Hiperlan/2. Universal Serial Bus (USB). Universal Plug-and-Play (UPnP)

HIPERLAN/2 is a broadband wireless LAN technology that operates at rates as high as 54 Mbps in the 5-GHz frequency band. HIPERLAN/2 is a European proposition supported by the European Telecommunications Standards Institute (ETSI) and developed by the Broadband Radio Access Networks (BRAN) team. HIPERLAN/2 is designed in a flexible way so as to be able to connect with 3G mobile networks, IP networks, and ATM networks. It can be also used as a private wireless LAN network.

A basic characteristic of this protocol is its ability to support multimedia traffic i.e., data, voice, and video providing quality of service. The physical layer uses OFDM, a technique that is efficient in the transmission of analog signals in a noisy environment. The MAC protocol uses a dynamic TDMA/TDD scheme with centralized control.

Universal Serial Bus (USB). As most PCs today have at least 2 USB ports, accessible from outside the case, connecting new USB devices is a very simple Plug-n-Play process. Moreover, USB is able to cover limited power requirements of the devices, in many cases eliminating the need for additional power cables. USB 1.1 provides both asynchronous data transfer and isochronous streaming channels for audio/video streams, voice telephony, and multimedia applications, and bandwidth up to 12 Mbps adequate even for compressed video distribution.

USB v2.0 transfers rates up to 460-480 Mbps, about 40 times faster than vl.l, covering more demanding consumer electronic devices such as digital cameras and DVD drives. USB may not dominate in the Consumer Electronics Networks in the short term, but it will certainly be among the major players.

Universal Plug-and-Play (UPnP). UPnP aims to extend the simplicity and auto-configuration features from device PnP to the entire network, enabling the discovery and control of networked devices and services. UPnP in supported and promoted by the UPnP forum. UPnP is led by Microsoft, while some of the major UPnP forum members are HP, Honeywell, Intel, Mitsubishi, and Philips.

The scope of UPnP is large enough to encompass many existing, as well as new and exciting, consumer electronics networking and automation scenarios including home automation/security, printing and imaging, audio/video entertainment, kitchen appliances, and automobile networks.

In order to ensure interoperability between vendor implementations and gain maximum acceptance in the existing networked environment, UPnP leverages many existing, mature, standard protocols used on the Internet and on LANs like IP, HTTP, and XML.

UPnP enables a device to dynamically join a network, obtain an IP address, convey its capabilities, and be informed about the presence and capabilities of other devices. Devices can automatically communicate with each other directly without any additional configuration. UPnP can be used over most physical media including Radio Frequency (RF, wireless), phone line, power line, IrDA, Ethernet, and IEEE 1394. In other words, any medium that can be used to network devices together can enable UPnP. Moreover, other technologies (e.g., HAVi, CeBus, orXlO) could be accessed via a UPnP bridge or proxy, providing for complete coverage.

UPnP vendors, UPnP Forum Working Committees, and the UPnP Device Architecture layers define the highest- layer protocols used to implement UPnP. Based on the device architecture specification, the working committees define information global to specific device types such as VCRs, HVAC systems, dishwashers, and other appliances. UPnP device vendors define the data specific to their devices such as the model name, URL, and so on.

DSL and Cable Modems. Digital subscriber line (DSL) is a modem technology that increases the digital speed of ordinary telephone lines by a substantial factor over common V.34 (33,600 bps) modems. DSL modems may provide symmetrical or asymmetrical operation. Asymmetrical operation provides faster downstream speeds and is suited for Internet usage and video on demand, where the heaviest transmission requirement is from the provider to the customer.

DSL has taken over the home network market. Chip sets will combine home networking with V.90 and ADSL modem connectivity into one system that uses existing in-home telephone wiring to connect multiple PCs and peripherals at a speed higher than 1 Mbps.

A cable modem is another option that should be considered in home network installations. Cable modem service is more widely available and significantly less expensive than DSL in some countries. Cable modems allow much faster Internet access than dial-up connections. As coaxial cable provides much greater bandwidth than telephone lines, a cable modem allows downstream data transfer speeds up to 3 Mbps.

This high speed, combined with the fact that millions of homes are already wired for cable TV, has made the cable modem one of the top broadband contenders. The advent of cable modems also promises many new digital services to the home, including video on demand, Internet telephony and videoconferencing, and interactive shopping and games.

At first glance, xDSL (i.e., DSL in one of the available varieties) appears to be the frontrunner in the race between cable modems and DSL. After all, it can use the phone wire that is already in place in almost every home and business. Cable modems require a television cable system, which is also in many homes and businesses but does not have nearly the same penetration as basic telephone service. One important advantage that cable modem providers do have is a captive audience. All cable modem subscribers go through the same machine room in their local area to get Internet access.

In contrast to cable modem service, xDSL’s flexibility and multi vendor support is making it look like a better choice for IT departments that want to hook up telecommuters and home offices, as well as for extranet applications. Any ISP will be able to resell xDSL connections, and those connections are open to some competition because of the Telecommunications Act of 1996. The competitive multi-vendor environment has led to a brisk commodity market for xDSL equipment and has made it a particularly attractive and low-cost pipe. Although new services are sure to be spawned by all that bandwidth, xDSL providers are able to depend on the guaranteed captive audience of their cable modem counterparts.

Fiber Optics. Fiber optics at home have also been evaluated in the literature. The well-known advantages of fiber, such as increased bandwidth, immunity to electromagnetic noise, security from wiretaps, and ease of installation, compete with its disadvantages, such as higher cost, difficulty in splicing, and requirement of an alternate power supply. A standard for a fiber optic CEBus (FOBus) has been developed.

One of the major drives behind the use of fiber optics is the ability to carry multimedia traffic in an efficient way. As telecommunication companies are planning to bring fiber to the home, a fiber optic network in the house will make the Internet working with places outside the house cost effective and convenient. Connection with multimedia libraries or with other places offering multimedia services will be easily accomplished to the benefits of the house occupants, especially students of any age who will be able to access, and possibly download and manage, these vast pools of information.

Several minimum requirements of a FOBus are set forth. In terms of service, the FOBus should provide the following services:
- Voice, audio, interactive, bulk data, facsimile, and video;
- One-way, two-way, and broadcast connectivity;

- Transport of continuous and bursty traffic;
- Interfaces to external networks and consumer products; and Multiple data channels and a single, digital control channel.

The network should meet the following physical requirements:
- Low installation costs and ease of installation;
- High reliability;
- Easy attachment of new devices;
- No interruption of service while a new node is being connected; and
- Access to the network via taps in each room.

The FOBus standard should also have a layered architecture in which layers above the physical layer are identical to the corresponding CEBus layers in other media.

Some of the applications of a fiber optic network in the home that will drive the design of the fiber optic home network are: the connection to emerging all-fiber networks, which will provide high-quality, high-bandwidth audio/ visual/data services for entertainment and information; fiber network connection to all-fiber telephone networks to allow extended telephone services such as ISDN, videotelephone, and telecommuting; transport of high-quality audio/video between high-bandwidth consumer devices such as TVs and VCRs; and transport of control and data signals for a high degree of home automation and integration.

 






Date added: 2024-02-27; views: 135;


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