Internet Access- All About Services

Definition and Overview

Definition

Internet service is expanding rapidly. The demands it has placed upon the public network, especially the access network, are great. However, technological advances promise big increases in access speeds, enabling public networks to play a major role in delivering new and improved telecommunications services and applications to consumers.
Overview

In today's environment, twisted-pair access using voiceband data modems is the norm for residential and small business users. With new technologies, speeds of 500 kbps, 1.5 Mbps, or even 10 Mbps are promised for residential users.
How will access systems evolve to provide such capabilities ubiquitously? This tutorial describes existing and emerging access technologies used to provide Internet access for residential and business applications.

Where Is Access in the Network?

Internet access has different meanings to different people. In this section, the concept of access will be explained for consistency within this tutorial.

Figure 1 delineates three major entities in the provision of Internet service:

• end users who want to have Internet service as well as other services, such as telephony or cable TV
• data service providers who want to supply Internet access, content services (like AOL), or other data services, such as virtual private networking
• telephony, wireless, and cable service providers who want to provide connectivity between end users and data-service providers

Figure 1. Network Model

Note that, at times, the last two entities are combined. For example, several companies such as MCI, AT&T, or Pacific Bell provide both telephony and Internet access.
Now to the question: "What is access?" To the telephony, wireless, or cable service provider, access is the network connection from the end user's home or business to the outside-plant termination point within the service node. In traditional telephony architecture, this is most commonly thought of as the twisted-pair, cross-connect point and is referred to as the main distribution frame (MDF). The remainder of the telephony's provider's network would be referred to as the switching and transport network.
In contradistinction, an Internet service provider (ISP) views access as the connection from its customer to its network. Here, access is the connection from the end-user's home or business to the gateway-access node belonging to the ISP. Thus to the ISP, the telephony's access, switching, and transport network is all part of access.
Within this tutorial, the telephony, wireless, and cable service provider's view of access is the focus of our discussion of new and emerging technologies.

Access Evolution Drivers

Access evolution is being driven primarily by strong demands for increasing bandwidth to support a growing variety of user services. Prior to 1994, traffic sent over the Internet was largely text-based information with file transfer and e-mail being among the most popular services. The surge in growth of the Internet during 1995 was in part due to the graphical nature of the World Wide Web (WWW). A significant aspect of this shift is that graphical images generally consist of a large number of bits. To transfer large graphical image files quickly with satisfactory performance meant that higher-speed access technologies were needed than those used to deliver relatively small text files. The WWW also became the base for nurturing other capabilities such as animated graphics, audio, and low-rate video. Each of these capabilities have been pushing the need for increasingly higher-speed access.
Figure 2 is an example of the data rates needed to support various user services and the access rates that have become available over time. (The chart represents average user rates, not peak burst rates on shared media.) The chart shows curves for three segments of the user population: the median, the upper twentieth percentile, and the upper second percentile early adopters. Users are eager for audio and video services, so the challenge is for access systems to meet that demand.

Figure 2. Internet Access Rate Growth

An Overview of Access Alternatives

Internet-access technologies fit into four broad categories:

• twisted pair
• fiber/coax
• wireless
• all fiber

As shown in Figure 3, several technologies and implementations exist within each of these broad categories.

Figure 3. Access Alternatives

Twisted-pair telephone lines are the access media used by the vast majority of individual residential subscribers today. Over time, a number of technologies have been introduced to provide faster data speeds over this medium.
Fiber/coax systems were originally introduced for video-broadcast applications. Because these systems are inherently broadband, techniques have been developed to use this advantage to provide high-speed data transmission, principally for residential Internet access.
Wireless Internet access has two origins: satellite systems established for broadcast video have the ability to distribute Internet data at high speeds, and cellular/personal communications service (PCS) systems are designed to serve mobile users.
The predominant access systems for business users are optical-fiber synchronous optical network (SONET) and synchronous digital hierarchy (SDH) systems. In the future, passive optical network (PON) systems are expected to become an all-fiber access medium for residential users as well.

Twisted-Pair Solutions

There are three major categories of twisted-pair solutions that are being used for Internet access (see Figure 4):

• voiceband data (VBD) modems
• ISDN digital subscriber line (DSL)
• other DSL approaches (xDSL)

Figure 4. VBD and ISDN

VBD modems are well known and understood by residential and small-business users. They operate by using the voice-frequency band of the twisted-pair facility to transmit data, using frequency shift keying (FSK) or quadrature amplitude modulation (QAM) transmission techniques. Symmetric rates exist up to 33.6 kbps, with the majority running at 14.4 and 28.8 kbps. Emerging is an asymmetric capability with a nominal server rate of 56 kbps and return-path rate operating up to 33.6 kbps.
Integrated services digital network (ISDN) is a digital baseband technology that operates with a 144–kbps bidirectional payload rate using 2B1Q encoding scheme. The 144–kbps rate is divided into two 64–kbps (B) channels and one 16–kbps (D) channel. The B channels can be used for two separate voice calls, two 64–kbps data calls, a separate voice and data call, or a combined 128–kbps data call. The wire limit for ISDN is 18,000 feet on standard twisted pair.

xDSL Technologies
A variety of xDSL rates and technologies have been standardized, or are in the process of standardization, by American National Standards Institute (ANSI) and the Asymmetric Digital Subscriber Line (ADSL) Forum. As Figure 5 shows, the higher rates are for customers that are a short distance away from the network provider's xDSL modem. This modem may be located either in a central office (CO) or at a remote terminal site closer to many end users.

Figure 5. xDSL Downstream Rates

ADSL
ADSL is one of several types of xDSL technologies. ADSL has two main standards: ADSL–1 specifies a downstream rate of 1.5 or 2 Mbps and an upstream rate of 16 to 64 kbps; ADSL–3 specifies a downstream rate of up to 6.144 Mbps and a bidirectional channel of up to 640 kbps.
Good twisted-pair lines with no bridged taps can support ADSL–1 rates up to 18,000 feet (24-gauge wire), and ADSL–3 up to 12,000 feet.
ANSI and the ADSL Forum have endorsed discrete multitone (DMT) technology. However, carrierless amplitude and phase (CAP) technology has the most market-share thus far, with 30 times as many ADSL lines using CAP. DMT and CAP modems are incompatible, but the issue is not nearly as great as with VBD modems. VBD modems must be compatible end-to-end, from end user to end user. But ADSL modems only operate over the end user's twisted pair, from end user to network provider.

VDSL
Very-high-speed DSL (VDSL) promises even higher speeds than ADSL, although over much shorter distances. Standardization is underway in four different standards bodies: ANSI, the ADSL Forum, the ATM Forum, and the Digital Audio-Visual Council (DAVIC). There are four different technologies proposed (CAP, DMT, DWMT, and subscriber line charge [SLC]), aiming at a goal of lower power and less cost than ADSL.

RADSL
As the name implies, rate-adaptive DSL (RADSL) modems adjust the data rate to match the quality of the twisted-pair connection. Emerging software should make this an automated process with little human intervention.

HDSL and SDSL
High-data-rate DSL (HDSL) modems transmit 1.5 Mbps in each direction. Two twisted pairs of wires are used, with half of the traffic on each pair. A 2.0–Mbps transmission rate is also available, using three pairs of wires (one-third of the traffic on each pair). The wire limit is 12,000 feet (24 ga.) or 9000 feet (26 ga.)
Symmetrical digital subscriber line (SDSL) is similar to HDSL but requires only one pair of wires. Transmission speed ranges from n x 64 kbps to 2.0 Mbps in both directions.
HDSL and SDSL are intended as lower-cost replacements for dedicated T1 and fractional–T1 lines, rather than for residential access.

Twisted-Pair Access—Remote

The three major twisted-pair categories discussed under "twisted-pair access" can all be remoted, as is shown in Figure 6.

Figure 6. Twisted-Pair Access—Remote

Remoting mechanisms, such as digital loop–carrier systems, enable fiber migration into loop-access plant. They are a cost-effective way of bringing service to end users who are not located near access nodes. As shown in Figure 6, services are ultimately provided to end users over twisted pairs from remote terminals that connect via fiber facilities to the serving node.
As Figure 6 illustrates, remote systems can be terminated in two ways. One is a termination directly into a circuit switch; this is called the integrated access approach. The second approach has a host digital-terminal termination in the service node; this called the universal access approach. Both integrated and universal remote-access arrangements are used to provide Internet access. The choice of approach in any specific case depends on the embedded network and on the capabilities that must be provided to end users in addition to Internet access.

Fiber and Coax

There are three significant categories of combined cable and fiber systems used for Internet access. According to Figure 7, they are as follows:

Figure 7. Fiber and Coax

Cable TV Hybrid Fiber/Coax (HFC) System (Top)
Traditional systems have only downstream broadcast capability. These traditional cable–TV systems broadcast downstream in the 50- to 550/750-MHz band with 6-MHz channels.
Cable modems are used to allow Internet and data transmission in the downstream direction of the HFC system. Internet data speeds up to the 30–Mbps range can be realized in a nominal 6-MHz video channel. The upstream signal is provided by an existing telephone channel using VBD or ISDN.

Bidirectional HFC system (Middle)
These newer systems have transmission capability in both directions. Such bidirectional cable–TV systems typically broadcast downstream in the 50- to 750-MHz bandwidth of the coax within the 6-MHz nominal video channels. The upstream bandwidth is shared among all the homes passed by the coax cable and is nominally limited to the 5- to 40-MHz frequency band.
Downstream Internet data speeds up to the 30–Mbps range in 6-MHz channels can be realized. Upstream data is contention based and operates at claimed speeds of up to 10 Mbps. In practical multiuser environments, however, actual throughput speeds will be significantly less.
Cable modems can either be overlaid onto the HFC system or be an integrated part of the HFC system.

Switched Digital Broadband (SDB) Systems (Bottom)
SDB is classified as a baseband digital system with nominal 50–Mbps point-to-point downstream rates that can be apportioned as desired between digital video and data. For data, a 1.5–Mbps nominal, contention-based, upstream data bandwidth is available. Though the system is contention based, there is always a minimum guaranteed upstream data rate available—typically in the order of 16 kbps.
The three architectures described all have provisions for both analog and digital video broadcast capability.
Both the bidirectional HFC and SDB systems are broadband systems that are applicable to telephony, video, Internet/data, and PCS wireline access. Note that the architectures have a number of similar characteristics and components. The bidirectional HFC system provides fiber distribution to the fiber node. At the fiber node, signals are collected and distributed to multiple-coax feeds that cover a given residential area. Fiber nodes are designed to serve from 500 to 2000 homes.
SDB systems push fiber closer to the end-user. In typical systems, feeder fiber can be optically split. Optical network units (ONUs) terminate the fiber and provide individual coax (and twisted-pair) drops to subscribers. A typical ONU can serve from 4 to 60 homes. Thus, SDB provides fiber closer to the customer.
In many ways, HFC, SDB, and PON (discussed shortly) can be viewed as a continuum of technology where fiber moves ever closer to the customer premises.

Wireless

As Figure 8 illustrates, three means are used to provide Internet access using wireless technology: satellite broadcast, terrestrial broadcast, and cellular/PCS.

Figure 8. Wireless Access

Cellular
Internet access can be provided via existing cellular systems using voiceband modems. Because cellular channels are narrowband, access rates are limited to 9.6 kbps for advanced mobile phone service (AMPS) and time division multiple access (TDMA) systems and to 14.4 kbps for code division multiple access (CDMA) systems. Cellular digital packet data (CDPD) is a technique that enables the data rate of AMPS to be extended to 19.2 kbps. CDPD achieves the higher rate by inserting Internet protocol (IP) packets directly into cellular channels that do not contain voice traffic (i.e., channels that are temporarily idle).
Techniques are being investigated to provide Internet access and other data services using personal communications services (PCS). PCS data standards are being investigated by a joint technical committee of ANSI T1 and the Telecommunications Industry Association (TIA), the International Telecommmunication Union–Telecommunications Standardization Sector (ITU–T), and others.

Terrestrial Broadcast
The multichannel multipoint distribution service (MMDS), sometimes called "wireless cable," can provide Internet-access downlinks over a distance of about 50 km from a central-transmitter site. MMDS downlinks combined with telephony uplinks provide a complete Internet-access arrangement. MMDS operates in the 2-GHz frequency band with 33 channels, each capable of supporting downlink data rates that are currently about 10 Mbps. Technology improvements are expected to increase data rates to 27 Mbps in the future.
Local multipoint distribution service (LMDS) is similar to microwave multipoint distribution service (MMDS) in that it will use microwave transmission to provide Internet-access downlinks and wireline telephony to provide uplink access. LMDS will use transmitters operating in the 28-GHz frequency band with each transmitter covering a distance of about 5 km. The relatively close transmitter spacing, coupled with the fact that LMDS will have about four times the bandwidth of MMDS, should enable LMDS to serve a much higher density of Internet users than MMDS.

Satellite Broadcast
Several approaches have been proposed for using satellites to provide Internet-access downlinks. Some proposals are based on using a single fixed-position satellite, whereas others would use clusters of satellites. Proposed data rates vary from low-speed, single-user channels to shared channels with rates greater than one Mbps.
The first widely available system operates in the 12-GHz band and uses a data rate of 400 kbps. Equipment at the end-user location consists of a dish antenna, approximately 52 cm in diameter, a microwave receiver, and a digital decoder card that plugs directly into a PC computer bus. Satellite systems also use telephony circuits for uplink access.

All Fiber—PON

This all-fiber access system called a PON is intended for residential applications for Internet and other services access. The architecture shown in the top of Figure 9 has fiber from the service node to the optical splitter. At the splitter, multiple fibers fan out to terminate on a single-home ONU. The ONU then splits out to provide individual service to the home. There are many schemes for technical realization of PONs, the more interesting one consists of wave division multiplexing (WDM) for up to 16 ONU drops from the optical splitter. WDM techniques would again be used in the upstream direction to realize a highly secure point-to-point PON architecture.

Figure 9. Pure Fiber Access—PON

As it is all fiber, PON has many advantages. All fiber yields a robust outside plant that has low maintenance costs associated with it. All fiber point-to-point architecture allows for secure transmissions and broadband service applications.
The PON architecture represents the target wireline architecture because of its versatility and evolution-proof capabilities. However, initial costs of PON systems are still higher than most all of the other alternatives discussed within this tutorial.

All Fiber—SONET

All-fiber access systems consisting of SONET or SDH fiber rings are commonly used to provide high-capacity, multiservices (including Internet) access to and from campus and business locations. SONET is a North American–based standard for such an architecture with interface rates from 1.544 Mbps (DS–1) to 10 Gbps (OC–192). Similarly, SDH is the European-based standard for equipment with similar capabilities.
The bottom portion of Figure 10 shows a SONET/SDH connection from a service node to a business. The SONET/SDH ring provides service assurance via path-diversity ring architecture. In a campus environment, the ring could be extended through the various buildings that make up the campus.

Figure 10. Pure Fiber Access—SONET

On the customer premises, the customer's intranet, depicted by the local-area network (LAN), is connected to the public network via a firewall. The firewall provides data and security protection for the business. Firewalls provide security by isolating undesired Internet traffic from the traffic that is carried on intranet LANs. Multiplexers (Mux) provide transport efficiency by combining separate data streams onto a single fiber-optic facility. Synchronous transfer mode (STM) multiplexers widely deployed in telecommunications networks carry data streams within discrete tributaries. Asynchronous transfer mode (ATM) multiplexers can provide more interface-rate granularity because individual user data streams are concatenated into a single high-speed cell stream for transport within the network. In addition, ATM multiplexers can provide further efficiency by combining variable-rate data streams using statistical multiplexing.

Conclusion

All Internet end users want access systems to provide increasingly higher speeds at a reasonable cost. Many users also want their Internet access to be closely coupled with the means they use to access other services. What are the challenges to measure against in meeting these needs of Internet users?
As described in this paper, the first challenge—the technology challenge—has been met vigorously by ingenious network providers and equipment vendors who have created a wide variety of high-speed access systems.
The second challenge is cost. New technology is usually costly, and the difficult challenge of meeting cost targets can take longer than access providers and end users wish. Today, the lag from technology creation to economic prove-in is the throttle regulating the pace at which emerging high-speed technologies gain widespread acceptance.
As access providers conquer the first two challenges and become successful in providing low-cost, high-speed access systems, it is already clear that new challenges will arise. For example, some access systems achieve high peak burst rates by sharing broadband-access media among many users. Eventually, all systems may find it beneficial to use shared links in portions of the access network. Shared systems have different network-engineering considerations from individual circuit-based systems, so we can expect shared systems to spawn new network engineering challenges for dealing with congestion, quality of service (QoS), and other performance criteria.
Finally, there are challenges in meeting the needs of users who see benefits in having Internet access combined with access to other services such as entertainment video and work-at-home intranets. Solutions such as virtual networks are being considered to address these

Home Networking- An Overview

Definition and Overview

Definition

Home networking is the collection of elements that process, manage, transport, and store information, enabling the connection and integration of multiple computing, control, monitoring, and communication devices in the home.

Overview

Until recently, the home network has been largely ignored. However, the rapid proliferation of personal computers (PCs) and the Internet in U.S. homes, advancements in telecommunications technology, and progress in the development of smart devices have increasingly emphasized the last 100 feet of any consumer-related network (i.e., the American home).
Furthermore, as these growth and advancement trends continue, the need for simple, flexible, and reliable home networks will greatly increase. This tutorial addresses the market drivers, the current and future technologies, and the standards (or lack thereof) relative to home networking and the home-networking environment.

Market Drivers

According to Yankee Group estimates, over 30 percent of PC–owning U.S. households are interested in the concept of home networking. Several trends, however, contribute to the growing need and the potential success or failure of home-networking solutions.

The Changing Face of the Workplace
The Internet elicits many changes in the workplace. These changes, in turn, create a growing need for home networks. Driven by a changing corporate culture, cost-cutting measures, and clean-air acts that demand less travel to and from work, many employers have implemented telecommuting practices. To implement these practices, information technology (IT) managers must not only connect telecommuters to the corporate local-area network (LAN) and intranet but provide voice solutions as well. To conduct business properly, telecommuters must access files and stored network information and therefore require a high-quality, secure voice network able to sustain multiple lines. According to Telecommuting America, between 1995 and 1997 the number of home-based telecommuters grew more than 30 percent to 11.1 million. That number increased another 40 percent to 15.7 million in 1998. If such trends continue, the need for reliable home-network solutions will increase even further.
Also experiencing growth are small businesses, many of which begin in the home. According to Forrester Research, more than 13 million households—12.6 percent of all U.S. residences—contain a business. Projections indicate that 14 percent of U.S. homes will include some type of home business by the year 2003. These start-ups need small-business solutions that work well in a home environment.

PC–Based Households
Yankee Group research indicates that 43.1 million or 44 percent of U.S. households now have a PC. Of these, 9.4 million have two PCs, and 3 million have three or more. The percent of households with PCs is projected to grow to 54 percent in 2001, with the portion of multi–PC households growing to 24.5 percent.
Multi–PC penetration is driven by a number of factors. The widespread availability of PCs for less than $1,000 and the increasing number of home offices and individuals who bring work home contribute to the trend. Many analysts believe that these factors will drive the number of homes with PCs even higher than current forecasts. Such analysts also believe that multi–PC penetration rates will grow more rapidly than overall PC adoption.
In addition, demand for Internet access in the home continues to climb. According to the Yankee Group, 22 percent of U.S. households subscribe to an on-line service or an Internet service provider (ISP). Many of these households also purchase additional PCs and telephone lines dedicated to Internet access.

Managing Smart Devices
The American home is also changing. Now in the process of development is an increasing number of smart devices that allow users to control and monitor events in consumer-based appliances, home electronics, and home-security systems. Indeed, 1999 will be the first year that non–PC central processing unit (CPU)–powered devices such as computer games, phones, personal digital assistants, set top boxes, and other consumer goods will surpass PCs in number of units shipped (see Figure 1).

Figure 1. Post–PC Devices

As these devices become more common, the need will increase for a home-networking strategy that will allow all data, voice, and smart devices to be accessed at any time from anywhere.

Simplicity and Reliability Are Essential
Whatever the trends, the key market drivers for home networking are simplicity and reliability. If the process is not maintenance-free, easy to use, and quick to install, it will not likely be embraced. While consumers desire the sophisticated functionality of an LAN—voice networking, shared Internet access, and smart device control—they do not wish to engineer or administer a complex system. They want plug-and-play functionality, believing that only experts require technological know-how and that—much like telephones—PCs should just work.

Wired Home-Networking Technologies

These early networks are bulky, largely point-to-point loop- or star-based systems. For the most part, those with any robust capacity are tethered systems limiting the mobility and flexibility of their users.

Twisted Copper-Pair or Coaxial-Based Transport Systems (Ethernet)
The typical topology of these systems is demonstrated in Figure 2.

Figure 2. Typical Ethernet System

This technology is based on the Institute of Electrical and Electronic Engineers (IEEE) 802.3 standard, which has undergone many revisions since its conception to enable interoperability between many manufacturers. Copper-pair or coaxial-based transport systems are bidirectional, typically have a high degree of reliability, and are thus widespread among businesses as the standard choice for networking office PCs and printers. They require the use of bulky Category 5 (CAT5) cabling, and are typically expensive to install. Some home networks have Ethernet, but because of its expense and difficulty to install, few have chosen to use it.

Twisted Copper-Pair-Based Systems (Phone Line)
The typical topology of these systems is demonstrated in Figure 3.

Figure 3. Typical Phone Line System

This technology uses the existing phone wiring found in most homes today. In some cases, CAT3 wire elements transport at a date rate of 1 Mbps, and many speculate that it will support up to 10 Mbps in the near future. This technology claims to work simultaneously with regular phone service, without attracting the user's notice. The Home Phone Network Alliance (HomePNA) is one organization dedicated to the development of standards and specifications for interoperable, home-networked devices that use existing twisted-pair phone wiring. Although solid progress has been made toward enhancing the usefulness of this embedded asset, inflexibility and capacity limitations will limit its success. A typical home does not contain many RJ–11 jacks; they are rarely in every room or in the location where access by additional phones, computers, and other devices is required.
In addition, selection of signal characteristics for data transport over this medium is critical to resist interference from other shared devices. These devices include answering machines, fax machines, modems, telephone sets, and other data-transport devices such as the integrated services digital network (ISDN) and digital subscriber line (xDSL) equipment that use the twisted pair simultaneously.
Two-Way Coaxial Cable–Based Transport Systems (Broadband)
The typical topology of these systems is demonstrated in Figure 4.

Figure 4. Typical Coaxial System

This technology uses the same type of coaxial cable that is used by cable TV. It provides a reliable medium for data transport and has long-distance capability. Typically used by cable operators to send data into the home, it terminates near the television and is thus an uncommon means of distributing data through the home.
Selected suppliers of bidirectional coaxial cable–based systems do, however, use coaxial cable to distribute data through the home. One such supplier is Canada Ltd., which offers IBM Info-Structure Wiring™ components. IBM Info-Structure Wiring components consist of three CAT5 and two RG–6 coaxial cables. These start at the basement of a home at a distribution panel similar to the electrical box, connecting the services into a home and routing or directing them to several locations throughout the home. Each location in the home that connects to these services has an info-port. The info-port allows four telephone connections: one connection for a data network within the home and an extra outlet for future fiber-optic cable, distributed cable TV, and distributed satellite services.
In order for the IBM system to allow PC–to–PC networking, a combination of coaxial cable and twisted pair are used. There are no systems that allow for PC–to–PC communications using only coaxial cable.
These home-network transport systems require preplanning with homeowners, builders, or developers, because the systems are limited to network access by well-placed jack locations. Specific applications are best accommodated with a room-use plan before installation. Postinstallation upgrades for new access locations have limited success or flexibility without surface wiring and jack installation and add substantial additional expense.
Alternating Current Powerline-Based Transport Element
The typical topology of these elements is demonstrated in Figure 5.

Figure 5. AC Powerline-Based Transport Element

Alternating current (AC) powerlines are readily available as network transport elements throughout a home. They are used as transport facilities to send and receive discrete frequency-based control, monitoring, and communications messages to smart devices that manage lighting and environmental systems ("turn off," "turn on," and "dim"). They also are used as voice-communication elements for telephone extensions, computer-modem access, and intercom devices through standard electrical outlets. Throughput for any application requiring higher data rates can be a challenge. In addition, no standards exist to ensure interoperability between manufacturers.

Wireless Home-Networking Technologies

Wireless-Based Transport Element (Irda, Analog Cordless Phone)
The typical topology of these elements is demonstrated in Figure 6.

Figure 6. Worldwide Local-Loop Demand

Traditional wireless home-networking technology is used for line-of-sight, infrared, unidirectional, hand-held controller applications. Typical uses today are for VCRs, TVs, and some security and alarm applications. The other obvious wireless technology is the cordless phone. However, neither can be definitively classified as a robust home-network element. The cordless phone still requires the twisted copper pair and a jack as an access point, and today's infrared applications rarely leave the confines of the home.

Wireless-Based Transport Element (Radio Frequency)
Currently, there are several standards and working groups focused on wireless networking technology (radio frequency [RF]). These include the IEEE 802.11, HomeRF, Bluetooth, and standard wireless access protocol (SWAP). Wireless-based transport element technology can be used to distribute multiple types of information within the home. Some examples use a discrete controller device, some a PC as a controller device, and others no controller device at all (i.e., peer to peer). Wireless RF transmission is the recognized home-networking topology of choice for the emerging network-centric home as a result of its flexibility, mobility, and ability to network without wired connections.

The RF Transport Network Element
Most emerging home-networking wireless systems utilize spread-spectrum technology. This technology offers high bandwidth capacity and is used widely in the military, as it is secure and reliable. Two types of spread-spectrum radios are in common use today: frequency-hopping spread-spectrum (FHSS) and direct-sequence spread-spectrum (DSSS) radios. These radios will not interoperate, as a result of different frequency bands and vendor systems. System selection is critical, and once the user engages a supplier, it is difficult to transfer to another—even in those cases where industry standards are in effect. De facto or proprietary standards reign.
FHSS is a narrowband carrier with changing patterns of transmission that are recognized by both receivers and transmitters. When the two devices are in synch, they produce one logical communications channel.
DSSS produces bit patterns called chips or chipping codes. Reliability is based on the length of the chipping code or on how many bits of data it carries. Because an error-correcting function is built into radios, it is often not necessary to retransmit data, thus improving performance.

PC or Non–PC–Based Wireless Systems
System suppliers use several approaches, two of which are detailed in this tutorial: a PC–centric, data-only application and a data and voice home-networking application.

The PC–Centric, Data-Only Network
Some software and hardware suppliers provide home-networking solutions via a wireless LAN, using the home's PC as the central control element. Figure 7 reflects a wireless home LAN configuration in which one PC acts as a master to the network. It provides network addressing and routing between the home and the Internet.

Figure 7. PC–Based Wireless Home Networking System

This straightforward approach simply marries familiar PC technology to new home-networking technology. It also represents some consumer-marketplace challenges to ultimate mass-market success.
First, a home network built around a master PC implies that the PC will always be on and available for communications. It also implies that no other software or hardware application running on the PC can interfere with its ability to perform its communications tasks. Consumers are somewhat forgiving of PCs that have fatal errors and must be rebooted. They generally do not forgive their communications-network failures, because they expect the network to function smoothly at all times—as it historically has.
Second, a home network built around a master PC only addresses the PC–related network elements in the home such as file and printer sharing, multiuser game playing, and a single shared ISP account. It leaves the other elements such as voice communications and control and monitoring applications without a solution.

The Controller-Based Data and Voice Home Network
Figure 8 demonstrates the use of one integrated home-network system available on the market today.

Figure 8. Voice and Data Wireless Home Networking System

In this scenario, the microprocessor-based digital switch acts as the communications server, addressing and routing voice data traffic throughout the home. It also sends the home network–transport element through a powerful on-board RF transceiver. The transceiver is based on patented digital spread-spectrum technology and has an effective reach of several hundred feet from the home.
The controller shown in Figure 8 supplies a robust home network for voice and data with high bandwidth capacity. It is the bridge between the transport network element serving the home from the customer-selected service provider and the wireless home network. Networked devices require no wires or fixed wired jacks. This system also offers several hundred feet of accessibility within and outside the home. There are no relocation restrictions. Data and voice services, including internal device-to-device communications, are commonplace.
There are four distinct functional areas served by a controller-based, data and voice home-network system:

• home local-area network—Networking capabilities provide the home-network user an easy-to-install LAN between all PCs within the home. This allows sharing of computer files, printers, and disk drives and supports multiplayer PC games via a wireless Ethernet and a transmission control protocol (TCP)/Internet protocol (IP) LAN.
• Internet gateway—The controller provides an Internet gateway addressing and routing function for sharing a single ISP account and connection with all PCs. All surf the Internet at the same time on only one 56-kbps, 128-kbps, or faster account, with only one monthly charge.
• Wireless voice networking—Each wireless handset can view and manage up to four plain old telephone service (POTS) lines while the PCs are simultaneously being used on the LAN. The handset displays allow users to access caller ID and voice-messaging status information and make decisions about call management in real time.
• Traditional wireline POTS networking—All telephone lines serving a home terminate on the controller. They are then distributed to wireless handsets or to wireless RJ–11 phone jacks with built-in transceivers to which standard telephones, fax machines, or modem-equipped PCs can be connected.

The non–PC–based switching center (the controller in Figure 8) is software derived so that new networking requirements in the home can be met without wholesale changes. Future developments for home networking are outlined in the next module.

The Future

The American home is the center of a convergence of competing technologies, architectures, and suppliers, each with a unique set of advantages and solutions. Systems are being researched, developed, and deployed to manage, monitor, and control the following list of functions:

• Data and voice communication needs internal and external to the home
• Electronic entertainment devices
• Service appliances that prepare food
• Service appliances that maintain the home appearance
• Systems and devices that maintain the in-home environment
• Devices that keep the home secure from intrusion or damage from internal and external man-made or natural events

Successful home-network system providers must develop capabilities that are upward compatible. A central controller (the brain, microprocessor, switcher, or data storage device) to capture home-network events and react in conditioned or learned responses is essential to future product innovation.
The home-network transport medium of the future will be wireless, as is dictated by the homeowner's need for flexibility, the moving continuum of product development, and the high cost and sheer inconvenience of wire-based installations.
In addition, consumers will require a system that manages everything within the home, including voice, data, and appliances. Wireless technology will provide necessary convenience, simplicity, and long-term cost savings.

Home-Networking Standards and Specifications

Standards, whether established by standards bodies or leading system suppliers as de facto standards, will play an increasing role in system development.

Many different formats for standards and specifications are emerging in home networking, including the following:

• IEEE 802.11 wireless LAN—The IEEE 802.11 standard defines the protocol for two types of networks: ad hoc and client/server networks. An ad hoc network is a simple network in which communications are established between multiple stations in a given coverage area without the use of an access point or server. The standard specifies the etiquette that each station must observe so that all stations have fair access to the wireless media. It provides methods for arbitrating requests to use the media to ensure that throughput is maximized for all users in the base service set. The client/server network uses an access point that controls the allocation of transmit time for all stations and allows mobile stations to roam from cell to cell. The access point is used to handle traffic from the mobile radio to the wired or wireless backbone of the client/server network. This arrangement allows for point coordination of all of the stations in the basic service area and ensures proper handling of the data traffic. The access point routes data between wireless stations or to and from the network server (http://www.wlana.com).
• a 2.4 GHz band using a relaxed IEEE 802.11 standard and digital European cordless telephone standard
• Bluetooth—Bluetooth radio technology provides a universal bridge to existing data networks, a peripheral interface, and a mechanism to form small private ad hoc groupings of connected devices away from fixed network infrastructures. Designed to operate in a noisy RF environment, the Bluetooth radio uses a fast-acknowledgment and frequency-hopping scheme to make the link robust. Bluetooth radio modules avoid interference from other signals by hopping to a new frequency after transmitting or receiving a packet (http://www.bluetooth.com).
• SWAP 1.0—The SWAP system can operate either as an ad hoc network or as a managed network under the control of a connection point. In an ad hoc network, where only data communication is supported, all stations are equal, and control of the network is distributed between the stations. For time-critical communications such as interactive voice, a connection point is required to coordinate the system. The connection point, which provides the gateway to the PSTN, can be connected to a PC via a standard interface such as universal serial bus (USB) that will enable enhanced voice and data services. The SWAP also can use the connection point to support power management for prolonged battery life by scheduling device wakeup and polling (http://www.homerf.com).
• X10—This is a communications protocol for remote control of electrical devices and communications over standard household AC powerline wiring (off, on, and dim functions).
• IEEE 1394—This is a serial interface for short-range, low-data-rate, infrared communications between entertainment and computer devices.
• Home Phoneline Networking Association (HomePNA)—Home phoneline–networking technologies must tolerate completely random and unspecified wiring topologies. They must also be designed to take into consideration the unknown but typically large degree of signal attenuation that occurs within the random tree network topology. A transmitted pulse is attenuated and scattered on the wires as it bounces around inside the wiring. The longer the pulse travels through the wire mesh inside the house, the more it attenuates and dissipates. Home phoneline–networking technologies require high and varying levels of signal noise and must tolerate dynamically changing transmission line characteristics, while coexisting with telephone service and complying with Federal Communications Commission (FCC) Part 68. Lastly, they must maximize data throughput given the above constraints and limitations (http://www.homepna.org).
• HWN SSERQ/AAWG—Superspread equilateral reservation queueing (SSERQ) protocol is optimized for wireless transport of voice, data, and multimedia services. Its packet-reservation scheme provides the high QoS and access priority required for voice and multimedia services. Wideband, common-channel signaling permits rapid setup and takedown of virtual private circuits for high-speed intranet traffic and Internet access. SSERQ supports IEEE–802.11 infrastructure-mode (client/server) networking via the air-to-air (air-squared) wireless gateway, which provides translation, supervision, and transport between 802.11 and SSERQ networks (http://www.homewireless.com).
  

Broadband Media Services- A Brief Introduction

Definition and Overview

This tutorial describes the evolution and technologies involved in broadband media services delivery. A brief history tracing the evolution of broadband media services will be presented, along with descriptions of multimedia standards, potential services, and the roles of the various entities involved in creating broadband media services–network providers, content providers, services providers, and businesses and consumers. After working through the tutorial, participants will have a general understanding of the scope, technology, and benefits of broadband media services.
Broadband and bandwidth"Broadband" refers to a type of network connection that supports a very high bit rate, as opposed to "narrowband," which supports a lower bit rate. The higher the bit rate, which is a measure of speed of transmission of bits per second (bps), the faster the transmission will occur in a given period of time. "Bandwidth" is a measure of capacity. Greater bandwidth allows more information to be communicated in a given period of time. Broadband media services delivery requires transmitting large amounts of information quickly, so the combination of fast broadband transmissions and large amounts of bandwidth required to deliver information are the foundation of broadband media services delivery. But this is just the beginning of the broadband media services story, because the true value of broadband media services lies in the actual services that can be delivered across these high-speed, high-bandwidth networks, the entirely new "on demand" way customers will access them and the customized and personalized ways that individuals will interact with these services. With that in mind, we can formulate a definition of broadband media services:
Broadband media services is the seamless, customized, "on demand" creation and delivery of multimedia services to homes, businesses, and mobile users, including entertainment services (movies, interactive games, broadcast TV), infotainment (e-learning, online training) through high-speed Internet protocol (IP) networks.
Beyond fast Internet access"Broadband media" is sometimes called "streaming media" because the services, or "content," that is delivered via broadband networks is digitized, and received by users of the content in continuous real-time "streams." Broadband content is digitized and accessed utilizing IP, the standard protocol used for Internet access today. In fact, high-speed IP access through digital subscriber lines (DSL) that utilize existing voice lines for high-speed transmissions, is the foundation of the broadband media services network, and DSL is available in many parts of the world today. DSL is a group of increasingly high-speed technologies that enables fast Internet access in homes and businesses. DSL "always on" connections will also form the basis of the sophisticated broadband media services networks of tomorrow.
Fast Internet access barely scratches the surface of the powers of broadband, DSL, and IP technology, which, combined in broadband media services, will connect people and businesses around the world like never before. Broadband media services will put the consumer in total control by enabling personal, custom, on-demand viewing of entertainment, e-learning, video games, and other types of content. Individuals will choose what they want to hear, see, or be entertained by on their own, and people will no longer have to plan around preconceived broadcast schedules for home entertainment. Eventually, we will decide our own schedules for much of our entertainment. Furthermore, broadband media services will allow individuals to easily create their own content, personalize it, and distribute it for viewing on TVs, PCs, remote laptops, and mobile phones and other wireless devices around the world, instantly.
Broadband media services provides endless possibilities for consumers to choose and personalize their entertainment and infotainment. Broadband media services will also create new revenue streams for operators, media companies, and service providers through enhanced usage of existing networks, branded media portals, interactive "one-to-one" advertising and endless e-commerce possibilities. The proliferation of high-speed broadband IP access and broadband media services will require content creators to distribute large amounts of rich media to a global audience of high-speed users with increasingly greater demand for access to specific services. The challenges for broadband media development include understanding true consumer wants and needs for services and perfecting the technology standards behind the high data rates and significant bandwidth required for seamless delivery of high-quality multimedia services.

Broadband Media Services Evolution and Market Potential

It is estimated that by 2004 there will be more than 65 million DSL subscribers, and 16 million of those will subscribe to broadband media services. The market for broadband media services is driven by:

• Content providers pushing new types of content to the Internet
• New broadband access technologies enabling cost-efficient media services
• Broadband DSL services which will enable fixed operators to capture part of consumer's new TV and video services and bundle them with traditional voice services, helping to reduce customer churn and margin pressure
• Increasing demand followed by growing market awareness

In addition to media revenues, broadband media services can provide new revenue sources such as advertising, interactive services, and e-commerce revenue sharing. How did the demand for next-generation IP services evolve? Why do telecom operators find broadband media services so compelling? To answer these questions, let's first take a brief look back at the evolution of broadband media services, and how broadband media services can create new opportunities for telecom operators.

Figure 1. Expected Broadband Media Services Subscriptions (in millions)

A little over 25 years ago, operators had no concept of using telephone lines as anything other than carriers of voice traffic to consumers. Before divestiture in the telecom world, and for many years after, the only service operators offered to consumers was basic voice service. The cable and home-video industries were also in their infancy. Other than network television and radio, entertainment meant that consumers went outside the home, to movie theatres, shows, or concerts. The cable industry consisted of a few small start-up companies, basically small groups of people positioning a large antenna, hooking up analogue line amplifiers to feed the signal, and routing the signal to multiple homes. The few cable operators that existed at the time were small and mainly focused on their growing cable-programming customer base. At the same time, telecom operators had a firm hold on voice service. While telcos and cable companies serviced many of the same customers with their respective services, there was otherwise little convergence in the entertainment and telecommunications industries.
Then, beginning in the early 1980's, and especially in the last 10 years, the telecommunications industry was forever changed. The proliferation of the wireless and home-entertainment industries, including cable, home computing, and widespread use of the Internet, has created both opportunities and challenges for traditional operators. Some have experienced bankruptcy or were merged with other companies. The few that remained were faced with new competition from start-up telecom companies, Internet service providers (ISP) and content providers for a share of the growing consumer telecommunications dollar. As many of these start-ups were forced out or merged, the dominant companies that remained had tremendous opportunities to bring more value to the consumer than ever before by providing first dial-up, then high-speed, or broadband, Internet access. Today, substantial revenue increases for telcos derived solely from voice services are limited, because of market saturation. New revenue sources must be integrated into their existing product lines. Enter broadband media services.

Broadband Media Services Market Potential for Operators
The role and scope of the telecom, Internet, and entertainment industries as global powerhouses have played an important role in the emergence of broadband media services. While cable and satellite remain viable markets for home entertainment, broadband media services delivered via IP have applications above and beyond movies and music, for both homes and businesses, and offers several advantages. As Internet content becomes more sophisticated and media companies expand development of digital content in Internet-compatible protocols, the demand for broadband media services will grow exponentially. As a result of this growth, operators will have significant opportunities for generating additional revenue. The telcos' huge base of residential voice customers is a ready market for next-generation media services.

Some of the major benefits of broadband media services include the following:

• The infrastructure upgrades that are required for broadband media services do not involve significant civil and building-code regulation. In other words, to deploy broadband media services in an urban area, operators utilize their existing network infrastructure, so less land will need to be dug up to reinstall new infrastructure.
• Broadband media services revitalizes the revenue potential of the telcos' existing infrastructure by providing new opportunities to service existing customers.
  Broadband media services offers telcos a way to compete with cable (CATV) operators' packaged "voice + CATV services."
• A higher level of security is possible with IP networks. Since users are authenticated, or recognized, truly customized services and marketing opportunities based on specific user interests can be created. This is not possible with current broadcast networks.
• New levels of customization and interactivity are possible, combining Internet with broadcast television or DVD, for example. Bundles of services are no longer pre-defined and schedules become obsolete—users decide on the media they want, and determine on their own when they want to experience it.
• The power of the Internet is taken to a new level with broadband media services, in that individuals can create their own content and distribute it to electronic devices around the world (televisions, wireless phones, laptop computers, etc.) at the click of a button.
• Since services are individual and not bundled, upgrades are done on a per-customer basis, unlike CATV where fundamental changes require upgrades to all served on a common/shared infrastructure.
• Pay TV (CATV or satellite) is an established service in many countries, so there is reason to believe that telcos that offer broadband media services will find an eager customer base willing to pay, providing customers recognize the value of broadband media services over existing entertainment services.

Generating marketing messages that will convey the value of broadband media services to customers will be crucial to obtain new subscribers and for consumer word-of-mouth diffusion to kick in and grow the broadband media services market. In order for telcos to be ultimately successful in deploying broadband media services, they will need to work closely with network and content providers to ensure that services are deployed and marketed effectively to their customers.

Broadband Media Services Technology (Network, Components, Standards)

Just as the Internet will continue to bring people together and provide individualized services like never before, the IP network technology that enables broadband media services is rapidly improving and becoming more powerful. This section of the broadband media services tutorial will provide an overview of the network and component technology required for end-to-end broadband media services provision, as well as an overview of technology standards involved in digital multimedia content creation and transmission.

Next-Generation Networks

In a truly mobile information society, mobility, traditional fixed and mobile-network services, value-added services, and the Internet are all combined to offer seamless services for end-users. As uniform services will be available through different access points and optimized for each device (TV, PC, wireless device, etc.), seamless roaming among multiple access devices will be required. Users won't have to be concerned with the underlying technologies used, but they will be concerned with being able to access the same services wherever they are and whenever they choose.
The Next-generation network, the first truly data-oriented broadband network supporting broadband media services, will be all IP, meaning all access to the network will occur via IP standards. The evolution of the broadband media services network can be characterized by six different transitions:

• Transition from a dial-up-like circuit-switched network to a data-oriented network
• Transition from connectivity to service-creation platforms
• Transition from a copper-based network towards an all-optical network
• Convergence of fixed networks
• Convergence of mobile and fixed networks
• Transition to IP version 6 (Ipv6) networks

In short, next-generation networks will evolve to better reflect the requirements of broadband media services. In practice this means bringing IP and other associated network functionalities in the network closer to the customers. The DSL technology and network components that enable high-speed IP access and basic broadband media services exist today, and will remain the foundation of the next-generation broadband media services network:

The major components of a broadband IP access network and next generation broadband media services network are

• High-speed DSL access multiplexers (DSLAM) equipment, located in the operator central 0ffice (CO) and/or in remote locations close to end-users
• Broadband access servers
• DSL modems in the home and/or office providing fixed local-area networks (LAN) and wireless LAN (WLAN) network access
• Network- and service-management and provisioning products
• Loop management for managing DSL services in the local telecom loop
• IP network security and authentication products for network security and user identification

In addition to network infrastructure, network services will manage and enhance the physical network for broadband media services delivery. Broadband media services network integration services could include network capacity planning and business consulting for network optimization and interoperability, network installation setup and field-testing trials, customer-service support and training, and network validation and certification services.

Components

With the IP access network as a foundation, broadband media services–specific network enhancements are required. The broadband media services components can have varied functionality with just a minor change in the presentation of the feature, which is required for a modular and scalable solution as new services are created and consumer demand for additional services evolves. Essentially, broadband media services allows consumers to customize their viewing via network control devices. Each set of devices or "boxes" can support a unique content lineup map, which enables consumers to select and pay for only the media that interest them. Specific standards mentioned, such as moving pictures expert group (MPEG), are described in greater detail in the "Standards" section, and specific services, such as voice on demand (VOD), will be described in the "Services" section.

Figure 2. Broadband Media Services for the home

Video Encoders

Video encoders are devices that create digital video. Input to the encoders can be analogue video or a Digital Video Broadcasting Group (DVB) multiplex. Both are required because some video content will be statically loaded from video tapes and some content will be captured from a satellite (DVB) multiplex. Video encoders that are used to deliver broadband media services most often allow for the creation of MPEG content and have the ability to support IP multicast at varying bit rates, as well as the ability to decrypt video streams to remove conditional access.

Video Servers

Video servers perform two major functions. First, they act as content repositories for the material being streamed. Second, they are responsible for streaming out video and audio using the desired format and network protocol. Video servers can be scaled from streaming 20 to over 5,000 simultaneous video streams. Video servers generally support several different transport protocols for video delivery.

Interactive Television

ApplicationInteractive TV (ITV) applications consist of many different applications. The core of the system is the application framework and the data-handling capabilities of the back-end systems. Highly scalable for add-on features, the fundamental applications in an ITV system are customer relationship management (CRM) software modules that track customer usage, profiles, buying characteristics, and application subscription information and create billing events that-can be exported to various billing systems. Applications that typically run on the application framework are VOD, time-shifted TV, web access integrated with video applications, e-mail, personalized user interfaces, broadcast multichannel TV, and pay-per-view applications. Variants of these fundamental applications include channel blocking; parental controls; instant web access associated with viewing preferences for an enhanced, interactive viewing experience; video special offers; and targeted advertising.

Set Top Box and Customer Premises Equipment

The set top box and customer-premises equipment (CPE) are devices that are placed in consumer homes or offices, either as two separate devices or as one device combining the home or office gateway functionality required for broadband media services delivery to fixed and wireless devices. A set top box is an electronic device that serves as an interface between a television set and a broadband network, providing VOD and interactive multimedia services. CPE is any type of network device that sits in the home or office of the consumer, as opposed to the central network office or remote sites. User connections to broadband media services are made through modems and media terminals in the home and office, while the main infrastructure lies in the back-end networks, invisible to the end-user.

Standards

To help ensure the interoperability, modularity, and flexibility of services, network, content, and service providers are driving towards open standards for individual broadband media services. Standards forums meet regularly to enhance existing standards, incorporate new technological developments into current standards, agree on next steps for testing, and anticipate new developments that will affect standards. Some of the standards involved in broadband media services are

IP

This is a standard supported by major application providers, software companies, and computer manufacturers. Since the range and variety of broadband media applications are more important with respect to commercial revenue-bearing services than any one specific application, enabling the integration of a broad range of media services and applications, IP is crucial. Without IP as a unifying protocol, the set of applications could be limited. One of the features of broadband media services is that it takes full advantage of the guarantees provided by IP access products with respect to real-time IP data delivery. The network provides real-time guaranteed IP data delivery. This clearly removes the burden of bandwidth management off the consumer applications and enables the developers of consumer applications to focus on the usability issues as well as providing an enriched user experience. IP provides the path that allows applications to evolve, independent of the transport protocols selected for broadband delivery.

IPv6

This is the new IP to replace the current version, IP version 4 (IPv4). IPv6 has been designed to meet the challenges of the growing Internet and includes several improvements over IPv4. The main benefits of IPv6 include a larger address space, integrated security, support for auto-configuration of terminals, and support for mobility.

MPEG

This is a digital video and audio compression format that was defined as part of the International Standards Organization (ISO). MPEG is a compression method that uses interframe compression. Interframe compression assumes that although something is happening in the foreground, the background in most video frames remains the same. This means that it is not necessary to compress each entire frame, but only the differences between them.

MPEG–2

MPEG–2 is a widely used, standardized video coding and compression technology. MPEG–2 is used in DVD movies and digital satellite distribution. Non-compressed video stream is roughly 200 Mbps, but with MPEG–2 the video can be encoded at 1.5–18 Mbps. DVD quality can be reached between 5–9 Mbps, but 2–3 Mbps is enough to exceed VHS quality. MPEG–4 is also a video coding and compression technology.

MPEG–4

MPEG–4 is a compression/decompression technology that aims to achieve interactivity, efficiency, and stability in transmissions. The result of another international effort involving hundreds of researchers and engineers from all over the world, MPEG–4 offers higher video quality and resolution at a lower data rate than MPEG–2. Also, the MPEG–4 stream encoding rate range is wider (5 kbps–60 Mbps). MPEG–4 allows interactive objects in the stream, making it more multimedia ready. On a broader level, MPEG–4 aims to pave the way toward a uniform, high-quality encoding and decoding standard that would replace the many proprietary streaming technologies in use on the Internet today. MPEG–4 is also designed for low bit-rate communications devices, such as wireless mobile devices that can display video. MPEG–4 supports scalable content, which means content is encoded once and automatically played back and transmitted at different rates depending on the available network connection.

Real-Time Streaming Protocol (RTSP)

This defines the control interface between video server and video client. With RTSP, the end user can control the video server as he or she would control the home VCR (play, pause, fast forward, rewind, etc.) RTSP also initiates the video streams and identifies different streams in the network so that the information can be used in billing.

Internet Group Management Protocol (IGMP)

This is a protocol that supports IP multicasting, a method of broadcasting that authenticates end-users prior to receiving content.

Very High Bit Rate Digital Subscriber Line (VDSL)

This is an extremely high-speed DSL technology for transmitting digital information over short reaches of an existing phone line to homes and businesses. With VDSL, transmission rates are very dependent upon actual loop length. The maximum downstream rate is between 51 and 55 Mbps over lines up to 1000 ft (300 meters) in length. Initial upstream rate will be an asymmetric rate between 1.6 and 2.3 Mbps. The data channel will be a separate frequency than that of bands used for plain old telephone service (POTS) and integrated services digital network (ISDN), thus enabling service providers to overlay VDSL onto existing services. As needs arise for higher-speed upstream rates, VDSL may need echo cancellation.

Examples of Services

The variety of broadband media services that consumers will receive is only limited by the creativity of network, service, and content providers. While research is being conducted regularly to determine demand for specific services, one thing is clear—for broadband media services to have successful deployment, the services will have to add value to individual lives. User interface (UI) is an important component of this, and the interface and controls have to make sense for users. Ideally, users would control and access content with familiar remote-control devices and create and select content via customized on-screen menus according to their preferences. An example would be a single on-screen menu (viewable on the users TV, PC, etc) that provides access to the home DVD collection, music library, video game library, Internet and e-mail, e-greetings library, family photos, broadcast TV, pay-per-view options, and more. In the office, a single interface could provide access to employee-training videos, industry discussion forums, Internet and e-mail, and other company news and information. Since ease of use is a crucial part of the overall solution, companies are actively researching consumer preferences for integrated media interfaces to offer a variety of options that address individual tastes.

The three cornerstones of Broadband Media Services are

• truly customized "per customer," "per media type" access to multimedia content
• Content "on demand"—what you want, when you want it
• Advanced interactivity

With that in mind, broadband media services are probably best described as a mix of

• Internet applications (interactive surfing of the WWW)
• e-commerce
• pay-per-view
• interactive targeted marketing

To better understand the potential of broadband media services, here are a few real-world examples of services that are being intensively developed and tested.

Media on Demand
On-demand experiences are a cornerstone of broadband media services in that users can consume content when it is convenient for them, as opposed to planning viewing or listening times around a preconceived, generic broadcast schedule. Generally, a media on demand (MOD) system's primary goal is for a client to request video or music and have it play back without interruptions, with little or no delay. MOD means that the content starts playing back from the beginning or from some specified point as opposed to joining a transmission in progress. An MOD server operating on the Internet today uses IP protocols to deliver the data. These protocols define how the server encapsulates the media file into packets and how a client decodes the received data. In MOD, content is "streamed" to the viewer in real-time. The recipient may choose whether to view the content the same time it is streamed (which is possible) or save the content in the video server to view another time.
Much more than movies or VOD, MOD could be anything—music, interactive games, university courses, vacation videos, replays from last night's hockey game, a scene from your favorite music video, a video phone call with grandma and the kids, your real-time stock portfolio with different scenarios e-mailed from your broker, a live Webcast for work. You get the idea! The premise of broadband media services is the same in that all digital content transmitted through IP networks can be "streamed" to devices and/or saved in servers, merged with other content, and ultimately viewed and interacted with. And, you will have fast, seamless access to it via a customized on-screen menu, viewable from different devices such as TV sets in different rooms of the house or PCs at the home or office. Here are two examples:

• It's Saturday night and you feel like staying home and watching a movie. You heard about a great foreign movie but you haven't been able to find it near your home. You log on to your broadband media services because you know your personal video search engine will help you locate the movie online. Then you will buy it and have it "streamed" to you instantly, but only after you've seen a preview. After you watch the movie, you notice a personalized message from the provider indicating the release date of another movie by the same director, along with a preview of the movie and an offer for 20 percent off your next purchase. Since you enjoyed this movie so much, you go ahead and order it in advance and specify the date you'd like it to be sent to your home server. Then you click on your "late night music" selections on your entertainment menu and play a few tracks from your jazz music library before you finally doze off.
• Your daughter's friend from school just got a new interactive video game for her birthday and your daughter has been rightly chosen to be the first to play with her. The only problem is, your daughter is tired from a long day by the seaside and she doesn't want to get up from the sofa. So, you fire up the laptop and drop it in her lap while her friend streams the game from her home server to yours. As your daughter desperately tries to outwit her friend at the game with the help of your speedy WLAN laptop connection, her friend has unwittingly downloaded a few "hints" from a private Internet site only available to buyers of the game. Feeling guilty after beating your daughter five games in a row, her friend decides to send a quick video demonstrating the hints for a more even match tomorrow.

Live IP Broadcasting
Of course live broadcasts exist today, but broadcasting of live events in real-time over the Internet provides a completely new range of entertainment possibilities that can be offered to end-users. There are no channel limitations and the coverage is global. Live video feed can be captured using real-time video encoders and then streamed to video servers. Broadcasting of live streams could also mean receiving satellite, cable, or terrestrial TV channels and encoding them into the IP network. Here are some examples of what IP broadcasting will mean:

• You've recently moved out of the country. You like your new home and job but you miss the local news back in your hometown, and especially the extensive coverage of your old high school football team that recently made it to the playoffs. With IP broadcasting, you can watch your local news every night and you won't miss a thing. And, you can have the local broadcast of all the playoff games "streamed" to you via IP broadcasting.
• You have tickets to the symphony but your boss just handed you a last-minute business assignment so you won't be able to go. No problem. You can have the symphony "streamed" to you in real time and keep it on in the background, while you're working, hearing it just as if you were there live. Since you've saved it on your home server, you can replay it again and again for the full video experience later.

Regional production of global sports events, concerts, and local events in real-time will become a reality and will create new revenue streams for operators. For consumers, IP broadcasting will become as close to "being there" for the live event as one could possibly get and allow people to keep close ties with favorite local programming around the globe.
New revenue opportunities abound for service providers, as broadband media services will enable advanced targeted marketing messages. Broadband media services will create new classes of advertising such as on-demand marketing, where companies provide audio and video messages to consumers who express interest in a particular product. Automakers, for example, could offer one- or two-minute video clips demonstrating the features of specific new car models. Broadband media services will enable marketers to reach consumers near the time of the purchase consideration, with content targeted directly to the actual purchase decision-makers.

Some additional revenue-generating possibilities that operators and advertisers will enjoy are

• e-commerce. Transaction commissions on e-commerce via retailers on the system.
• real-estate charge. Monthly "rent" charged to each retailer on the system including links to retail sites and a number of pages on cache memory.
• network games. End-users or groups of end-users pay for getting access to the latest games over the network.
• sponsoring packages. Arrangements for retailers to be primary or secondary service providers in a service category (hub) with exclusive exposure possibilities on portal and hubs (fixed monthly or quarterly fees).
• pop-up specials. Pop-up on-screen banners with save, open, or close functionality. An interactive alternative to TV program sponsorships or as interactive add-ons to traditional commercials. Sales synergies with hard-drive space sales.
• Internet access. Sales margin on fast Internet access sold via the system.
• hard-drive space sales. "Rent" charged to advertisers for hard-disk space necessary to display products, product catalogues, or other direct-marketing pieces via the TV. Based on alternative costs of traditional direct-marketing distribution.
• subscription. Membership fees for access to extra or enhanced services.
• digital TV sales. Sales of broadcast entertainment.

So while high speed and shared access to Internet services, media delivery, and local networks provide endless possibilities for consumers, it can also create new revenue streams for operators, media companies, and service providers, through, among other things, multiplied use of access networks, branded media portals, interactive advertising, and e-commerce.
Broadband media services enable operators to capture part of households' new TV and video services and bundle them with traditional voice services, reducing customer churn and margin pressure. Everyone will benefit. Operators and service providers will provide access to services; network providers will generate revenues by maintaining and managing modular and scalable network enhancements and add-ons; content providers will create and license new content; advertisers will target customer user groups better than ever; and end-users will enjoy a new level of personalized services.

Figure 3. Example of broadband media services revenue-boosting potential for service providers with new service opportunities for existing customers.

Critical Issues in Broadband Media Services Deployment

While the many variables involved in creating commercially viable broadband media services are in place, there are still some challenges that need to be addressed and overcome by network and service providers. Building a scalable and reliable end-to-end network for on-demand entertainment is a large undertaking, and several technological and legal factors are involved in bringing large amounts of content to consumers.

Digital technology standards
While broadband media and IP standards are in rapid development and are given frequent enhancements, incompatible proprietary streaming-media technologies still exist. Similarly, not all content creators have adopted digital distribution strategies required for delivering broadband media services. This is changing quickly, however, as more large media conglomerates are signing deals with content providers to provide digital content to consumers.

Broadband content for mobile users
In the near future, third-generation mobile communication systems will extend the scope of today's Internet broadband solutions by introducing standardized broadband media services that target the mobile user's specific needs. Third-generation systems will provide high-quality streamed Internet content to the rapidly growing mobile market. These systems will offer value-added applications, supported by an underlying network that combines broadband media services with a range of unique mobile-specific services. Mobile application scenarios present many challenges, such as how to provide spectrum-efficient broadband media services over different radio-access networks to different types of end-user terminals and devices. Next-generation network architectures that fit seamlessly into third-generation mobile-communication systems are in development that will address the diversity and unique UI attributes of content on mobile devices.

Seamless content storage and retrieval
The amount of content involved in delivering broadband media services to businesses and consumers will be staggering. Research on indexing, storing, and creating retrieval mechanisms for multimedia archives inspires several directions for future developments and opportunities for additional revenues for entrepreneurial companies. For example, existing genre-classification and topic-detection methods require processing and analyzing large parts of a document, an even greater challenge when performed on live streams. New ways of indexing and categorizing network content will be created to improve organization and access to content. Scalability plays an important role in deploying such systems, given the amount of computation required for simultaneous processing of multiple streams. Fortunately, rapid progress in CRM networking is enabling deployment of new systems for tracking, disseminating, and billing customers for content consumption.

Who owns the content?
Content rights and distribution have become one of the hottest issues in the industry as a result of several well-publicized cases of copyright infringement lawsuits. The questions include the following: Who owns the distribution rights? Who owns access to the customer? How does digital content distribution affect the industry business model? need to be worked out and real-life implementation of advanced media services will require legal documentation on the limits and extent of responsibilities of each participant in the broadband media services value chain.

Other issues that are being addressed in broadband media services deployment include the following:

• Maintaining a balance between data compression and media quality. Enhancing MPEG standards as digital content develops by introducing new, better methods for compressing data size, yet maintain its quality.
• Access in remote areas. Ensuring widespread adoption of the client-server architecture to ensure network delivery of content across a broad geographic area, from cities to remote areas.
• IP security network security. Ensuring reliable, continuous security and authentication and verification of users in the network.