high-density, narrowband and broadband hybrid
boards, increasing port density, reducing cabinet size; simplifying
cabling and minimizing cabling space. OAM is simplified, reducing
CAPEX and OPEX.
4. Enhancing service capabilities
With MSAN's broadband access capability, the network control center
softswitch and the SHLR data center provide richer services spanning
multimedia, third-party and network management. Service provision
takes place together with the ENIP, a comprehensive service platform.
The development cost of Softswitch's new services is only 20% that
of traditional telecom networks, and the development period is only
10% that of PSTN.
Services and capabilities
1. Traditional PSTN/ISDN basic services, supplementary services
and Centrex services. This covers traditional phones as well as
SIP and H.323 multimedia phones.
2. Multimedia Application Services, including point-to-point video
services, video conferencing, IP TV, interaction between multimedia
phones and 3G handsets, and various types of multimedia integrated
3. Value added services include new intelligent phones, iCard
integrated account cards, IN public phones, colorful dial, background
and ring back tones (CRBT), instant billing, remote handset address,
caller authentication, ONLY, VPN, FFPH (family free phone), FPH,
voice address books, audio cards, voice SMS, voice mailbox, advertisements,
designated phone payments and an IP card service.
4. Third-party open API. The softswitch and the ENIP platform
provide an open API so a third party may develop customized and
personalized services. The softswitch can access the Application
Server through standard SIP protocol, and traditional SCP through
INAP in order to provide traditional and new value added services.
The ENIP benefits from flexible and versatile network capability
opening models, providing openings to CORBA, Web Services (SOAP)
and RMI. ENIP supported features include standard Parlay interface;
expanding Parlay with carriers and customizing API. This allows
a third party to manage the service release based on workflows,
and provides a universal Portal for subscribers to query and subscribe
to third-party services, for example, SP and CP management, subscriber
service orders, and bill settlement.
5. Integrated Information and Communication Technology
The convergence of communication and information technologies
underpins network transformation, which will ultimately bring huge
benefits to fixed-line operators. Convergence occurs in all aspects
of carrier-class services, ICT devices, software and IT services,
outsourcing included. In the network layer, the softswitch + SHLR
+ MSAN open network structure provide a basis for ICT. The network
can provide broadband access and interconnectivity, IP Centrex,
UC, web800 services for corporate subscribers and, for personal
subscribers, IPTV and digital home services.
IP Centrex: A wide area IP Centrex grouping can
be established for a single enterprise, inclusive of its HQ and
branches. It enables both analog and video subscribers to communicate
with each other in the same Centrex group, even if the subscribers
are located in different cities. Additionally, U-Path is provided
to ease self-service management.
UC: UC takes advantage of both real-time communications
systems and easy-to-use IT platforms, and can provide click to dial/fax,
instant messaging, intelligent routing, unified messaging, directory
services and self-service for high-end business subscribers with
Web800: This allows subscribers to call an enterprise's
call center or helpdesk by clicking the web800 icon on the web page.
The service is targeted at the manufacturing, service, financial
and logistics industries.
Digital home: With the increased move towards
broadband network construction, fixed terminals, otherwise unchanged
over decades, are afforded new opportunities. By taking advantage
of broadband, new home terminals – in other words the digital home
gateway - will integrate telephone, PC, and TV to provide an all
inclusive user service.
III Further Network Development
Proposed by 3GPP and widely accepted by international institutions,
IMS research into the wireless and fixed-line fields is helping
steer the advent of network evolution. The features and benefits
of IMS include an open service environment, mobility, flexible service
deployment and unified home service settings. IMS facilitates a
seamless convergence of fixed-line and wireless networks, and provides
ICT services. It is designed to allow all services to share the
same core network, subscriber database, background billing system
and service development platform. Subscriber data management and
roaming capacities are subsequently enhanced.
The IMS is the future of fixed-line and wireless networks, and
the IMS-based fixed-line/wireless converged network is generally
regarded as the best solution. Nevertheless, the mobile-oriented
IMS still requires conclusive research with respect to access models,
service provision and fixed-line network subscriber migration. There
is still a long way to go before IMS standards are completed, and
consequently before the first commercial IMS network is deployed.
Equally, sufficient maturity of the entire telecommunications industry
is a tangent yet inextricable aspect of the transformation process.
The softswitch and IMS are regarded as the two stages of NGN development.
The softswitch has present applications, solving high OPEX and inadequate
service capability issues in legacy PSTN networks. Conversely, IMS
application will occur in the future: the system is set to provide
IP multimedia services and shoulder the convergence capability of
fixed-line and wireless networks. The softswitch-based network shares
the same network topology as IMS, including Access, IP Bearer, Session&Call
control. The evolution from softswitch to IMS is therefore smoothly
handled and realized.
Huawei's Softswitch + SHLR + MSAN solution offers flawless evolution
capabilities to IMS with minimum network impact. Below is an illustration
of the evolution process:
The Softswitch can be upgraded to provide the IMS AGCF/MGCF function
without adding any hardware. This approach requires SHLR to provide
the IMS HSS function. The IMS is intended as an NGN subsystem that
can act as an SIP based multimedia system and provide new value
added services for all network subscribers. Existing POTS users
must still access the NGN via MSAN and can enjoy traditional PSTN/ISDN
services provided by AGCF/MGCF. AGCF/MGCF will share the same HSS
user database with other IMS components.
As fixed-line operators are evolving from traditional network carriers
to integrated information service providers, a sustainable network
is required to support convergence, broadband and intelligence.
Huawei "Softswitch + SHLR + MSAN" is the best choice to
initiate this transformation and guide future network direction.