Wide area networks (WANS) Chapte Updated January 2009 XU Zhengchuan Fudan University
Wide Area Networks (WANs) Chapter 7 Updated January 2009 XU Zhengchuan Fudan University
Orientation Single Networks Layers 1 and 2(so osI standards dominate) Chapters 4-7: Local to long-distance for single networks Chapter 4: Wired Ethernet LANS Chapter 5: Wireless LANS WLANs) Chapter 6: Telecommunications(and Internet Access Chapter 7: Wide Area Networks (WANs) Chapter 8: TCP/IP Internetworking To link multiple single networks 7-2
7-2 Orientation • Single Networks – Layers 1 and 2 (so OSI standards dominate) – Chapters 4-7: Local to long-distance for single networks • Chapter 4: Wired Ethernet LANs • Chapter 5: Wireless LANs (WLANs) • Chapter 6: Telecommunications (and Internet Access) • Chapter 7: Wide Area Networks (WANs) • Chapter 8: TCP/IP Internetworking – To link multiple single networks
WAN Essentials
WAN Essentials
Figure 7-1: Wide Area Networks WANS) Wide Area Networks(WANs) Single networks that connect different sites So Layer 1 and Layer 2 operation WAN Purposes Internet access( Chapter 6) Link sites within the same corporation Provide remote access to individuals who are off site 7-4
7-4 Figure 7-1: Wide Area Networks (WANs) • Wide Area Networks (WANs) – Single networks that connect different sites – So Layer 1 and Layer 2 operation • WAN Purposes – Internet access (Chapter 6) – Link sites within the same corporation – Provide remote access to individuals who are off site
Figure 7-1: Wide Area Networks WANS) WANs are characterized by high cost and low Speeds High cost per bit transmitted compared to LaNs Consequently, lower speeds(most commonly 128 kbps to a few megabits per second) This speed usually is aggregate throughput shared by many users Much slower than LAN speeds (100 Mbps to 1 Gbps to the desktop 7-5
7-5 Figure 7-1: Wide Area Networks (WANs) • WANs are Characterized by High Cost and Low Speeds – High cost per bit transmitted compared to LANs – Consequently, lower speeds (most commonly 128 kbps to a few megabits per second) • This speed usually is aggregate throughput shared by many users – Much slower than LAN speeds (100 Mbps to 1 Gbps to the desktop)
Figure 7-1: Wide Area Networks WANS) Carriers Beyond their physical premises, companies must use the services of regulated carriers for transmission Companies do not have rights of way to lay wires beyond their premises Customers are limited to whatever services the carriers provide Prices for carrier services change abruptly and without technological reasons Prices and service availability vary widely from country to country 7-6
7-6 Figure 7-1: Wide Area Networks (WANs) • Carriers – Beyond their physical premises, companies must use the services of regulated carriers for transmission • Companies do not have rights of way to lay wires beyond their premises – Customers are limited to whatever services the carriers provide – Prices for carrier services change abruptly and without technological reasons – Prices and service availability vary widely from country to country
Page 313 Test Your understanding
7-7 • Page 313 • Test Your understanding • 1
Leased Line Networks
Leased Line Networks
Leased Lines: Recap Leased line characteristics Point-to-point circuits Always on High speeds: 64 kbps (rare) to several gigabits per second Leased for a minimum period of time Usually offered by telephone companies 7-9
7-9 Leased Lines: Recap • Leased Line Characteristics – Point-to-point circuits – Always on – High speeds: 64 kbps (rare) to several gigabits per second – Leased for a minimum period of time – Usually offered by telephone companies
Figure 7-2: Leased Line Networks for Voice and Data eased Line voice Network Site A Site B OC3 Leased Line PBⅩ PBX Leased T1 Line Leased Leased line voice Networks Have a 56 kbps Site C Leased PBX at each Site Line 56 kbps PBX Leased Ine Leased 56 kbps Line PBX PBX Leased Line Site D Site e 7-10
7-10 Figure 7-2: Leased Line Networks for Voice and Data OC3 Leased Line T1 Leased Line T1 Leased Line T3 Leased Line 56 kbps Leased Line 56 kbps Leased Line 56 kbps Leased Line Site A Site B Site D Site E Site C Leased Line Voice Network PBX PBX PBX PBX PBX Leased Line Voice Networks Have a PBX at Each Site
