networking fundamentals and the internet

8/22/2019 Networking Fundamentals and the Internet

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Chapter 16

Networking Fundamentals

and the Internet


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You Will Learn

About the typical hardware componentsof a network

How several popular networkarchitectures manage data traffic

How data is transmitted over several

interconnected networks How communications layers and their

protocols are used on a network

continued


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You Will Learn

About many of the popular applications

used on a network

How to connect to a network using amodem and a phone line

About the Internet and how to support

PCs connected to the Internet


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An Overview of Networking

A means of connecting computers togetherso they can share data (files and programs)and resources (printers and modems)

Network hardware and network software

Terminology Node

Packet or frame Header

Trailer


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The OSI Layer Network Model

A seven-layer model of communications

supported by a network; layers are

responsible for: Disassembling data into segments to be assigned

to separate packets

Later reassembling packets into contiguous data

Passing packets to and receiving packets from thenetwork media or cabling

Refers to software and firmware only


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Seven Layers of the OSI Model

Application layer Interfaces with the user or application using the

network

Presentation layer Compresses and decompresses data and

interfaces with the application layer and thesession layer

Session layer Makes and manages a connection between two

nodes of the network

continued


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Seven Layers of the OSI Model

Transport layer Verifies data and requests a resend when the data

is corrupted

Network layer Routs packets

Data-link layer

Disassembles packets and reassembles data intopackets

Physical layer Interfaces with the network media (cabling)


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Data Frames


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Network Architectures

Most popular physical network architectures

Ethernet

Token Ring Fiber Distributed Data Interface (FDDI)

Relatively new type of network

Asynchronous Transfer Mode (ATM)

Very fast

Works well over both short and long distances


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Networks

Basic differentiating characteristics

How computers are logically connected

How traffic is controlled

Network types

LAN

WAN

Internetwork


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Ethernet

Most popular network topology

Configured as either a bus or a star

A passive network (the computers, notdedicated network devices, drive thesignals over the network)

Contention-based system (eachcomputer contends for the opportunityto transmit on the network)


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Ethernet


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Ethernet

Uses Carrier Sense Multiple Access with

Collision Detection (CSMA/CD)

Carrier sense Computer must sense that network is free to handle its

transmission before initiating a signal

Multiple access

Many computers use the same network

Collision detection

Each computer must detect and manage collisions


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Ethernet Cabling Systems

Can use any one of six cabling systems

Two most popular

10BaseT

10Base2 (Thinnet)


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10BaseT Networks


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Thinnet Networks


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Token Ring

Physical star but a logical ring

Stations are connected to a centralized

multistation access unit (MAU) in a star formation Compared with Ethernet:

More robust and reliable

More complex and expensive

More difficult to maintain

Can use UTP or STP cables that have 2

twisted pairs for a total of 4 wires in the cable


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Connecting Components on a

Token Ring


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Communication on a Token

Ring

Controlled by a token

A small frame that constantly travels

around the ring in only one direction When a station seizes the token, it controls

the channel until its message is sent


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FDDI

Does not require a centralized hub,

making it both a logical and physical

ring Often used as a backbone network

(links several networks together)

Often uses fiber-optic cabling


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FDDI


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FDDI


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Summary of Network

Architecture


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Networking Hardware

Some common components

Network interface card (NIC)

Provides a PC with direct connection to network

Hubs

Provide centralized location for nodes to

connect on a star network

Bridges, routers, and gateways

Connect one network to another


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Network Interface Card (NIC)

A network adapter board that plugs into

a computers system board and

provides a port on the back of the cardto connect a PC to a network

Requires an IRQ, an I/O address, and,

for DOS and Windows 9x real mode,upper memory addresses


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Network Card Communication


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Combo Card


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Considerations when Selecting a

Network Card

Type of network you are attaching to(e.g., Ethernet, Token Ring, FDDI, or a

proprietary network standard) Type of media you are using (e.g.,

shielded twisted-pair, coaxial, or fiber-optic cable)

Type of I/O bus you are attaching thecard to (e.g., PCI or ISA)


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Bridges, Routers, and Gateways

Devices used to connect networks and

network segments to each other

Main reasons for internetworking Extend geographical area past what a

single LAN can support

Decrease traffic on a single LAN bydividing the LAN into more than one

network


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Bridges, Routers, and Gateways

Bridge Hardware device, coupled with software at the

data-link layer, used to connect similar networks

and network segments

Router Transfers a packet to other networks only when

the packet is addressed to a station outside its

network Gateway

Device or process that connects networks withdifferent protocols


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Networking Software Overview

Each layer in the OSI model uses a different

protocol

Firmware on network cards controls the twolowest layers (physical and data-link)

OS managing the network controls most layers

Best known: UNIX, NetWare by Novell, and Microsoft

Windows NT

Third-party add-on software can provide top layers

Examples: Netscape Communicator, Chameleon by

NetManage, and Eudora by QUALCOMM


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Networking Software Overview


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Network Protocol

Point-to-Point Protocol (PPP)

A common way PCs with modems can

connect to an internet TCP/IP

Supports the internet

IPX/SPX protocol Used by Novell NetWare for LANs


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Network Protocol

NetBEUI protocol

Proprietary Microsoft networking protocol

used only by Windows-based systems, andlimited to LANs because it does notsupport routing

Protocols to communicate with their

counterpart services on the receivingnode of the network

Examples: SMTP, HTTP, FTP


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Network Services

Web browsers

Chat rooms

E-mail

FTP

Telnet

Print services

Network drive


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Two Network Configurations

Peer-to-peer network

Users at each workstation can use shared printers

and files on each others computers

Services are often limited to FTP, print services,

and network drives

Dedicated-server network

Has at least one computer, or server, on thenetwork that serves the other computers on the

network


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Peer-to-Peer Network


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Dedicated-Server Network


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Networking with Windows 9x

and Windows NT Workstation

Methods of connecting to network

Network card (Ethernet, Token Ring, or

other design) Direct cable connect (serial or parallel port)

Dial-up networking (modem and phonelines)

Installing a network card Supporting PCs on a network


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Dial-Up Networking (DUN)

Allows a PC to remotely connect to a

network through a phone line

Uses PPP to send packets of data overphone lines


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How DUN Works


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Creating a Dial-Up Connection


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Dial-Up Adapter


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Direct Cable Connection


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Installing Network Adapters Using

Windows 9x and Windows NT

Installing an NIC under Windows NT

Installing an NIC under Windows 9x

Using resources on a network

i C


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Installing an NIC under

Windows NT

I lli NIC d


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Windows NT

I lli NIC d


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Windows 9x


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Using Resources on a Network


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Servicing PCs on a Network

Verify that the PC is network-ready

Log off the network

Save network files and parameters to disk Disconnect network cable and repair the PC

Restore network configurations

Reconnect PC to the network Verify that network resources are available to

the PC


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Saving Network Files and Parameters

to Disk Using DOS or Windows 95


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PCs and the Internet

Internet

The worldwide collection of over a million

hosts that can communicate with eachother using TCP/IP

A web of interconnecting, yet independent,

networks


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How the Internet Works


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Connecting to the Internet

Most people use an Internet service

provider (ISP)

Provides access to the Internet for amonthly fee

Provides online services


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IP Addresses

Internet Protocol (IP) address

A 32-bit dotted-decimal addressconsisting of four numbers separated byperiods

Used to uniquely identify a device on anetwork that uses TCP/IP protocols

Divided into three classes based onnumber of possible IP addresses ineach network within each class


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Classes of IP Addresses


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Reserved IP Addresses

Static and D namic IP


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Static and Dynamic IP

Addresses

Static IP address

Permanently assigned to a workstation

Dynamic IP address An assigned IP address used for current

session only

When session is terminated, IP address isreturned to the list of available addresses


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Domain Names

Unique, text-based name that identifies

an Internet address

Typical endings in the United States:.edu, .gov, .com, .org, .net

Also include a country code


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Domain Name Resolution

Services that track relationships

between domain names and IP

addresses Domain Name System or Domain Name

Service (DNS)

Windows Internet Naming Service (WINS)

The Internet Networks and


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The Internet, Networks, and

Subnets

The many different protocols that make

up the TCP/IP protocol suite

How TCP/IP uses the IP addresssystem


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Routing Using TCP/IP

TCP/IP uses routers to transfer packets

of data (datagrams) from network to

network in such a way that the overalltransmission makes all these networks

appear to be one large network

Each protocol of the CCP/IP suiteperforms a single task


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The Suite of TCP/IP Protocols

IP Addresses and Physical


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IP Addresses and Physical

Addresses


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How TCP/IP Routing Works

Default Gateways and Network


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Default Gateways and Network

Masks


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Subnets and Subnet Masks

Subnet

Division of a large network, consisting of

smaller separate networks, each assigneda logical network IP name

Subnet mask

Defines which portion of the host addresswithin an IP address is being borrowed to

define separate subnets within a network


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Classless Addresses

Class C network addresses that a

service provider owns and then

subleases to small companies


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Classless Addresses


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Routing Packets over Networks

Static routing

Routing tables dont automatically change

and must be manually edited Dynamic routing

Routing tables are automatically updated

as new information about routes becomes

known and is shared by one router with

another

Configuring TCP/IP with


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Windows 9x



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Windows 9x



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Windows 9x



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Windows NT



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Windows NT

Establishing Dial-up Connection to


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Establishing Dial-up Connection to

the Internet Using Windows 9x

Install and configure the modem

Configure Dial-Up Adapter

Configure Dial-Up Networking

Install applications software to use the

Internet

Configuring Dial-Up


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Configuring Dial Up

Networking

Configuring Dial-Up


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Configuring Dial Up

Networking


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Examples of Network Services

Most function at top three layers of the

OSI model -- application, presentation,

and session layers Must be a program running on both

nodes of the network for the service to

work


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Upper-Level Protocols

Hypertext Transfer Protocol (HTTP)

Used by the World Wide Web

File Transfer Protocol (FTP) Used to transfer files

Simple Mail Transfer Protocol (SMTP)

Used to transfer e-mail

Uniform Resource Locator


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Uniform Resource Locator

(URL)


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World Wide Web Browsers

Provide interface between Web sites and PCs

Access a server by either its IP address or its

domain name

Use HTTP to request and pass documents on

the Web

Terminology

Hypertext

HTML

i f


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File Transfer

File Transfer Protocol (FTP)

Used to transfer files between two

computers using same or different OS Can be initiated at a command prompt

or using an ISP

File Transfer from a Command


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File Transfer from a Command

Prompt

Fil T f U i ISP


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File Transfer Using an ISP

Fil T f U i ISP


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File Transfer Using an ISP

N t k D i M


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Network Drive Map

One of most powerful and versatile methods

of communicating over a network

Uses network file service (NFS) software to

make one PC appear to have a new hard

drive

Files and folders on host computer are

available even to network-unaware DOSapplications

Preparing a Windows NT Host


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Computer for a Network Drive Map



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Mapping the Network Drive from a


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pp g

Remote to a Host Computer



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pp g




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pp g


Network Troubleshooting


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g

Guidelines

Windows 9x dial-up problems (modemproblems) Cannot make a connection

You can connect, but you get the messageUnable to resolve hostname

After connecting, you get the error messageUnable to establish a compatible set of networkprotocols

Problems with TCP/IP Problems with TCP/IP configuration or suspected

network problems (packet Internet groper orPING)

Ch t S


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Chapter Summary

Fundamentals of the hardware and

software that make up networks

How to support a PC that interfaces withthe Internet

networking fundamentals and the internet

Documents