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Managing Cable TV Migration to IP – Part 1 Series Introduction: Market Drivers and Tech Challenges Architectural Alternatives for CableIP Converged Services Consumer Premises Equipment Jeff Brooks, VP – IP Video Product Management, 678-473-8395, jeff.brooks@arrisi.com Carol Ansley - Senior Director, IP Engineering, 678-473-8630, carol.ansley@arrisi.com Dan Torbet – Director Media Technology and Architecture Strategy, 720-895-7130, dan.torbet@arrisi.com 3871 Lakefield Drive Suwanee, GA 30024 2 Contents 1 Introduction 3 1.1 Subscriber and Service Expectations 3 1.2 Defining and Segmenting the Requirements 4 2 Advanced Digital Cable Gateway Network Side Interfaces Requirements 5 2.2 Basic Assumptions 5 2.2 Required Gateway Network-side Interfaces 6 2.3 Network-Side Interface Capacity 8 2.4 Network-Side Interface Control 9 2.5 Alternatives and Strategies for Addressing Network-Side Interface Requirements 11 3 Subscriber Side Network Interfaces 11 3.1 Subscriber Side Direct Video interfaces 11 3.2 Subscriber Side Home Networking Interfaces 12 3.3 Subscriber Network Logical and Control Interfaces 14 4 Content Protection 15 5 Service Provisioning, Tracking and Billing 17 6 Device Control and Monitoring 18 7 Gateway Configuration Options 18 8 User Interface 20 9 Advanced Features 20 10 Conclusions 22 References 23 Recognition 23 Key Search Words 23 List of Acronyms 24 3 1 Introduction Many Multiple System Operators (MSOs) are faced with competitive and financial pressures to enhance the subscribers’ total in-home video and communications experience. The Cable Industry is focused on Internet Protocol (IP) as a tool to help meet these needs. Voice and Data are already IP-based, leaving Video as the last service silo to converge to Internet Protocols. New subscriber expectations and rapid technology shifts create a myriad of alternatives for network termination. These ―end point‖ alternatives combined with the current state of an operator’s network drive multiple alternatives for the transition from today’s consumer premise equipment to future converged service IP-based network termination devices. This paper will examine the requirements, alternatives and strategies associated with network termination CPE (Consumer Premise Equipment) in a transitional network and an all IP network. Areas of analysis will include; network side interface(s), content protection, device and service provisioning and control and monitoring, and subscriber side interface(s). A proposed method for evaluating the alternatives will include qualitative and quantitative aspects. 1.1 Subscriber and Service Expectations From a subscriber’s point of view, the method of delivering these signals is less important than several other attributes, including: The ability to route video signals around the home IP network to any IP- enabled endpoint The availability of bandwidth or network capacity that permits them to access all of the video content that they want at any point in time The Quality of Service (QoS) mechanisms to ensure video content is delivered reliably without pixilation or halts (which can only be guaranteed for On-Net IP Video delivery services) The availability of large quantities of high-quality video content, both popular and long tail The ability to perform trick modes (pause, rewind, and fast-forward) on the viewed video content These attributes can be summed up as: The ability to consistently access all video content at any time and in any format required by any desired endpoint device 4 The subscriber is also interested in communications services such as high speed data and voice. History has proven subscribers are less likely to churn when they purchase a video, voice, and data bundle from a single service provider. Thus, we should consider the delivery of all three services to the home. Since operators are already faced with competitive pressures this paper will concentrate on meeting the near-term service requirements within existing network, technology, and financial constraints, without limiting the operators’ ability to achieve the end state of an all IP network. 1.2 Defining and Segmenting the Requirements The CPE is at the center of the complex intersection of the operators’ networks and the subscribers’ networks. It has traditionally provided functional requirements layered on to the service provider (SP) by content owner, and regulatory bodies, as well as the myriad requirements associated with the SP and consumer networks, services, provisioning and management. In addition to the basic requirements, factors such as cost, time domain of an implementation, technology maturity, and operational impacts can further complicate the CPE device and its engineering and planning, installation and management processes. The next section of this paper will attempt to identify requirements for the major sub-systems of a CPE device capable of delivering video, voice and data services from a Cable TV network. Cable Labs Multimedia Gateway Device Architecture Technical Report CL-TR- GW-ARCH-D02-110114 defines CPE that deliver, entertainment video services (linear and on-demand) to home networked devices using IP, high-speed data service, and telephony service as a gateway. The report further defines three specific types of gateways. Video Gateway (V-GW): The video gateway can be considered as an evolution of the digital video set-top box. From the data plane perspective, it tunes to MPEG2 transport streams delivered via QAM, terminates the RF, demultiplexes individual programs, terminates the Conditional Access, performs certain manipulations on the content (possibly transcoding and/or encrypting), encapsulates the resulting program as a single program transport stream in IP, and delivers it to a client device via the home network. Data Gateway (D-GW): The data gateway enables the delivery of Advanced Digital Cable video services to IP clients via an ―end-to-end‖ IP approach, utilizing DOCSIS 3.0 technology for access network delivery of video content. Split Data Gateway (Split D-GW): The split data gateway is an alternative implementation of the data gateway in which the cable-network-specific functionality is packaged separately from the home network functionality. The result is an in-home router device (―In Prem Router‖), and an HFC termination 5 device (or ―Network Interface Unit‖ (NIU)) that will be environmentally hardened for exterior mounting, or will be designed for interior mounting such as in an MDU application. [1] Throughout the Technical report, CableLabs defined a device that is ―headless‖ as the gateway contains no direct video output to a viewing device like a television. We will adopt the ―Gateway‖ terminology in this paper to differentiate this CPE device from a simple set top box or cable modem. We will further address gateway configurations later in this document. However, we should at least establish the definition of a headed gateway versus a headless gateway. Headed Gateways include video rendering and at least one output connection (RF, Component, Composite, HDMI) to a TV. A headed gateway must also support connections to additional devices such as a smartTV, game system, or IP Set Top Box to display video; else it would simply be an advanced set top box. Headless Gateways do not include video rendering. Headless gateways must be used in conjunction with an additional device such as a smartTV, game system, or IP Set Top Box to display video. 2 Advanced Digital Cable Gateway Network Side Interfaces Requirements 2.2 Basic Assumptions We must start with some basic assumptions prior to defining the network side interfaces. These assumptions may be operator dependent or time dependent. However, our intent is to make these relevant to a significant portion of the existing MSO service delivery networks at the time of this writing. A coax ( RG-6/F connector ) connection is available at the home No fiber connection is available to the home A significant portion of the HFC spectrum is used for delivery of ATSC/DVB video and DOCSIS® data Figure 1: Typical Spectrum Allocation 6 - The spectrum assigned for advanced services such as VOD, SDV, HSD has been well engineered and runs at approximately 85% capacity during planned peak usage. i.e. There is little spectrum available for additional services. 2.2 Required Gateway Network-side Interfaces To enable a smooth transition we should also establish a model system for the examples through this paper. This model is not to imply these are fixed factors. They are simply useful for our example calculations. The Cable Network termination device at the home will be required to address the spectral and channel assignments for each of the ANNEX’s and the optional DOCSIS upstream splits. Table 1: White Paper Modeling Variables Model Variables Upstream split 5-45 MHz Downstream 52-750 MHz Channel width 6 MHz # Downstream Channels 116 DOCSIS Downstreams 8 Analog Channels 70 Digital Broadcast SD 65 Digital Broadcast HD 30 Switched Digital SD 300 Switched Digital HD 170 7 Now that we have a baseline for the network, we can look at the interface requirements on the device itself. Let’s first look at the various Transport protocols used to deliver services. There are two basic transport methods; QAM (aka MPEG- TS) and DOCSIS. Each of these can carry multiple services depending on the Control Plane applied. For example, QAM delivery typically carries Digital Video, Switched Digital Video, On- Demand and other services over RF. While the DOCSIS transport may carry data, voice, control messages such as DSG, and/or video over IP and DOCSIS. To enable a smooth transition that can begin immediately, a new Gateway should support existing network transport interfaces, specifically, QAM based MPEG-TS video and DOCSIS data. The QAM interface allows the Gateway to take advantage of all services currently being provided by the operator’s HFC network, such as Broadcast video, Switched digital video, Pay per view and Video on Demand, without imposing any extra burden on the HFC network. A DOCSIS interface is mandatory to both provide high speed internet access and telephony services as well as to provide a transport pathway for advanced video services over IP. The current state of the art in DOCSIS cable modems supports the use of up to 8 channels of DOCSIS3.0 bonded downstream capacity and up to 4 channels of DOCSIS3.0 bonded upstream capacity. While most HFC networks do not have that many DOCSIS DS and US channels in place at this time, intelligent planning for IP video requires that the number of channels devoted to DOCSIS steadily increase in the coming years. Figure 2 below summarizes the potential major service inputs from the network to a Gateway. Figure 2: Network Service Inputs to a Gateway 8 2.3 Network-Side Interface Capacity Let’s first evaluate the QAM receiver capacity requirements of a gateway device. The gateway will receive and distribute all signals into the home. Therefore the Gateway will be required to address all of the video needs within the home. This means it must be able to ingest all unique programs to each TV and all unique programs to be recorded. The average number of TVs in a U.S. home today is greater than two, or rounded up to three. It is also not uncommon to record a show while watching another. Therefore let us assume the minimum number of QAM tuners required is 4. We also know from subscriber research that more is better in this category.[2] Therefore the question of how many more than 4 QAM tuners to include on the network side becomes one of subscriber satisfaction regarding the number of simultaneous programs they can consume. This should also be balanced against the cost of the additional tuner in all gateways vs. the added gateway in some portion of subscriber homes. DOCSIS Capacity required will be a function of multiple variables. These include the encoding density of the content (Variable Bit Rate versus Constant Bit Rate), the number of streams to be consumed in each home, the service group size associated with the bonded group, unicast or multicast delivery of Linear and VOD content. The traffic engineering graphs Figure 3 and 4 were developed using the above variables along with traffic engineering data collected from major U.S. Cable operators to assist in the sizing of service groups and bonding groups for IP Video deployments.[3] Figure 3: Video Streams Based on Active Users and On Demand (unicast) Ratio 9 Figure 4 indicates the minimum quantity of DOCSIS channels to be used for a gateway is sixteen (16). This would require there be fewer than 75 active users behind all gateways in the node. An active user would be defined as a TV or DVR rendering or recording content. This does not include DOCSIS bandwidth to be used for high speed data and voice services. These services would increase the required number of channels. It should also be noted that as the number of active users increases (i.e. the node size increases) the number of DOCSIS downstreams required to meet the video service requirements increases. 2.4 Network-Side Interface Control Aside from the physical layer of network interfaces, we must also consider the higher layer control interfaces that are required to make full use of these interfaces. For a Gateway to optionally support the current video services, interactions with several different control planes are required. The current set top box management systems in the cable headend operating through DSG or OOB will need to communicate with the Gateway to handle channel changes and ordering of services. If the Gateway also provides IP video to subtending IP STBs or connected TVs or the like, then the gateway may also need to translate between the headend management systems and the other local IPCPE devices. These interactions may also include network-side communications for CableCard (or firmware based Conditional Access) support. Gateways may also need to support the control plane interfaces described in OCAP specifications for STB user interface functionality. In European and other world markets, the DVB specification must be followed. Figure 4: Video Access Blocking Probability as a Function of Active Users and DOCSIS Channels 10 For many video specific services, such as Video on Demand (VOD), Pay per View (PPV) and Network DVR, there are no standardized interfaces, and a Gateway must integrate support for each specific combination of suppliers to provide service. Most progressive vendors of video specific services have moved to IP messaging for their network-side control plane, but some vendors have not. In some cases, the operator may be faced with retiring older equipment that works with their installed base, but cannot be upgraded to support IP-based devices. Switched Digital Video control interfaces have been standardized to a great extent. The integration of an IP-based Gateway with these systems can be accomplished allowing the operator to potentially use SDV to free DS channels up from video use for DOCSIS use. For new IP-based video services, a control plane will still be needed to manage the CPE devices, authenticate and authorize them for video services as well as other uses. The same functionality that exists in the QAM control plane must be present in the IP video delivery system. An IP-based network side control plane will utilize the DOCSIS network, but there are again choices to be evaluated. An all-IP network will probably have to provide broadcast and unicast services to the end users, similar to today’s network. Bandwidth studies have found that migration to an all unicast network is not practical without significant reduction in the average HFC node size in use today. The all-IP network’s control plane will probably also be required to interface into today’s billing and provisioning systems. For the Gateway’s network side interfaces, that probably means increased security requirements. Today most traffic on the DOCSIS network does not require encryption aside from privacy concerns, future networks may impose stricter requirements to ensure that high-value video content is protected. Figure 5 summarizes the major network side control plane interfaces required for a transitional gateway device. Figure 5: High Level Gateway Network-Side Interfaces [...]... Network a distributed set of servers and software used to storage content close to it point of consumption CM Cable modem connects a computer or local network to broadband Internet service through the same cable that supplies cable television service CPE Customer Premises Equipment Communications equipment that resides in the customer's premises DECT Digital Enhanced Cordless Telecommunications cordless... normally terminate the CAS with an internal CableCard Then the gateway must reformat the video stream for transmission over a home network to the IP STB 14 For a video stream delivered using an all -IP delivery method, the IP STB may be communicating with the headend video network directly to request Gateway strictly forwarding the incoming data directly to the IP STB In the first example, the Gateway... second architecture requires that those services be instantiated within the headend, or further back in the content distribution network which again causes a greater startup burden to provide the same basic services as today in a new IP video architecture Even assuming that a subtending IP video device has a reliable home networking connection to the Gateway, we should also consider how that IP Video... References [1] CableLabs Multimedia Gateway Device Architecture Technical Report CL-TRGW -ARCH- D02-110114 Draft [2] ARRIS/Bend Subscriber research regarding ALPHA Service with ARRIS Moxi deployment [3] Major US MSO usage data Recognition The authors of this document would like to thank Tom Cloonan, Debbie Stackis, Ron Miller, Kevin Neely, and Steve Gunn for their input and contributions Key Search Words... must also consider the logical networking alternatives Most of the current devices cooperatively provide services In the IP realm, that paradigm can change For video delivery to a subtending IP STB, a Gateway may be a key player, or it may be a mere conduit through which the content passes depending upon decisions made about the desired end architecture of the IP video network Consider two examples from... operator must address is the control plane for the new IP- based video delivery The current IP Video deployments in both the TV everywhere and the Telco IPTV markets are highly dependent on the supplier Thus the gateway must be flexible enough to be integrated with each supplier until the industry develops standards for the gateway interface to the IP video control plane 3 Subscriber Side Network Interfaces... been given the transport network challenges for IP Video conversion over the past 2 years Due to the enormous potential impact that the next-generation CPE sub-systems may have on operator spending and network complexity, operators would undoubtedly benefit from similar (or greater) amounts of attention being dedicated to the CPEs that will be used in their IP Video conversion It is widely known that the... data connection, usually to the Internet IP Internet Protocol - a communications method for transmitting data over a network a DRM system used for Large capacity storage media the distribution network used by CATV 25 a standard for data networking IP STB Internet Protocol Set Top Box a set top box configured to receive its video over an IP connection MDU Multiple Dwelling Unit MoCA Multimedia Over Coax... interworking devices and servers will require careful management 4 Content Protection The need for content protection does not change with the transition from MPEG to IP, although the methods used to accomplish content protection will change The current cable video distribution systems rely on the use of a two tier encryption process, commonly referred to as a Conditional Access System (CAS) The content is encrypted... the IP connection may be of a very different format than the delivery over the QAM infrastructure Because a new scheme will be required to monitor video delivered over the IP infrastructure, operators should seriously consider applying these tools to monitor the device itself and the video received over the QAM infrastructure There is an additional nuance that must be considered with a Gateway architecture . Managing Cable TV Migration to IP – Part 1 Series Introduction: Market Drivers and Tech Challenges Architectural Alternatives for Cable IP Converged Services Consumer Premises Equipment Jeff. video, voice and data services from a Cable TV network. Cable Labs Multimedia Gateway Device Architecture Technical Report CL-TR- GW -ARCH- D02-110114 defines CPE that deliver, entertainment video. premise equipment to future converged service IP- based network termination devices. This paper will examine the requirements, alternatives and strategies associated with network termination CPE (Consumer