Approaches To Network Communications

  • Uploaded by: akirank1
  • 0
  • 0
  • May 2020
  • PDF

This document was uploaded by user and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Report DMCA


Overview

Download & View Approaches To Network Communications as PDF for free.

More details

  • Words: 645
  • Pages: 12
Approaches to Network Communications • Circuit-Switched – Connection Oriented – Form dedicated connection between 2 points – U.S. Telephone System

• Packet_Switched – – – – –

Connectionless Data to be transferred broken into small packets Multiplexed onto high capacity systems Carries a few hundred(s) data usually Advantage: Multiple communications occur concurrently – Disadvantage: Network overload causes throughput decrease

© MMII JW Ryder

CS 428 Computer Networks

1

WAN/LAN • Fundamental difference between large and small spanning geographical distance networks • 2 Categories, no formal split • Wide Area Networks, long haul networks – Slower speeds, greater delays – Typical speeds 56Kbps to 155 Mbps

© MMII JW Ryder

CS 428 Computer Networks

2

WAN/LAN • Local Area Network – Highest speed, sacrifice long distance – Single building, small campus – Typical speeds 10 Mbps to 2 Gbps

• LAN - Each computer connects directly to physical transport medium via network interface device © MMII JW Ryder

CS 428 Computer Networks

3

WAN/LAN • WAN - Network usually consists of a series of interconnected intermediate node routers interconnected by communication lines and modems • Extending network means adding another packet switch • Connect a new computer to WAN means connecting it to a packet switch

© MMII JW Ryder

CS 428 Computer Networks

4

WAN/LAN • Adding a new switch adds delay along route • Software hides details of hardware on different packet switches – Hardware independent transport

© MMII JW Ryder

CS 428 Computer Networks

5

Network Hardware Addresses • Each hardware technology has an addressing mechanism • Specifies destination of packet • Every computer on a network is assigned a unique address – Usually an integer

• Destination address field contained in each packet – Same location in all packets

• Sender must know destination address © MMII JW Ryder

CS 428 Computer Networks

6

Ethernet Technology • Packet-switched LAN technology – Xerox Palo Alto Research Center (PARC) in early ‘70s

• See Figure 2.1 on page 20 • Connection between computer and co-axial (coax) called a transceiver • See Figure 2.2 on page 21 • Pin hole in ether = tap • Connections to Ethernet have 2 major components © MMII JW Ryder

CS 428 Computer Networks

7

Transceiver/Host Interface • Host Adapter • Transceiver – Connects to center wire and braided shield – Sensing and sending signals on the ether

• Host Interface – Plugs into the computer’s bus on motherboard – Connected to transceiver by cable called Attachment Unit Interface (AUI)

• Oldest form of Ethernet technology (Thick-Wire Ethernet) • See Figure 2.4 on page 23 © MMII JW Ryder

CS 428 Computer Networks

8

Thin-Wire Ethernet • First improvement, better access, lower cost • Thinnet • Thinner coax cable, less expensive, more flexible • Thinner cable more susceptible to electronic interference (noise), shorter distances, fewer computers © MMII JW Ryder

CS 428 Computer Networks

9

Thinnet • Replace high cost transceivers with digital circuitry inside of host interfaces • Direct connection from computer to ether • Connects direction from one computer to another • See Figure 2.5 on page 24 • BNC Connectors, T’s in the back plugged into host adapter – Show on board

© MMII JW Ryder

CS 428 Computer Networks

10

Twisted Pair Ethernet • No longer need for shield of coax • Ethernet access with pair of unshielded copper wires similar to telephone wires • Further reduces cost, protects other users on network when someone disconnects • 10Base-T wiring connects computers via an Ethernet Hub • See Figure 2.6 on page 25

© MMII JW Ryder

CS 428 Computer Networks

11

Hub • Electronic device that simulates signals of Ethernet • Computers must be < 100m away • Requires power • Intelligent vs. Dumb Hub • Connection to hub acts same as host adapter to transceiver

© MMII JW Ryder

CS 428 Computer Networks

12

Related Documents


More Documents from ""

Javascript
May 2020 19
Ch8 Structures
April 2020 24
Ch4 Functions
April 2020 24
Cold Fusion Ii
May 2020 21