The secrets to a successfully IPTV deployment Copywrite © Stephen Davies ([email protected])

Abstract In the industrialised world, there are 492 TV sets per 1,000 people, compared with 59 per 1,000 in developing countries. In the USA where 75% of households have two or more TVs, this figure grows to 814 per 1,000. Daily per capita viewing is more than 4 hours for adults and 6 hours for children. However the world’s viewing habits are changing. According to Stanford Institute for Quantitative Study of Society (SIQSS) the traditional viewing of network television programs by sitting in the lounge room is decreasing. What is increasing is the use of home theatre, multimedia entertainment and computer based television where the viewer can determine what they watch and when they want to watch it. From this demand for new multimedia entertainment we have seen the rise of IPTV. Keywords FTTH, Broadband, IPTV, Fibre, EPON, GPON, BPON Introduction As the world and its people continue to move faster our leisure time is being eroded. Television viewers want to watch their selected programs at their convenience rather than times dictated to by the networks and their advertising income. Basically they want more CONTROL. So what has changed that is enabling users to have more control over their television viewing habits? It’s called “true broadband”. For many years we have talked about broadband and the benefits it brings to the community, both economically and socially. True Broadband is delivered over networks that support a minimum of 10Mbps to the home thus providing a vastly greater array of advanced multimedia services. Four Generations of TV One such multimedia service which has created the forth generation of television is IPTV. What are the four generations of television? • • • •

1939 Black and White television was displayed at the World Fair in New York 1954 RCA commercially released the first Colour Television 1997 DTV broadcasting beings 2000/01 IPTV is launched

So what is the difference between IPTV and broadcast or pay TV? In a word CONTROL. IPTV being based on a two way protocol (IP) enables the end user device to be more interactive, that is the user has greater influence over the programmes, timing and content. IPTV is the engine that will drive the new era of “interactive content”. Being ahead of the game with the new technologies, new content formats and new business models that IPTV

ushers in will determine the success or failure of telecommunication operators in the coming years. Video is the Driver For several years I have heard the statement “Video is the driver” for any broadband network deployment. Interesting while this may apply in the US where PayTV has a take up rate of more than 80%, in other counties such as Australia (where I am from) and many European states, PayTV has a comparatively low take up rate. However, if PayTV services in the US are already delivered via HFC or Satellite, why are companies like SBC and Verizon pushing ahead to build new FTTx networks costing billions of dollars. Can they even afford this? The answer is simple. HFC and Satellite networks lack control. They cannot deliver the advanced interactive and multimedia services which are features of IPTV. Only FTTH networks can provide the capacity and capability to support this type of functionality. It comes back to my original statement that people’s TV viewing habits are changing and they need more CONTROL. IPTV provides that control. Case Studies In Australia there are two companies that I provide design and engineering consulting. Bright Telecommunications has been world leading in the delivery of commercial IPTV services. Forming in 1999 as a trial project under the state government owned Power Company; they began delivery of commercial IPTV services in 2001, at a time when there was limited support from vendors and particularly STB manufacturers. Bright originally deployed FTTN and then Active Ethernet technology, but soon realised a specialised solution was required to provide the types of services that were emerging. In 2003 Bright deployed a GEPON solution which has been highly successful. The company focuses on residential overbuilds and business services. IPTV has proven to be very popular even for the business market. In Perth one of the major problems for downtown is TV reception, so many businesses have taken up the IPTV service, as their product array includes services and content that is suited to the business market. BES is a more recent adopter of IPTV. They began 8 years ago by rolling out HFC networks in Greenfield estates, delivering analogue TV signals via the RF medium. However in 2004 BES found developers were becoming more IT savvy and were asking about fibre and particularly on demand services such as VOD. This meant they needed a change of technology and in early 2005 they also selected a GEPON solution. BES has used the solution effectively, delivering a mix of both RF and IPTV solutions. Their service line up also includes Video on Demand and most recently WebTV which has been welcomed by many of their senior customers. Since then BES have signed agreements with developers that has them contracted to deliver FTTH and IPTV services to more than 50,000 new home sites. Deploying IPTV So IPTV is easy right – it must be its IP! IPTV is definitely not easy; at least it is no more difficult than the vagaries of RF networks. However, in 6 years of working with vendors from core to access and onto CPE, not one vendor started with a correctly working IPTV solution. My early involvement with many vendors (Alloptic, Amino, Start, Allied Telesyn, Alcatel, Ericsson, Enterasys, Cisco, and Marconi to name a few) has helped to resolve many of their

issues to now have workable solutions. Some did it better than others, others still today don’t understand what is needed. IPTV operates at multiple layers, and you need to ensure that each layer is working correctly, otherwise your service quality and functionality will suffer. There are five main areas to ensure your IPTV network is well built.

These areas include: • • • • •

Headend Core Transport Access Home

Let’s start with the headend. Here you need to ensure you have receivers, encoders, transcoders and streamers. A receiver could be as cheap and simple as your standard Satellite or Cable STB, but these take a single digital DVB channel and output an RF analogue signal which then needs to be digitised again. A better way is to use studio grade DVB receivers such as Tandberg or Minvera. These take the RF L-Band signal in and output a multi channel DVB-ASI. This in turn is connected to either a transcoder or streamer.

Hint #1 – The Headend Try to use quality DVB equipment such as Tandberg or Minerva receivers and streamers as this puts you off to a good start. Use high performance routers and switches. While Cisco can deliver the performance it is at a high price. Consider looking at the ASIC based devices like Foundry or Extreme. They have a much higher performance for a much lower price. Prioritise your IPTV traffic over the transport network. Over dimensioning does not give Quality of Service.

The stream does the job of selecting one of the multi channel DVB streams from the DVB-ASI and wrapping the DVB stream with a multicast IP address and then outputting this stream to the core router via an Ethernet port. The streamer does nothing to the DVB stream but pass it through. A transcoder however will take in the DVB stream and re-encode the MPEG-2 at a different bit rate before delivering to the streamer. An encoder takes an analogue signal and turns it into an MPEG-2 stream.

The core router takes in the various different content inputs such as VoD, Internet, VoIP as well as the Multicast IP traffic from the streamer. To effectively manage this traffic and prevent a broadcast storm, the router must be configured with a multicast management protocol such as PIM or DVMRP. IGMP is a multicast management protocol for layer 2 networks whereas PIM or DVMRP are multicast routing protocols for layer 3 networks. We talk more about IGMP later. The router must also be fast enough to support the required bit rates that IPTV services will generate. 50 Channels of Standard Definition IPTV will generate about 250Mbps of traffic. Add in your mix of SD and HD and you could be looking at 300-400Mbps. If you are thinking Cisco this means at least a 7200-NPE-G1. At Bright, they use Foundry Networks, technology as good as Cisco, but much, much cheaper. Why do you need a multicast management protocol? While there is a big difference between a multicast packet and a broadcast packet, to a layer 2 or 3 network which is not multicast aware they both look the same. Streaming 50 channels of multicast traffic into a non multicast aware network will create a packet storm from which your network would not recover. Using PIM or DVMRP performs two things, it manages the multicast packets to ensure they don’t become broadcasts, but it also provides an affective mechanism for bandwidth management. In a digital multicast world, only the channels that are required need to be streamed. If no-one is watching a particular channel then don’t stream that channel. PIM and DVMRP perform this function admirably, reducing the traffic burden on the transport network. Down at the hub site, we have a multi-layer switch. This is where the layer-3 domain ends and the layer-2 domain (the access network) begins. The multi-layer switch needs to support PIM or DVMRP to manage the pruning of unused multicast streams. It then interfaces into your selected access network. The access network should be layer-2 (only) and needs to support IGMP version 2. Moving closer to a customer, your solution should provide IGMP snooping within the home CPE. There are two methods of implementing IGMP, snooping and proxy. Snooping is just that, it monitors for IGMP requests, performs the multicast stream management and passes the request through. Proxy on the other hand is much more advanced and provides a higher level of security and improved performance in the management of multicast streams. Capacity Planning Capacity Planning is important in any network but particularly IPTV. Don’t fall into the trap of throwing Gigabit interfaces at any problem. Plan out the network first and consider the following: • •

•

Internet: How many concurrent users? What is their utilization? What is their access speed etc? Telephony: Does it need prioritization? What codec is being used? What is the average busy hour? ERLANG theorems. Television: How many channels? What is their bit rate? Multicast

Hint #2 – MPEG2 Bit Rates You will see many presentations that show Standard Definition MPEG-2 streaming at 3.5Mbps. Typically these are the ones espousing IPTV working over ADSL2+. In addition you need to add a further 3% for IP overhead and another 15-25% for ATM (aka ADSL2+) networks. In effect 3.5Mbps of bandwidth would support only a 2.4Mbps video stream with 384Kbps audio. Try displaying this on a medium sized plasma or LCD screen and the quality is awful. The reality is that SD streams typically are at 5 or 6 Mbps and higher for sports channels or during sports broadcasts. HD streams are about 10Mbps and sometimes 15Mbps.

control protocols. Pruning. These issues can affect the performance and design of your network, but so to does the technology that you select within your headend and hub sites. While no one ever gets fired for buying Cisco, this is not an automatic choice when it comes to high speed networks, particularly ones which support IPTV. Your capacity planning will help to find out what is the right routing and switching technology to meet the performance needs of your IPTV enabled network. Access Network The access network is the most important part of your IPTV network. Get the wrong solution and you will have major problems, because IPTV is a very finicky application (and so are the users). The internet can be flaky, the phones may not work properly, but heaven help you if your TV service doesn’t work (particularly during prime time). Users expect their TV to work 100% of the time in perfect quality and without glitches, and if it doesn’t expect a lynch mob banging on your front door. Get the right access equipment and you can have a trouble free IPTV service. Hint #3 – Multicast IP Support Don’t be fooled into believing every access or core routing solution supports IPTV. There are two types of IPTV: • •

Unicast IPTV which is used for On Demand services and supports a single stream for a single user; and Multicast IPTV which is used for Broadcast streams such as your standard PayTV and Free to Air TV channels.

While most solutions will support Unicast IPTV, many don’t support Multicast TV. So make sure you ask the right questions, does your access vendor support multicast IPTV and do they support as a minimum IGMP version 2.

Take the BPON access solutions. These are ATM based and were never designed to support IP Multicast. While they happily carry On Demand services such as VOD, they do not support the multicasting of TV channels. This is one of the reasons why I can never understand why the RBOCs went down the BPON path. They basically locked themselves out of provided IPTV services to their clients. In affect they deployed a brand new network costing billions of dollars that delivered services no better than the existing HFC cable solutions. Now they are doing the same thing again, by issuing a tender only for GPON technology. GPON currently has no deployed IPTV networks, is yet to be commercially available and the technology from the vendors I have seen has a fundamental flaw – a single Ethernet port on the ONT. I go into

that issue later. An access network needs to support the Internet Group Management Protocol version 2 (IGMPv2). Without this it is impractical to deliver IPTV because the multicast packets entering the access hub will be transmitted across the entire layer 2 network, creating what is called an IPTV broadcast storm. How IGMP is implement is also important, as it can impact on the performance of channel change times. A long delay will frustrate users trying to channel surf, thus diminishing their experience and their views on your product. IGMP should be implemented across the OLT back-plane using a mechanism called IGMP proxy. This mechanism means the OLT will proxy all requests from the STBs and present its own requests upstream. This has two benefits: a) it improves the performance of channel change times; and b) it reduces the processing load on the upstream multi-layer switch.

However it doesn’t end there In the Home As indicated earlier, homes typically have more than one television; in fact frequently have two or even three. Mostly these televisions are being watched by different people with different viewing habits and tastes. Therefore it is reasonable to assume that different channels will be streaming into the home to different STBs. If you use a standard layer-2 switched network within the home, the multicast packets will become broadcast packets and a packet storm begins. While it may seem three 5Mbps streams on a 100Mbps network won’t cause too much trouble; the reality is STBs have limited processing power and cannot handle anything more than 8 or 9 Mbps for a SDTV box. Three streams totalling 15Mbps being broadcast to all boxes will cause distortion of the signal being displayed on the TV. Furthermore I have frequently seen it cause problems with essential internet protocols such as DHCP and PPPoE. To work properly within the home a multi-port ONU should be used providing a dedicated IGMP managed Ethernet port to each STB. This offers two benefits: a) it eliminates broadcast storms within the home; and b) it improves channel change times. Combining the use of IGMP proxy at the OLT and the ONU delivers a more robust multi layered IGMP implementation ensuring a better user experience. Conclusion IPTV is a method of delivering new and more advanced interactive television services into the home. It enables the service provider to differentiate themselves from existing satellite and cable companies, and at the same time increase their revenues and reduce churn. To wrap up, here are my Top Ten tips for a successful deployment of IGMP. Top Ten Tips for a Successful Deployment 1.

Forget about BPON does not support IPTV

2.

Forget about GPON unproven with IPTV

3.

Use a proven Access provider with existing IPTV deployments

4.

Beware of the bandwidth requirements of your IP multicast streams

5.

Select routing/switching technology that supports IPTV

6.

Use multi-port ONUs. RGs are expensive & troublesome

7.

Pick a good STB vendor with proven IPTV experience

8.

Ensure you CA, DRM, Middleware and STB work together

9.

Carefully consider the issues before developing your own middleware

10. Get people with proven IPTV experience to implement

About the Author Stephen Davies is an experience ICT engineer and consultant with over 22 years specializing in the design of data and telecommunications networks. A former CEO of Atlas Global Net, a telecommunications service provider with a large regional Western Australia network, he has extensive network design, commercial and strategic planning experience at companies that included Westnet, Comswest, Optus, Amcom, Silk, Bright Telecommunications, FuzeConnect, Opticomm, among others. Over the last 10 years he has been actively involved in the establishment of the Fibre to the Premises industry in Australia and New Zealand. He regards himself as Australia's leading expert on Fibre to the Home with involvement in more than 30 projects throughout Australia, New Zealand and Bahrain and consulting to four of the seven FTTP carrier service providers in Australia. Mr Davies is a member of the FTTH Council AsiaPac and the Chair of the Brownfields and participant in the Greenfields working groups within the FTTH Special Interest Group. He a is regular speaker at domestic and international conferences, having more than 100 presentations over the past 10 years on subjects such as FTTP, IPTV, Gigabit Ethernet, SDH, Service Level Agreements, and Satellite communications to name but a few. Stephen can be contacted on (+61 4 1998 7716) or via email [email protected]

Disclaimer The author does not represent himself as competent professional except for the planning, design and implementation of Telecommunications and Information Technology systems, networks and practice. Any statement provided which may be of a legal nature is only offered as an opinion based on the author’s understanding of the law and how it may apply. The author has made every effort to identify all relevant and available source data in the preparation of this document. All surveys, forecasts, projections and recommendations are made in good faith on the basis of information available at the time. The author, its agents, licensee and/or other representatives disclaims any liability for loss of damage caused by errors or omissions, whether such errors or omissions resulted from negligence, accident or other causes. Neither the author, its agents, licensee nor representatives will be liable for any loss or other consequences (whether or not due to the negligence of the author or their agents) arising out of the use of information in this report. No responsibility is taken for the accuracy of this information in relation to pricing or functionality of products and services described in this report. Readers should confirm with the appropriate service provider as to the validity of the information and any variations which may have taken place since publishing

Acronyms

1080i

High Definition Digital Television

480p

Standard Definition Digital Television

ASI

Asynchronous Serial Interface (DVB-ASI)

ASIC

Application Specific Integrated Circuit

ATM

Asynchronous Transfer Mode

BPON

Broadband Passive Optical Network (ITU G.983)

CA

Conditional Access

DRM

Digital Rights Management

DTV

Digital Television

DVB

Digital Video Broadcast

DVMRP

Distance Vector Multicast Routing Protocol

FTTH

Fibre to the Home

FTTN

Fibre to the Node

GEPON

Gigabit Ethernet Passive Optical Network (IEEE 802.3ah)

GPON

Gigabit Passive Optical Network (ITU G.984)

HD

High Definition (more correctly HDTV)

HFC

Hybrid Fibre Coax

IGMP

Internet Group Management Protocol (RFC 2236)

IPTV

Internet Protocol Television

MPEG

Motion Picture Experts Group

OLT

Optical Line Termination

ONT

Optical Network Termination (BPON/GPON CPE)

ONU

Optical Network Unit (GEPON CPE)

PIM-DM

Protocol Independent Multicast – Dense mode (RFC 3973)

RG

Residential Gateway

SD

Standard Definition (more correct definition SDTV)

STB

Set Top Box

VoD

Video on Demand

WebTV

Internet Browsing from the TV