Figure 7-2: Leased Line Networks for Voice and Data eased Line data Network Site a Site B 田 outer OC3 Leased Line Router Leased T1 Line Leased line data Networks Have a 56 kbps Site C Router at each Site Leased Line Router Leased 56 kbps Ine Leased Router/56 kbps Line Leased Router Line Site D ite e 7-11
7-11 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 Data Network Router Router Router Router Router Leased Line Data Networks Have a Router at Each Site
Figure 7-3: Full Mesh and Pure Hub-and-Spoke Topologies for Leased Line Data Networks Site A Full Mesh Topology Site B 吧日 田中 OC 3 Leased Line In a full mesh topology there is a leased line eased between each pair of sitesLine Highly reliable eased Line Leased ighly expensive Line LEaSEE Line Site c Site D 12
7-12 Figure 7-3: Full Mesh and Pure Hub-and-Spoke Topologies for Leased Line Data Networks Full Mesh Topology OC3 Leased Line T1 Leased Line Site A Site B Site C Site D T1 Leased Line T3 Leased Line T3 Leased Line In a full mesh topology, there is a leased line between each pair of sites Highly reliable Highly expensive
Figure 7-3: Full Mesh and Pure Hub-and-Spoke Topologies for Leased Line Data Networks Site A Pure Hub-and-Spoke Topology Site B In a pure hub-and-spoke 田 o topology, there is only one leased line from the hub site to each other site Very inexpensive Very unreliable Leased Leased Line Site D Few companies use either of these extreme topologies They have some backup links uu site C 7-13
7-13 Figure 7-3: Full Mesh and Pure Hub-and-Spoke Topologies for Leased Line Data Networks Pure Hub-and-Spoke Topology OC3 Leased Line Site A Site B Site C Site D T3 Leased Line T3 Leased Line In a pure hub-and-spoke topology, there is only one leased line from the hub site to each other site. Very inexpensive. Very unreliable. Few companies use either of these extreme topologies. They have some backup links
Test Your understanding Page 314 2 Page 317 3 7-14
7-14 • Test Your understanding • Page 314 • 2 • Page 317 • 3
Figure 7-4: Leased Line Speeds North American Digital Hierarchy Line Speed Typical Transmission Medium 56 kbps 56 kbps 2-Pair Data-Grade UTP T1 1.544 Mbps 2-Pair Data-Grade UTP 56 kbps leased lines are hardly used today because they are so slow T1 lines are very widely used because they are in the speed range of greatest corporate demand- 128 kbps to a few megabits per second 7-15
7-15 Figure 7-4: Leased Line Speeds Line Speed Typical Transmission Medium 56 kbps 56 kbps 2-Pair Data-Grade UTP T1 1.544 Mbps 2-Pair Data-Grade UTP North American Digital Hierarchy 56 kbps leased lines are hardly used today because they are so slow. T1 lines are very widely used because they are in the speed range of greatest corporate demand— 128 kbps to a few megabits per second