Networking Chapter 3 - Underlying Technology

Chapter 3 - Underlying Technology

• The chapter is about TCP/IP Protocol Suite, version 4.
• The book is written by Behrouz A. Forouzan.
• Copyright © The McGraw-Hill Companies, Inc.

Objectives

• Discuss the technology of dominant wired LANs, including traditional, fast, gigabit, and ten-gigabit Ethernet.
• Discuss the technology of wireless WANs, including IEEE 802.11 LANs and Bluetooth.
• Discuss the technology of point-to-point WANs, including 56K modems, DSL, cable modems, T-lines, and SONET.
• Discuss the technology of switched WANs, including X.25, Frame Relay, and ATM.
• Discuss the need and use of connecting devices such as repeaters, bridges, and routers.

Chapter Outline

• 3.1 Wired Local Area Network
• 3.2 Wireless LANs
• 3.3 Point-to-Point WANs
• 3.4 Switched WANs
• 3.5 Connecting Devices

3-1 Wired Local Area Networks

• A LAN is a computer network limited to a specific geographic area like a building or campus.
• Ethernet is the dominant LAN technology.
• Other technologies like token ring, token bus, FDDI, and ATM LANs have been used.

Topics Discussed in the Section

• IEEE Standards
• Frame Format
• Addressing
• Ethernet Evolution
• Standard Ethernet
• Fast Ethernet
• Gigabit Ethernet
• Ten-Gigabit Ethernet

Ethernet Frame

• Preamble: 56 bits of alternating 1s and 0s.
• SFD: Start frame delimiter, flag (10101011).
• Destination address: 6 bytes
• Source address: 6 bytes
• Length/type: 2 bytes
• Data and padding: variable length
• CRC: 4 bytes

Frame Lengths

• Minimum payload length: 46 bytes
• Maximum payload length: 1500 bytes
• Minimum frame length: 512 bits or 64 bytes
• Maximum frame length: 12,144 bits or 1518 bytes

Ethernet Address

• Formatted in hexadecimal notation (12 hexadecimal digits = 48 bits).
• Unicast addresses: start with 0.
• Multicast addresses: start with 1.
• Broadcast address: all digits are F's.

3-2 Wireless LANs

• Wireless communication is a fast-growing technology, demanding cable-free device connection.
• Wireless LANs use IEEE 802.11 technology, sometimes called wireless Ethernet.
• Bluetooth is a technology for small wireless LANs.

Topics Discussed in the Section

• IEEE 802.11
• MAC Sublayer
• Addressing Mechanism
• Bluetooth
• Basic service sets (BSSs)
• Extended service sets (ESSs)
• CSMA/CA flow diagram (CSMA/CA with NAV for preventing problems like hidden station problem and exposed station problem)

3-3 Point-to-Point WANs

• Point-to-point WAN connects two remote devices over a public network (like telephone network)
• Technologies discussed include traditional modems, DSL, cable modems, T-lines, and SONET.

Topics on 3-3 Point-to-Point WANs

• 64K Modems
• DSL Technology
• Cable Modem
• T-Lines
• SONET
• PPP

56k Modem

• Modems use PCM (pulse-code modulation) and telephone networks to transmit data.

ADSL

• Asymmetric technology designed for residential use, not suitable for businesses.

Cable Modem

• Data, video, and data are transmitted over the cable frequencies.

T-Lines Types

• T-1
• T-3

SONET

• Synchronous Optical network
• Provides high-speed transmission using fiber optics.

3-4 Switched WANs

• Backbone networks in the internet use switched WANs.
• WANs cover large areas and access points for the end users. Networks use point-to-point connections using switches and port connectors.
• The technology differs from LAN technology and the main sections are X.25, Frame Relay and ATM.

Topics Discussed in the Section

• X.25
• Frame Relay
• ATM

ATM (Asynchronous Transfer Mode)

• Cell networks used as the basic data exchange unit.
• Cell as a small and fixed-size block of information.
• ATM multiplexing and architecture
• Virtual circuits uniquely defined by VPI and VCI pairs, and the layers.

3-5 Connecting Devices

• LANs and WANs typically need connecting devices to work with one another.
• Repeaters (or hubs), bridges (or two-layer switches), and routers (or three-layer switches) enable connection to the internet

Topics Discussed in the Section

• Repeaters
• Bridges
• Routers

Repeater

• Repeater forwards every bit, it has no filtering capability

Bridge

• Bridge has a table for filtering decisions
• Bridge does not change the physical (MAC) addresses in a frame.

Router

• A router is a three-layer (physical, data link, and network) device.
• A repeater or a bridge connects segments of a LAN.
• A router connects independent LANs or WANs to create an internetwork.

Explore the TCP/IP Protocol Suite and its various applications in wired and wireless networks. This chapter discusses technologies including Ethernet, IEEE 802.11, and different types of WANs, along with the use of connecting devices like routers and bridges. Gain a deeper understanding of the underlying technologies that support modern computer networks.