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Lecture Business data communications: Chapter 10 - Behrouz A. Forouzan

Chapter 10 - Local area networks part 2: Wireless and Virtual LANs. After reading this chapter, the reader should be able to: Understand the different transmission techniques used in wireless LANs, understand the main characteristics of IEEE 802.11 wireless LANs, understand the applications of IEEE 802.11, understand the characteristics of 802.15 LANs and the Bluetooth technology that implements this standard. | Chapter 10 Local Area Networks Part 2: Wireless and Virtual LANs Understand the different transmission techniques used in wireless LANs. Understand the main characteristics of IEEE 802.11 wireless LANs. Understand the applications of IEEE 802.11. Understand the characteristics of 802.15 LANs and the Bluetooth technology that implements this standard. After reading this chapter, the reader should be able to: OBJECTIVES OBJECTIVES (continued) Understand the applications and rationale for VLANs. Understand the concept of virtual LANs. WIRELESS LANs 10.1 Figure 10-1 ISM bands Figure 10-2 FHSS Figure 10-3 DSSS IEEE 802.11: RF LANs 10.2 Figure 10-4 BSS Figure 10-5 ESS Technical Focus: Portable versus Mobile In networking two terms are used to define nonstationary devices: portable and mobile. The term portable means that a device may move from one location to another, but it remains in a fixed place when in use. The term mobile means that the station can move during operation. . | Chapter 10 Local Area Networks Part 2: Wireless and Virtual LANs Understand the different transmission techniques used in wireless LANs. Understand the main characteristics of IEEE 802.11 wireless LANs. Understand the applications of IEEE 802.11. Understand the characteristics of 802.15 LANs and the Bluetooth technology that implements this standard. After reading this chapter, the reader should be able to: OBJECTIVES OBJECTIVES (continued) Understand the applications and rationale for VLANs. Understand the concept of virtual LANs. WIRELESS LANs 10.1 Figure 10-1 ISM bands Figure 10-2 FHSS Figure 10-3 DSSS IEEE 802.11: RF LANs 10.2 Figure 10-4 BSS Figure 10-5 ESS Technical Focus: Portable versus Mobile In networking two terms are used to define nonstationary devices: portable and mobile. The term portable means that a device may move from one location to another, but it remains in a fixed place when in use. The term mobile means that the station can move during operation. Technical Focus: Hidden Node Problem In a wired Ethernet, when a station sends a frame, every station connected to the shared medium senses (hears) the signal; stations are not hidden (electronically) from each other. On the other hand, in a wireless network, two stations may be separated from each other by a physical barrier (such as a wall). They are hidden (electronically) from each other. In this case, both of these stations may start sending a frame at the same time without sensing the signal coming from the other station. In other words, a collision may occur without either station detecting it. This means that the CSMA/CD access method, which is based on the detection of a collision by the sender, does not work here. Technical Focus: Wireless LAN Addressing The addressing mechanism in a wireless LAN is more complicated than in a wired LAN. In a wireless LAN a frame may travel from a station to another station in the same BSS, or from a station in one BSS to another station in another