Chapter SevenObjectivesWAN EssentialsSlide 4PSTNSlide 6Slide 7X.25 and Frame RelaySlide 9ISDN (Integrated Services Digital Network)BRI (Basic Rate Interface)Slide 12PRI (Primary Rate Interface)Slide 14T-CarriersTypes of T-CarriersSlide 17T-Carrier ConnectivitySlide 19Slide 20DSLTypes of DSLSlide 23DSL ConnectivitySlide 25CableSlide 27Slide 28SONET (Synchronous Optical Network)Slide 30WAN Implementation: SpeedSlide 32WAN Implementation: ReliabilityWAN Implementation: SecurityWAN Implementation: Virtual Private Networks (VPNs)Remote ConnectivitySlide 37Dial-Up NetworkingSLIP and PPPChapter SummarySlide 41Slide 42Slide 43Chapter SevenChapter SevenWANs and Remote WANs and Remote ConnectivityConnectivityObjectivesObjectivesIdentify network applications that require WAN Identify network applications that require WAN technologytechnologyDescribe a variety of WAN transmission and Describe a variety of WAN transmission and connection methodsconnection methodsIdentify criteria for selecting an appropriate WAN Identify criteria for selecting an appropriate WAN topology, transmission method, and operating systemtopology, transmission method, and operating systemUnderstand the hardware and software requirements Understand the hardware and software requirements for connecting to a network via modemfor connecting to a network via modemInstall and configure simple remote connectivity for a Install and configure simple remote connectivity for a telecommunicating clienttelecommunicating clientWAN EssentialsWAN EssentialsWAN linkWAN linkConnection between one WAN site and Connection between one WAN site and another siteanother siteA WAN link is typically described as point-to-A WAN link is typically described as point-to-pointpointDedicated lineDedicated lineContinuously available link that is leased Continuously available link that is leased through another carrierthrough another carrierWAN EssentialsWAN EssentialsFigure 7-1: Differences in LAN and WAN connectivityPSTNPSTNPublic Switched Telephone NetworkPublic Switched Telephone NetworkRefers to the network of typical telephone Refers to the network of typical telephone lines and carrier equipment that service lines and carrier equipment that service most homesmost homesAlso called Also called plain old telephone service plain old telephone service (POTS)(POTS)PSTNPSTNA A dial-updial-up connection uses a PSTN or other line connection uses a PSTN or other line to access remote servers via modems at both to access remote servers via modems at both the source and destinationthe source and destinationThe The Federal Communications Commission Federal Communications Commission (FCC)(FCC) sets standards and policy for sets standards and policy for telecommunications transmission equipment in telecommunications transmission equipment in the United Statesthe United StatesThe place where two telephone systems meet is The place where two telephone systems meet is the the point of presencepoint of presence (POP)(POP)PSTNPSTNFigure 7-2: A typical PSTN connection to the InternetX.25 and Frame RelayX.25 and Frame RelayX.25X.25Analog, packet-switched LAN technology optimized for long-Analog, packet-switched LAN technology optimized for long-distance data transmissiondistance data transmissionFrame RelayFrame RelayUpdated, digital version of X.25 that also relies on packet switchingUpdated, digital version of X.25 that also relies on packet switchingFigure 7-3: A WAN using frame relayX.25 and Frame RelayX.25 and Frame RelaySVCs (switched virtual circuits)SVCs (switched virtual circuits)Connections established when parties need to Connections established when parties need to transmit, then dismantled once the transmission is transmit, then dismantled once the transmission is completecompletePVCs (private virtual circuits)PVCs (private virtual circuits)Connections established before data needs to be Connections established before data needs to be transmitted and maintained after transmission is transmitted and maintained after transmission is completecompleteCIR (committed information rate)CIR (committed information rate)Guaranteed minimum amount of bandwidth selected Guaranteed minimum amount of bandwidth selected when leasing a frame relay circuitwhen leasing a frame relay circuitISDN (Integrated Services Digital ISDN (Integrated Services Digital Network)Network)International standard for transmitting data International standard for transmitting data over digital linesover digital linesEstablished by the ITUEstablished by the ITUAll ISDN connections are based on two types All ISDN connections are based on two types of channels:of channels:The The B channelB channel is the “bearer” channel is the “bearer” channelThe The D channelD channel is the “data” channel is the “data” channelBRI (Basic Rate Interface)BRI (Basic Rate Interface)A variety of ISDN using two 64-Kbps bearer A variety of ISDN using two 64-Kbps bearer (B) channels and one 16-Kbps data (D) (B) channels and one 16-Kbps data (D) channel, as indicated by the following channel, as indicated by the following notation:notation:2B+D2B+DThrough Through bondingbonding, the two 64-Kbps , the two 64-Kbps channels can be combined to achieve an channels can be combined to achieve an effective throughput of 128-Kbpseffective throughput of 128-KbpsBRI (Basic Rate Interface)BRI (Basic Rate Interface)The The Network Termination 1 (NT1)Network Termination 1 (NT1) device connects device connects twisted-pair wiring at customer’s building with ISDN twisted-pair wiring at customer’s building with ISDN terminal terminal equipment (TE)equipment (TE) via RJ-11 or RJ-45 data jacks via RJ-11 or RJ-45 data jacksA A terminal adapter (TA)terminal adapter (TA) converts digital signals into analog converts digital signals into analog signals for use with ISDN phones and other analog devicessignals for use with ISDN phones and other analog devicesFigure 7-4: A BRI linkPRI (Primary Rate Interface)PRI (Primary Rate Interface)A variety of ISDN using 23 B channels and one A variety of ISDN using 23 B channels and one 64-Kbps D channel, as represented by the 64-Kbps D channel, as represented by the following notation:following notation:23B+D23B+DPRI links use same kind of equipment as BRI PRI links use same kind of equipment as BRI links, but require the services of an extra links, but require the services of an extra network termination device—called a network