6-1

Parte 7Comunicação

6-2

Bibliografia

[1] Miles J. Murdocca e Vincent P. Heuring, “Introdução à Arquitetura de Computadores”

[2] Andrew S. Tanenbaum, “Computer Networks”

6-3

Modem Communication

• Communication over a telephone line with modems:

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-4

Modulation Schemes

• Three common forms of modulation:

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-5 Pulse Code Modulation

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

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-6

Ideal vs. Transmitted Waves

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-7 Transmission Media

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

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-8 The Seven Layers of the OSI Model

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-9

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

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-10 Parity

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

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-11

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

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-12

SEC coded ‘a’

• Format for a single error correcting ASCII code:

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-13

SEC Coded ‘d’

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

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-14

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

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

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-15

LRC and VRC Checking

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

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-16

Cyclic Redundancy Checking

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-17

Internet Protocol Stack

• Estrutura em camadas da pilha TCP/IP:

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-18

Classes de Endereços IPv4

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-19

Encapsulação• Encapsulamento na pilha TCP/IP:

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-20

Hub x

Roteador x

Switch

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-21

Self-Routing Switch

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

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-22

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

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-23

Formato da Célula ATM• (a) User-to-network interface (UNI) format; and (b) network-to-network interface (NNI) format.

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring

6-24

Uma Rede ATM Simples

Principles of Computer Architecture by M. Murdocca and V. Heuring © 1999 M. Murdocca and V. Heuring