MSOs have achieved great success with their deployments of on-demand video and data services for the residential market, but rising competition has brought MSOs face-to-face with two important challenges: on the one hand, maintaining their competitive edge and stronghold in the residential video services market, and on the other, venturing into new revenue-generating segments to enhance their service portfolio.

The two objectives, namely the differentiation of residential video content and the move into new segments such as mobile backhaul and enterprise services, require operators to rethink their network architecture and aim for an optimized, carrier-grade infrastructure that will allow them to effectively compete in both the residential and business segments.

So what does an optimized network mean? What services does it need to offer? And most importantly, what is the right architecture that supports these services?

In the residential market, an MSO’s core offering is centered on its video service and the ability to sustain its market leadership with regard to content variety, interactivity and overall customer experience.

Those abilities have a considerable impact on network architecture, and their availability defines how an operator approaches the right network implementation. To understand the implications involved, let's first consider the services found or planned in mainstream MSO offerings.

Video quality:

  • HDTV – For premium content
  • SDTV – For standard content
  • Tolerable standard TV – For watching Internet content quality (such as YouTube) over TVs and widescreens
  • Split-screen or picture-in-picture – For example, combined big-screen HDTV with an SDTV window on the same screen
  • VOD/SDV – Viewing unicast content according to customer choice with trick mode options (play, stop, fast-forward and rewind)
  • Series subscriptions – The right to access and view episodes of a series or other content in VOD/SDV mode
  • Time-shifted TV – The ability to view content after the time of the original program as if it were VOD/SDV content
  • Digital video recorder – Usually part of the MSO STB; enables recording one or more channels at the same time as viewing that program or another channel
  • Network PVR – The same as DVR, but over the network
  • Personal advertising – Enables the insertion of local advertisements per geographical area, or even unicast personalized advertisements, according to the viewer’s profile
  • TV-Web connection – Enables the customer to access details about products/services advertised on TV by linking to the relevant Web page
  • Voting – Using the two-way cable system for mass voting during reality programs such as American Idol, Survivor, etc., instead of sending SMSs
  • MMS – Multimedia message services text, voice, video between viewers over the TV

Being bi-directional and interactive in nature, some of those advanced services are significantly more bandwidth demanding and require a robust network architecture that enables the transmission of large amounts of bandwidth and allows the service provider to assign the appropriate QoS for each type of service. The network also needs to be able to monitor and respond, in real time, to the significant amount of data being generated – both from the customer premises and the network itself.

Deploying and maintaining a network capable of such robustness and bandwidth capabilities requires a different approach to network architecture design – one which demands the capabilities made possible mostly by a carrier-grade packet optical platform solution, which extensively supports QoS per port, per user and per service type.

Scalable MSO Infrastructure

The advent of enterprise services and mobile backhauling in the business sector has provided MSOs with a new frontier, one that will allow them to strengthen their financial model and expand their market penetration and foothold.

The business segment is attractive to MSOs for a variety of reasons, an attraction that is driven by the flattening of revenue growth in their traditional, and saturated, sector of operation – the residential market. The business segment, on the other hand, is still growing strongly, and for MSOs, the high-margin revenues associated with the business market are a compelling attribute.

Suffice it to say, the attraction is mutual – enterprises are also keen for MSOs to venture into their market, primarily for their ability to provide a suite of triple-play services, but also to form a competitive bargaining tool against current service providers.

An average MSO offering includes suites of voice and data services. These data services should include Layer 1 SONET-based connections starting from T1 up to OC192, TDM-based connections of storage bit rates (ESCON, FCx and FiCON), Ethernet-based Layer 2 services starting from E-Line up to L2VPN, and IP-based Layer 3 services up to L3VPN.

We note that similar to the residential market, the business segment requires high-capacity capabilities along with a variety of QoS support. In addition, it also requires the support of a mixture of Layer 1, 2 and 3 services, all of which are important considerations for optimal network design.

With this in mind, an optimal MSO network architecture should be able to support the needs of both the voice and data service portfolios and allow an operator to compete effectively across the two segments – residential and business alike.

But the question remains how an optimal architecture is to be shaped and what it should include. For that, one needs to review the two most important parts of any MSO network separately – namely network access and the metro core.

Most of the cable infrastructure in the access piece is already hybrid fiber/coax-based topology, which means that fibers are already deployed deep into the metro/access areas and, in many cases, the existing DOCSIS system can serve most of the service needs of both residential and enterprise sectors.

In greenfield areas, business parks, and in cases in which the network has not adapted yet to the new HFC topology, MSOs have the option to consider FTTB/EPON technology to better utilize network resources and cope with the growing demands for bandwidth. In recent years, we have found that EPON has become a very attractive access technology for businesses and mobile backhaul services, and for residential services with more upstream bandwidth demands.

When looking to offer IP-based services, the MSO’s metro/core needs differ from those of traditional cable TV operators that downstream broadcast channels to customers.

Having a bi-directional access network requires a metro cloud to efficiently perform the various interconnections of the overall traffic and supply the necessary services to customers. Those services can include the transmission of TV channels in SD and HD format from the headend, VOD content from the server farm to the hubs, and data distribution for both residential and business customers. Last but not least, the network must also support mobile backhaul aggregation, which needs to simultaneously carry TDM, ATM and Ethernet connections so it can cater to the multitude of cellular technology generations – 2G, 3G, and even 4G.

The metro/core part of the network requires a carrier-grade solution that is robust enough to cope with today’s needs, as well as enable future growth. The ideal solution is a Carrier Ethernet Switch/Router (CESR) that has the following attributes and will provide all Layer 2 and Layer 3 functionality:

  • Large amounts of capacity
  • Combined efficient IP and Ethernet functionality – Flexible switching and routing mix in a single platform
  • Full-service support – Hierarchical QoS (H-QoS) with multicast for E-Line, E?LAN, E-Tree and IP-VPN services
  • Capacity and scalability – Switching and processing capacity to meet both current and future service needs
  • Reliability and availability – Bringing five 9's reliability to Ethernet services

In addition, the metro/core must include an optical layer to efficiently interconnect the CESR products with large amounts of bandwidth, and also provide Layer 1 connectivity services – GigE, SONET, wavelength and sub-wavelength services for business customers.

The optical solution can be constructed in a ring or mesh topology according to the operator’s geographical spread, and it must provide the following attributes:

  • Wavelength management – Two-degree and multi-degree ROADM options
  • All-range support – Wide range of optical options, including dynamic gain low- noise optical amps
  • Capacity flexibility – 10G and 40G support on 16, 32, 40 and 80 channel systems with protection options
  • Ease of operations – Managed solution with automatic power control, C band-tunable transceivers, etc.
  • Sub-wavelength management – Layer 2 and especially GigE connections support, SONET, and TDM aggregation and grooming support

In sum, it is changing times and the competitive landscape that force MSOs to increasingly evaluate their service offering, and as such, their network architecture.

With a long-standing track record in remaining a competitive player, there is no doubt MSOs will continue to take advantage of the opportunities that come their way – by utilizing innovative networks, which will support both residential services, as well as carrier-grade business and mobile backhauling services.