TAILIEUCHUNG - Lecture Data communications and networks: Chapter 15 - Forouzan 

This chapter introduces you to wired LANs: Ethernet. This chapter introduces wired local area networks. A wired LAN, viewed as a link, is mostly involved in the physical and data link layers. We have devoted the chapter to the discussion of Ethernet and its evolution, a dominant technology today. | Chapter 15 Connecting LANs, Backbone Networks, and Virtual LANs Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 15. 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: 15. Figure Five categories of connecting devices 15. Figure A repeater connecting two segments of a LAN 15. A repeater connects segments of a LAN. Note 15. A repeater forwards every frame; it has no filtering capability. Note 15. A repeater is a regenerator, not an amplifier. Note 15. Figure Function of a repeater 15. Figure A hierarchy of hubs 15. A bridge has a table used in filtering decisions. Note 15. Figure A bridge connecting two LANs 15. A bridge does not change the physical (MAC) addresses in a frame. Note 15. Figure A learning bridge and the process of learning 15. Figure Loop problem in a learning bridge 15. Figure A system of connected LANs and its graph representation 15. Figure Finding the shortest paths and the spanning tree in a system of bridges 15. Figure Forwarding and blocking ports after using spanning tree algorithm 15. Figure Routers connecting independent LANs and WANs 15. 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: 15. In a bus backbone, the topology of the backbone is a bus. Note 15. Figure Bus backbone 15. In a star backbone, the topology of the backbone is a star; the backbone is just one switch.

• Quản trị mạng
• Data communications
• Lecture Data communications
• Physical layer
• Data link layer
• Connecting devices
• Backbone networks
• Business data communications
• Network criteria
• Data communications system
• Data communications networks
• Media access control
• Network models
• Network standards
• Application layer
• Application architectures
• Digital transmission
• Network and transport layers
• Transport layers
• Local area networks
• Traditional ethernet
• Wireless local area networks
• Wireless LANs
• Backbone network architectures
• Circuit switched networks
• Wide area networks
• Network security
• Risk assessment
• Network design
• Traditional network design
• Network management
• Configuration management