The MSAN migration path: maintaining legacy services while moving to a next-generation network��all in a cost-efficient way��is the MSAN promise to operators

Operators and service providers are currently facing a dilemma. New broadband services, such as the delivery of entertainment and advanced methods of communication, are increasing in both volume and traffic mix. However, the take up of these new services has proved to be unpredictable and customers are moving from usage-based charges to 'all-you-can-eat' flat-rate pricing tariffs. Operator business models, which have previously proved very successful, are now being challenged. Profitable services, such as fixed voice--the former cash cow of the operator--are now under extreme pressure from regulation, mobile substitution and VoIP.

Today's network operator must maintain a variety of access boxes to support multiple services. Voice services, for example, can be deployed over a digital loop carrier and data services via a DSL access mux (multiplexer). Additionally, the networks on which that traffic is carried is often completely separate and stovepipe-oriented with a high associated operating cost structure.

Furthermore, PSTN equipment in a number of major European incumbent's networks is starting to reach the end of its useful life. When this happens, the cost of managing the equipment will increase dramatically. Operators will also find it increasingly hard to source spares for the network as vendors decrease the amount of investment in these product lines in favour of next-generation network (NGN) equipment, such as softswitches.

These pressures are driving service providers in developed markets to take substantial costs out of their network operations--and do it quickly--while at the same time protect existing revenue streams for as long as possible to generate the required cash flow to fund the network restructuring.

Therefore, the evolution of the access network must include: built-in migration from xDSL to FTTx; continued support of mixed technologies (copper, optical and radio interfaces and multiple xDSL flavours); ability to handle packets, cells and TDM on the same platform; and uniform provisioning and management capability.

Collapsing the access layers and creating a single end-to-end network will, in the long term, reduce the cost of the network and enable new broadband services to be delivered profitably. The deployment of multiservice access nodes (MSAN) achieves these goals today.

The MSAN concept

A MSAN (multi-service access network) can be defined as a single piece of access equipment that can provide multiple types of services to a range of different customers. MSANs were originally designed to be placed in a small community to address all its communications requirements. Traditional designs had a range of slots to accommodate different types of line cards and dual busses to handle both TDM and data. Today the principle stays the same, but new technology deployed on products--such as the Marconi Access Hub--allow for any card in any slot; high-density combination DSL and POTS line cards; and media gateway functionality that allows seamless interworking with softswitches for packetised voice delivery.

Thanks to the sheer amount of nodes within it, a network's greatest operational costs are related to the access segment. Amid promises of less equipment and lower operating expenses, access networks are moving towards convergence--collapsing layers and consolidating services onto single-access platforms.

To clarify and demonstrate the cost savings enabled by MSANs, Marconi has modelled the business case for deploying its MSAN in real network scenarios and has found the operational savings to be considerable in the key areas of:

Network simplification

Business case modelling has demonstrated that the use of a MSAN will enable a next-generation access network to be built with a reduction in the order of 70 per cent in active devices. This has obvious immediate impact on reducing power consumption and increasing the reliability and responsiveness of the network to deliver services.

Estate rationalisation

A high density of MSANs allows the equipment to occupy a significantly smaller footprint than other technologies. On a like-for-like basis in delivering voice services, it's possible to offer a 66 per cent reduction in footprint over traditional voice equipment, DLCs and concentrators. This presents a great opportunity for operators, typically incumbents who house their equipment in prime real estate areas, to generate additional revenue from the sale high value properties.

Remote service provisioning

An example of the growing use of software is found in the development of Marconi's high-density combo card, which can remotely provision both voice and broadband. Operators have the flexibility to initially provision voice or broadband, adding the complementary service when required and thus enabling substantial reductions in operational expenditure as no manual intervention is needed.

Capex

With any network transformation there is an associated initial capital outlay, but the deployment of a single access technology, which can handle multiple services and collapse access layers, will future-proof network investment while also moving to a lower repeat capital investment cycle. In addition, provisioning all services from a single platform, such as a multi-service node, can enable enhanced services that were not previously feasible from either an economic or technical perspective. Historically, the inability of data networks to provide acceptable quality of service levels for time-sensitive and mission-critical applications like voice and video has been a barrier to convergence, which the MSAN overcomes.

Who is deploying MSANs?

Incumbent operators such as BT have announced ambitious NGN plans and the MSAN concept is at the heart of that strategy. Telecom Italia and TeliaSonera have also presented future network strategies, which include MSANs. Alternative operators in Europe have also seen the benefits with Wind in Italy being a notable example.

The MSAN market also presents a great opportunity to access equipment vendors. The opportunity is much larger than sole DSL contracts as MSANs will eventually replace other access boxes including the PSTN exchange. Currently in Western Europe there are approximately 150 million PSTN customers compared to only 27 million of DSL services. Even by 2010 the difference between DSL and total fixed lines is likely to be around 50 million lines, hence vendors need to invest and closely examine the MSAN concept.

Andrew Povey, vice president, access, Marconi

written by Andrew Povey

COPYRIGHT 2005 Horizon House Publications, Inc.
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