[ Pobierz całość w formacie PDF ]
.Another security option in the Access Control tab isuser-level access, which is used to limit resource access byuser name.This function eliminates the need to rememberpasswords for each shared resource.Each user simply logsonto the network with a unique name and password; the net-work administrator governs who can do what on the net-work.However, this requires the computers to be part of alarger network with a central server perhaps running 248 PEER-TO-PEER NETWORKSFigure P-7 Choosing share-level access allows the user topassword-protect each shared resource.Windows NT/2000 server that maintains the access-control list for the whole network.Since Windows 95/98 andWindows NT/2000 workstations support the same protocols,Windows 95/98 computers can participate in a WindowsNT/2000 server domain.Peer services can be combined with standard client-servernetworking.For example, if a Windows 95/98 computer is amember of a Windows NT/2000 network and has a color printerto share, the resource owner can share that printer with othercomputers on the network.The server s access-control listdetermines who is eligible to share resources.Once the networking infrastructure is in place, the NIC ofeach computer is individually connected to a hub with PEER-TO-PEER NETWORKS 249Figure P-8 Aprinter can be configured for sharing.Category 5 cable or wirelessly via the access point.Thiscable has connectors on each end that insert into the RJ45jacks of the hub and NICs.For small networks, the hub usuallywill be manageable with the Simple Network ManagementProtocol (SNMP), so no additional software is installed.Oncethe computers are properly configured and connected to thehub, the network is operational.SummaryPeer-to-peer networking is an inexpensive way for small com-panies and households to share resources among a small 250 PEER-TO-PEER NETWORKSFigure P-9 Aprinter can be password-protected if necessary.group of computers.This type of network provides most of thesame functions as the traditional client-server network,including the ability to run network versions of popular soft-ware packages.Peer-to-peer networks also are easy toinstall.Under ideal conditions, installation of the cards, soft-ware, hub, and cabling for five users would take only a fewhours.Wireless links provide the advantage of mobilitywithin the home or office, allowing a notebook to be used inany room.See alsoHomeRFWireless FidelityWireless LANs PERSONAL ACCESS COMMUNICATIONS SYSTEMS 251PERSONAL ACCESS COMMUNICATIONSPERSONAL ACCESS COMMUNICATIONSSYSTEMSSYSTEMSPersonal Access Communications Systems (PACS) is a stan-dard adopted by ANSI for Personal Communication Services(PCS).Adopted in June 1995, PACS provides an approach forimplementing PCS in North America that is fully compatiblewith the local exchange telephone network and interopera-ble with existing cellular systems.Based on the PersonalHandyphone System (PHS) developed in Japan and theWireless Access Communications System (WACS) developedby Bellcore (now known as Telcordia Technologies), PACS isdesigned to support mobile and fixed applications in the1900-MHz frequency range.It promises low installation andoperating costs while providing very-high-quality voice anddata services.In the United States, trials of PACS equip-ment began in 1995, and equipment rollout began in 1996.Most of the standards including up-banded versions ofCDMA, TDMA, and GSM look like cellular systems in thatthey have high transmit powers and receivers designed forthe large delay spreads of the macrocellular environmentand typically use low-bit-rate voice coders (vocoders).PACSfills the niche between these classes of systems, providinghigh-quality services, high data capability, and high userdensity in indoor and outdoor microcellular environments.PACS equipment is simpler and less costly than macrocellu-lar systems yet more robust than indoor systems [ Pobierz całość w formacie PDF ]
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.Another security option in the Access Control tab isuser-level access, which is used to limit resource access byuser name.This function eliminates the need to rememberpasswords for each shared resource.Each user simply logsonto the network with a unique name and password; the net-work administrator governs who can do what on the net-work.However, this requires the computers to be part of alarger network with a central server perhaps running 248 PEER-TO-PEER NETWORKSFigure P-7 Choosing share-level access allows the user topassword-protect each shared resource.Windows NT/2000 server that maintains the access-control list for the whole network.Since Windows 95/98 andWindows NT/2000 workstations support the same protocols,Windows 95/98 computers can participate in a WindowsNT/2000 server domain.Peer services can be combined with standard client-servernetworking.For example, if a Windows 95/98 computer is amember of a Windows NT/2000 network and has a color printerto share, the resource owner can share that printer with othercomputers on the network.The server s access-control listdetermines who is eligible to share resources.Once the networking infrastructure is in place, the NIC ofeach computer is individually connected to a hub with PEER-TO-PEER NETWORKS 249Figure P-8 Aprinter can be configured for sharing.Category 5 cable or wirelessly via the access point.Thiscable has connectors on each end that insert into the RJ45jacks of the hub and NICs.For small networks, the hub usuallywill be manageable with the Simple Network ManagementProtocol (SNMP), so no additional software is installed.Oncethe computers are properly configured and connected to thehub, the network is operational.SummaryPeer-to-peer networking is an inexpensive way for small com-panies and households to share resources among a small 250 PEER-TO-PEER NETWORKSFigure P-9 Aprinter can be password-protected if necessary.group of computers.This type of network provides most of thesame functions as the traditional client-server network,including the ability to run network versions of popular soft-ware packages.Peer-to-peer networks also are easy toinstall.Under ideal conditions, installation of the cards, soft-ware, hub, and cabling for five users would take only a fewhours.Wireless links provide the advantage of mobilitywithin the home or office, allowing a notebook to be used inany room.See alsoHomeRFWireless FidelityWireless LANs PERSONAL ACCESS COMMUNICATIONS SYSTEMS 251PERSONAL ACCESS COMMUNICATIONSPERSONAL ACCESS COMMUNICATIONSSYSTEMSSYSTEMSPersonal Access Communications Systems (PACS) is a stan-dard adopted by ANSI for Personal Communication Services(PCS).Adopted in June 1995, PACS provides an approach forimplementing PCS in North America that is fully compatiblewith the local exchange telephone network and interopera-ble with existing cellular systems.Based on the PersonalHandyphone System (PHS) developed in Japan and theWireless Access Communications System (WACS) developedby Bellcore (now known as Telcordia Technologies), PACS isdesigned to support mobile and fixed applications in the1900-MHz frequency range.It promises low installation andoperating costs while providing very-high-quality voice anddata services.In the United States, trials of PACS equip-ment began in 1995, and equipment rollout began in 1996.Most of the standards including up-banded versions ofCDMA, TDMA, and GSM look like cellular systems in thatthey have high transmit powers and receivers designed forthe large delay spreads of the macrocellular environmentand typically use low-bit-rate voice coders (vocoders).PACSfills the niche between these classes of systems, providinghigh-quality services, high data capability, and high userdensity in indoor and outdoor microcellular environments.PACS equipment is simpler and less costly than macrocellu-lar systems yet more robust than indoor systems [ Pobierz całość w formacie PDF ]