9-1 Chapter 9 - Communication

Department of Information Technology, Radford University ITEC 352 Computer Organization

Principles of Computer ArchitectureMiles Murdocca and Vincent Heuring

Chapter 9: Communication

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Department of Information Technology, Radford University ITEC 352 Computer Organization

Chapter Contents

9.1 Modems

9.2 Transmission Media

9.3 Network Architecture: Local Area Networks

9.4 Communication Errors and Error Correcting Codes

9.5 Network Architecture: The Internet

9.6 Case Study: Asynchronous Transfer Mode

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Department of Information Technology, Radford University ITEC 352 Computer Organization

Modem Communication

• Communication over a telephone line with modems:

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Department of Information Technology, Radford University ITEC 352 Computer Organization

Modulation Schemes• Three common forms of modulation:

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Pulse Code Modulation• Conversion of an analog signal into a PCM binary sequence:

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Department of Information Technology, Radford University ITEC 352 Computer Organization

Ideal vs. Transmitted Waves

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Transmission Media

• Transmisson media. (a) Two-wire open lines; (b) twisted-pair lines; (c) coaxial cable; (d) optical fiber; (e)satellites.

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The Seven Layers of the OSI Model

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A Few Network Topologies• (a) Bus; (b) ring; and (c) star network topologies.

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Parity• Even parity bits are assigned to a few ASCII characters:

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Check Bits• Check bits for a single error correcting ASCII code:

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SEC coded ‘a’

• Format for a single error correcting ASCII code:

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SEC Coded ‘d’

• Parity computation for an ASCII character in an SEC code:

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3-Bit SEC Hypercube• Hamming distance relationships among three-bit codewords.

Valid codewords are 000 and 111. The remaining codewords represent errors.

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LRC and VRC Checking

• Combined LRC and VRC checking. Checksum bits form even parity for each column.

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Cyclic Redundancy Checking

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Internet Protocol Stack• Layering in the TCP/IP protocol suite:

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IPv4 Address Classes

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Encapsulation• Encapsulation in the TCP/IP protocol suite:

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Department of Information Technology, Radford University ITEC 352 Computer Organization

Hub vs. Router vs.

Switch

• Configurations shown for (a) a hub; (b) a router; and (c) a switch.

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Self-Routing Switch

• A 44 self-routing switch based on the bubblesort algorithm:

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TDM vs. ATM• (a) Time division multiplexing vs. (b) asynchronous transfer mode.

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Format of an ATM Packet• Format of an ATM packet. (a) User-to-network interface (UNI) format; and (b) network-to-network interface

(NNI) format.

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Simple ATM Network