Triple Play

Telcos and service providers in the world over are racing to deploy networks that will support the triple-play service bundle—the delivery of voice, video and data services provided on a common network infrastructure. And although there is no agreement among providers in terms of a single plan for such an infrastructure, providers agree that the triple-play represents a major opportunity to forestall the growth of cable MSOs and other competitors.

The availability of new, carrier-grade IP-based technology is also contributing to a major shift in the way providers are designing their networks to provide new video and enhanced telephony services. Indeed, the reality of a true converged, IP-based network architecture opens the door to an array of enhanced applications and services, including IPTV, video telephony, VolP, and Video on Demand.

Telco Triple-Play: The New Mandate for Today’s Service Providers

Telcos can no more rely on the revenues from POTS as the upstart VOIP providers and Cable MSOs are gearing up for full-scale services in the IP region that will include video, voice and date. The way cable broadband is progressing in India, telcos are facing their moment of truth—either upgrade their infrastructure and expand service offerings or endure a slow and steady contraction of their subscriber base and revenue streams.

With the lines drawn in the battlefield, the strategy is clear: telcos must add their own video services — including video telephony, broadcast video and video-on-demand — to their current voice and data offerings in order to effectively compete in today’s marketplace. 

Clearly, there are significant business opportunities for the telco offering a triple-play service bundle. Apart from protecting their subscriber base from churn, video service has the potential to grow a telco’s ARPU (annual revenue per user) by 100%, something that no other service offering can currently provide. But, there are also significant challenges ahead for the local telcos: key strategic issues include how to cost-effectively deploy triple-play infrastructure in their extensive networks, and how to best deliver triple-play services to millions of subscribers’ homes in a reliable manner.

Key Elements of Triple-Play Deployment

Three key issues necessary for the successful understanding, development and deployment of a triple-play network are: -

a) Every Implementation is different. The variety of possible video deployments and the need to interwork with legacy networks means that there is no “one size fits all” solution.

b) The user experience is based on proper operation of (i) the triple-play applications, (ii) the services provided by the service provider and (iii) the underlying infrastructure.

c) A clear understanding of both the individual point elements in a network and their function as a dynamic interactive system are required to operate a successful triple-play network and pinpoint diagnosis of problems as they arise.

The Different Approaches to Achieving the Telco Triple-Play

Currently, there are a number of different plans for triple-play infrastructure, each with their own set of challenges. Additionally, there is currently no common approach to defining network requirements or agreement regarding the appropriate level of service for voice vs. data vs. video.

Fiber to the home

A FTTH Triple-Play architecture, while still costly to implement over long distances, offers virtually unlimited bandwidth—currently 50,000 times the capacity of coax cable, or 50 Terahertz vs. 1 Ghz. The same type of multicast video distribution architecture can be employed as a cable MSO.

On an interesting note, the digital cable service offered by MSOs today is actually transmitted in an analog format, in such a way that enables cable companies to increase the channel capacity of their systems. In current systems, up to five video channels are converted to a digital format, multiplexed, and then converted into an analog format and sent in a single 8-MHz channel slot for transmission. This way, digital channels can be combined with traditional analog PAL channels on the system. Cable systems currently support more than 100 8-MHz channel slots, which allows them to offer the 500 or so channels currently in the channel lineups today. While a TV tuner can access and select analog channels, a set-top box is required to select and decode digital channels.

Fiber to Node

In contrast, FTTN architecture employs fiber up to the local distribution cable. From that point on, the service would run over copper loops to the subscriber using DSL. The advantages of this approach are that it leverages the existing twisted pair infrastructure – something the telcos own a huge amount of – as well as their sizeable investment in DSL technology. The downside is that the copper local loop doesn’t have nearly the same capacity as fiber.

The challenge for the telcos, even with these new developments, is that there will still be a need for even greater capacity, considering that the infrastructure will have to support not only a multitude of standard and high definition video channels, but also broadband Internet and voice. Some options include aggregating links for more bandwidth, and creating new, more efficient error correction and encoding algorithms to squeeze more capacity out of VDSL2, but even these methods won’t be enough to solve the bandwidth dilemma.

Telephone

With respect to voice, current options are to transmit telephone service in the old analog way, on low-frequency portion of the local loop as it’s currently performed with today’s ADSL services, or to migrate to a VoIP offering. The analog method reserves the available 25 Mbps for video and broadband Internet, but leaves subscribers with the same old POTS service that they’ve always had. A migration to VoIP, on the other hand, allows telcos to effectively counter the threat from the cable companies and upstart broadband telephony providers, and offer a far richer application/feature set in the process.

Delivering a Packet-based Voice, Video and Data Service Bundle

As we’ve discussed above, even with more efficient coding algorithms and new versions of DSL, Telcos that follow the FTTN path to triple-play deployment will still hit a wall in terms of capacity where a 25 Mbps connection isn’t enough to support the services required. As a result, these telcos are eyeing a new IP-based network architecture employing gigabit Ethernet technology.

In fact, IP is emerging as the telcos’ most potent weapon in their technology arsenal. The migration to a converged, P-centric network infrastructure enables all service providers to become full-fledged triple-play providers, allowing them to leverage multiservice IP access solutions to provide a common network platform for video, data and voice over. In fact, the deployment of switched digital video services could potentially favor the telco in the battle with cable: most large telcos have an innate understanding of switched services, and have the operational infrastructure to effectively support massively scaleable switched services to boot.

Quality of Service (QoS) Issues

Since it’s still not clear which delivery and pricing models and applications will gain market acceptance, the availability of a high speed broadband connection is simply not enough. Telcos must design their broadband delivery infrastructure to support the delivery of high-speed, QoS-sensitive applications, regardless of what they are or how they are billed.

One such service delivery challenge involves IP TV. In an FTTN deployment, IP multicasting will be employed with channels terminating at a local neighborhood concentrator. Up to five TV channels and Internet service will be delivered to a subscriber—a model that is radically different than the delivery method employed at cable MSOs. With only five channels at a time sent to a subscriber’s set-top box, a signaling protocol is now needed to send an alert to the concentrator when a subscriber requests a new channel.

A big unknown problem with this mechanism is that, what the response time of the network video server will be. From a competitive standpoint, the channel change (join and leave times) must be as quick as it is with today’s digital cable service.

PROBLEMS IN A TRIPLE-PLAY SERVICE

Data Packet Loss

For email and HTTP traffic, a few lost packets are no big deal. As long as packet header Information is in order, the packets will re-assemble themselves at the destination without any apparent change or perceptible loss to the end user. But in an IP-based triple-play network even a low level of packet loss can create unacceptable degradation of voice and video traffic quality.

Packet loss can result in everything from garbled voices on a phone call to graininess and dropouts in a video signal, where the screen during a video conference or TV show loses clarity or momentarily goes blank. In the worst case, severe packet loss can cause an entire communication session to be dropped by the network, meaning that a phone call gets disconnected or video session abruptly ends.

Voice and Video Jitter

The time it takes for packets to travel from point to point within a converged network is measured in delay or latency levels. Jitter is a variation of delay/latency levels over time, caused by actions like queuing and routing that affect the path of packets as they travel through the network. A congested network will generally have higher levels of jitter, but proper quality of service controls like queuing and bandwidth allocation can control the problem.

Delay/Latency

Exceeding the acceptable delay/latency levels for a voice application can make for a voice call in which parties are forced to pause each time they speak and wait for the other party to hear what they’ve said. For video and IPTV applications, likely impairments can include “freezed” frames and corrupted images displayed on monitors and TVs.

These problems can be solved by quality of service measures that monitor and buffer packets as they travel across the network, ensuring that they are transmitted with acceptable amounts of delay and in the proper order.

Voice Echo

In a hybrid network, analog phones can be the source of echo, but a pure IP telephony configuration is also susceptible, since some calls will inevitably interface with TOM network elements at some point when they go “off net.” Voice echo occurs when participants can hear their own voices coming out of a phone’s ear-piece, and if extreme, can make a voice call completely intolerable.

Clipping

Clipping within VoIP calls occurs when either the beginning or end of words, or whole words, seem to be cut off during a conversation. This can occur when voice activity detectors and other solutions that work in tandem with echo cancellers are thrown out of sync. 

Enabling New Features and Services

Perhaps the greatest benefit of the triple-play for telcos is the ability for them to provide a host of new enhanced services and applications that would have been impossible for them to offer before, over their relatively low speed, inflexible legacy network infrastructures. Not only will a true IP triple-play allow telcos to enter the entertainment marketplace with video on-demand and IPTV, but the integration and bandwidth improvements will also help facilitate and promote a host of new and unique services, including video phone and video mall, e-learning, medical alerts, and SMS alerts on mobile devices of incoming calls to the home phone.

Conclusion

In the end, the quality of the user experience is the factor that will ultimately determine whether a telco’s efforts will succeed or not. And in order for a provider to offer a world-class user experience, the operation of triple-play applications, services and underlying infrastructure must be effectively managed for optimal performance.

Source: http://cablequest.org/articles/broadcast-technology/item/1299-triple-play.htmlSource: http://cablequest.org/articles/broadcast-technology/item/1299-triple-play.html