Ch15
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This document discusses different types of connecting devices used in computer networks, including passive hubs, active hubs, bridges, switches, routers and gateways. It also covers backbone networks that allow multiple LANs to be connected using bus or star topologies. Finally, it describes virtual LANs (VLANs) which use software rather than physical wiring to configure local area networks and control communication between switches.
Ch15
- 1. Chapter 15 Connecting LANs, Backbone Networks, and Virtual LANs Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 2. 15-1 CONNECTING DEVICES In this section, we divide connecting devices into five different categories based on the layer in which they operate in a network. Passive Hubs Active Hubs Bridges Two-Layer Switches Routers Three-Layer Switches Gateways Topics discussed in this section:
- 3. Figure 15.1 Five categories of connecting devices
- 4. Figure 15.2 A repeater connecting two segments of a LAN
- 5. A repeater connects segments of a LAN. Note
- 6. A repeater forwards every frame; it has no filtering capability. Note
- 7. A repeater is a regenerator, not an amplifier. Note
- 8. Figure 15.3 Function of a repeater
- 9. Figure 15.4 A hierarchy of hubs
- 10. A bridge has a table used in filtering decisions. Note
- 11. Figure 15.5 A bridge connecting two LANs
- 12. A bridge does not change the physical (MAC) addresses in a frame. Note
- 13. Figure 15.6 A learning bridge and the process of learning
- 14. Figure 15.7 Loop problem in a learning bridge
- 15. Figure 15.8 A system of connected LANs and its graph representation
- 16. Figure 15.9 Finding the shortest paths and the spanning tree in a system of bridges
- 17. Figure 15.10 Forwarding and blocking ports after using spanning tree algorithm
- 18. Figure 15.11 Routers connecting independent LANs and WANs
- 19. 15-2 BACKBONE NETWORKS A backbone network allows several LANs to be connected. In a backbone network, no station is directly connected to the backbone; the stations are part of a LAN, and the backbone connects the LANs. Bus Backbone Star Backbone Connecting Remote LANs Topics discussed in this section:
- 20. In a bus backbone, the topology of the backbone is a bus. Note
- 21. Figure 15.12 Bus backbone
- 22. In a star backbone, the topology of the backbone is a star; the backbone is just one switch. Note
- 23. Figure 15.13 Star backbone
- 24. Figure 15.14 Connecting remote LANs with bridges
- 25. A point-to-point link acts as a LAN in a remote backbone connected by remote bridges. Note
- 26. 15-3 VIRTUAL LANs We can roughly define a virtual local area network (VLAN) as a local area network configured by software, not by physical wiring. Membership Configuration Communication between Switches IEEE Standard Advantages Topics discussed in this section:
- 27. Figure 15.15 A switch connecting three LANs
- 28. Figure 15.16 A switch using VLAN software
- 29. Figure 15.17 Two switches in a backbone using VLAN software
- 30. VLANs create broadcast domains. Note