An Introduction to Networking

Chapter 1

You will:

• List the advantages of networked computing relative to standalone.

• Distinguish between client/server and peer-to-peer networks.

• List elements common to all client/server networks.

• Describe several specific uses for a network.

• Identify some of the certifications available.

• Identify the kinds of skills and specialization that will help.

Topics

Networking Terminology

Network Topologies

Network Building Blocks

Standard Network Models

Network Categories

Two basic types of Networks

• LAN

A WAN

– A network that spans multiple geographic locations.

Network Definitions

• ServerServer:– A networked device that shares its resources with other

devices.

• ClientClient:– A personal computer or workstation in that requests

services from a server

• PeerPeer:– A self-sufficient computer that acts as both a server and a

client

• Host:Host:– Main frame type device that does all the processing

• Terminal:Terminal:– Usually dumb consists of a keyboard and a low-grade

video display and does not do processing.

Networks

• Definition:– A group of computers that are

connected together to communicate and share resources such as files, printers, and email.

S

Servers

General purposeGeneral purpose DedicatedDedicated

Server Server

• Definition:– A network computer that shares

resources with and responds to requests from other network computers, including other servers.

Types of Servers

• File Server• Print Server• Proxy Server• Application Server• Web Server• Mail Server• Fax Server• Remote Access Server• Telephony Server

Host Computers

• Definition:– A powerful, centralized computer system,

such as a mainframe computer, that performs data storage and processing tasks on behalf

of clients and other network devices.

Processing and storageProcessing and storage

Network devices

Host Computers

• The term host can also refer to a workstation and server and is most commonly used when discussing TCP/IP-related services and functions.

• A host, in TCP/IP terms, is any network device that has an IP address. – Workstations,– servers, and – any other network device (as long

as it has one or more IP addresses).

Peer-to-Peer Network

• Definition:– A self-sufficient computer that acts as

both a server and a client to other similar computers on the network.

Peer

Client and serverClient and server

Client and serverClient and serverClient and serverClient and server

Peer-to-Peer Network

Resources

Processing

Communication

Resources

Processing

Communication

Resources

Processing

Communication

Client/Server Network

• Definition:– A network computer that utilizes the

resources of other network computers

including other clients.Client 2Client 1

Processor, memory, storage

Processor, memory, storage

Terminals

• Definition:– A specialized network device on a host-

based network that transmits the data entered by the user to the host for processing and displays the results.

Terminal

No processorand no memoryNo processor

and no memory

Client

Authentication

• Definition:– A network security measure in which a

computer user or some other network component proves its identity in order to gain access to network resources.

Who I amWho I am

How do I know?How do I know?

User name & passwordUser name & password

ApprovedApproved

Encryption

• Definition:– A network security measure in which

information is encoded or scrambled prior to transmission so that it cannot be read unless the recipient knows the decoding mechanism, or key.

Ox12jOx12j DataData

Encrypted data

Client Server

Decrypted data

Network Directories

• Definition:– A centralized database that includes

objects such as servers, clients, computers, user names, and passwords.

Centralizedadministration

Centralizedadministration

AuthenticationAuthentication

Network Topologies

• Physical Topology– Bus– Star– Ring– Mesh

• Logical Topology

A Physical Bus Topology

Terminator TerminatorT-connector T-connectorT-connector

A Physical Star Topology

Hub

Node

A Physical Ring Topology

A Physical Mesh Topology

A Hybrid Topology

A Logical Bus Topology

Sender Receiver

ReceiverReceiver

A Logical Ring Topology

A Logical Star Topology

Polls nodes and controls accessPolls nodes and controls access

Network Topologies

• Includes:– Nodes– Backbone– Segments– Subnets

Nodes

• Definition:– Any network device that can connect to

the network and can generate, process, or transfer network data.

Backbones and Segments

• A Backbone is the part of the network to which all segments and servers connect.

Backbones

• Definition:– The highest-speed transmission path

that carries the majority of the network data. Backbone

Segments

• Any discrete physical subdivision of a network.

SegmentSegment

Subnets

• A portion of a network that shares a common network address.

VLAN

Standard Network Models

• Centralized Computing Network

• Client/Server Network• Peer-to-Peer Network• Mixed Mode Networks

Centralized Computing Network

CommunicationCommunication

ProcessingProcessing

StorageStorage

Host

UserUser

Client/Server Network

Processing powerProcessing power

Management servicesManagement services

Administrative functionsAdministrative functionsServer

Client 2Client 1

Mixed Mode Networks

Host

Server Peer/Client

Peer/Client

Network Topologies

PhysicalPhysical

LogicalLogical

The Internet

An Intranet

Employee handbook

An Extranet

Company A

Company B

Company C

An Enterprise Network

InternetWANLAN

Network technologies LANWAN

Organization

Network Media and Hardware

• Bounded Network Media• Unbounded Network Media• Noise Control• Network Connectivity Devices

Terms to Know

• Signals:– Electromagnetic communications

you want to be transmitted across a network medium

• Noise:– Electromagnetic interference that

disrupts the signal.• Attenuation:

– Degradation of a signal as it travels across a network medium, usually caused by the accumulation of noise or fading strength of the signal.

Media Types

Bounded mediaBounded media

Unbounded mediaUnbounded media

Physical Media

• Three types of cable– Coaxial Cable– Twisted-Pair Cable– Fiber-Optic Cable

Coaxial Cable

Braided shieldingBraided shielding

Single copper conductor

Single copper conductor

Non-conductiveinsulated coating Non-conductive

insulated coating

• Male BNC

• Barrel

• T-Connector

• Terminator

Uses BNC connectors

F-Type Connectors

• The F-Type connector is a threaded, screw-on connector that differs from the BNC connector of early Ethernet mainly in its method of device attachment.

Twisted Pair Cable

Conductors are stripedConductors are striped

Pair has basecolor schemePair has basecolor scheme

Primary and secondary wirePrimary and secondary wire

UTP vs. STP Cable

Cable Type Description

UTP

Does not include shielding around its conductors. Typically contains four pairs of stranded or solid conductors. Inexpensive and reliable. Supports distances of up to 100 meters (328 feet). Supports data transfer rates up to 1 Gbps. 

STP 

Includes shielding, typically a foil wrapper, around its conductors to improve the cable's resistance to interference and noise. Typically contains four pairs of stranded or solid conductors. Supports distances up to 100 meters (328 feet). More expensive than UTP. Most commonly used in Token Ring networking. 

Twisted Pair Cable Categories

Category Network Type Maximum Speed

1Voice grade; not suitable for networking 

n/a 

2Digital telephone and low speed networks 

4 Mbps 

3 Ethernet   10 Mbps 

4 IBM Token Ring   16 Mbps 

55e

Fast EthernetGigabit Ethernet 

100 Mbps350 Mbps 

6 Gigabit Ethernet  1 Gbps 

7 Gigabit Ethernet  1 Gbps+ 

An RJ-45 Connector

1 W/Green2 Green3 W/Orange4 Blue5 W/Blue6 Orange7 W/Brown8 Brown

P3

P1 P2

P4

Pin and Wire Colors

RJ-45 with locking tab facing away

Pin 1 Pin 8

Connector Pin - Out

EIA/TIA COLOR SCHEME 568 A 568B

1- Tx (+) 1- WHT/Green 1-WHT/Orange

2- Tx (-) 2- Green 2- Orange

3- Rx (+) 3- WTH/Orange 3- WHT/Green

4- 4- Blue 4- Blue

5- 5- WHT/Blue 5- WHT/Blue

6- Rx (-) 6- Orange

6- Green

7- 7- WHT/ Brown 7- WHT/Brown

8- 8- Brown 8- Brown

Exercise

• Making a Patch cable or Cross-over Cable.

http://www.rmfred.com/Wiring%20Guide/Wiring%20Guide.htm

Ethernet Cable Descriptions

• 100Base-TX• 1000Base-TX• 1000Base-SX• 1000Base-LX• 1000Base-CX• 10GBase-SR• 10GBase-LR• 10GBase-ER

Comparing Media

TechnologyTechnologyTransmissionTransmission

Distance Distance BandwidthBandwidthInstallationInstallation

EaseEaseConnectorConnector

TypeType

ThinNet 185 meters (600 feet) 10 Mbps Easy BNC

ThickNet 500 meters (1640 feet) 10 Mbps Difficult—Stiff cable Vampire taps

UTP 100 meters (320 feet) 10 Mbps to Gigabit Easy RJ-45

STP 90 meters (288 feet) 10 Mbps to Gigabit Difficult Specialized

Single-mode fiber Kilometers Gigabit and beyond Very difficult Specialized

Multimode fiber 2500 meters Gigabit Difficult SC and ST

Broadcast radio Up to 40 Kilometers 10 Mbps and up Easy

Infrared Short distances 10 Mbps and up Easy

Microwave Kilometers 10 Mbps and up Difficult

IEEE 1394 (FireWire)

• FireWire runs at 100, 200, 400Mbps (800Mbps in the 1394b standard), but in its standard mode it has a cable length limitation of 15 feet (4.5 meters),

A Fiber Optic Cable

Inner jacketInner jacket

Silica claddingSilica claddingOuter jacketOuter jacket

Glass or plastic coreGlass or plastic core

Fiber Optic Cable Mode Types

• Single-mode fiber• Step index multimode fiber• Graded index multimode fiber

Fiber Optic Connectors

ST SC FC

SMA

FDDI Mini-BNC Biconic

MT-RJLC

FireWire Connectors

Four-pinFour-pin Six-pinSix-pin

Plenum and PVC Cable

Unbounded Network Media

• Wireless communication• Radio Networking• Infrared Transmission• Microwave Transmission

• Signals transmitted as electromagnetic energy

• Enables users to move around • Can be point-to-point• Permits connections in areas

where it would be difficult to install wires

Wireless Communications

• Nondirectional; uses a single frequency for transmissions• Comes in low- and high-power versions • Low-power RF transmissions travel a short distance

– Inexpensive and relatively easy to install

• High-power RF transmissions travel considerably farther– Specially-trained technicians are often required to install

– More expensive type of system

Radio Networking

Infrared Transmission

Receiver

• Requires line of site

Satelite Transmission

Sender transmits electromagnetic signals

Sender transmits electromagnetic signals

Receiver has unobstructed view

Receiver has unobstructed view

• Requires line of site

Microwave Transmission

• Requires line of site

• Affects both bounded and unbounded network transmission.

• Unwanted signals that are introduced into network media.

Electrical Noise

Shielding

Secondary buffer to 900 µmSecondary buffer to 900 µm

Glass coreGlass corePrimary bufferPrimary buffer

Noise

Drain

Glass claddingGlass cladding

Differential Signaling

• Noise reduction technique in which the signals from two inputs are compared: signals that are identical on

the two inputs are ignored,

while those that are different on the inputs

are accepted

Noise Control with Twisted Pair

• Primary difference in cable categories is the number of twist per foot.

Termination

Terminator Terminator

Prevents signal reflection

Prevents signal reflection

– The bus must be terminated at both ends of the chain.

Grounding

Pipe connects to earth

Pipe connects to earth

Ground pointGround point ConductorConductor

Grounding

• Provides a means for noise to be drained off the line.

• Grounding refers to making a direct connection to the earth.

Media Installation Techniques

• Separate data and electric cables

• Fluorescent lights• Power ground• Connector installation

Network Interface Card Types

• Motherboard• USB • PC card• FireWire• Internal adapter card

A Transceiver on a Cable Modem Card

Transceiver chipTransceiver chip

A Transceiver on a Modem Card

Transceiver chipTransceiver chip

Premise Wiring

Rack in a wiring closetRack in a wiring closet

Patch cablePatch cable

Patch cablesPatch cables

Patch panelsPatch panels

A Repeater

Repeater

– A device that regenerates a signal to improve transmission distance.

A Hub

Hub

A Switch

Switch

Connects pairs of ports

Connects pairs of ports

A Bridge

Bridge

Divides network based on MAC

addresses

Divides network based on MAC

addresses

A Dedicated Router

Router

Divides network based on network

addresses

Divides network based on network

addresses

A Wireless Access Point

WAP

A Gateway

Gateway

LAN mediaLAN media WAN mediaWAN media

Network Standards

• Definition:– A set of specifications,

guidelines, or characteristics applied to network components to ensure interoperability and consistency between them.

Network standards

Number of computers

Connector type

Cable length

Standards Organizations

• ISO• IEEE• ANSI• TIA/EIA• IETF

Video:

• Warriors of the Net