Chapter 1An Introduction to Networking

Collected and CompiledBy JD WillardMCSE, MCSA, Network+, Microsoft IT Academy AdministratorComputer Information Systems InstructorAlbany Technical College

Attention: Accessing Demos• This course presents many demos. • The Demos require that you be logged in to the Virtual

Technical College web site when you click on them to run. • To access and log in to the Virtual Technical College web site:

– To access the site type www.vtc.com in the url window– Log in using the username: CIS 1140 or ATCStudent1– Enter the password: student (case sensitive)

• If you should click on the demo link and you get an Access Denied it is because you have not logged in to vtc.com or you need to log out and log back in.

• If you should click on the demo link and you are taken to the VTC.com web site page you should do a search in the search box for the CompTIA Network+ (2009 Objectives) Course and run the video from within that page.

Objectives

• List the advantages of networked computing relative to standalone computing

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

• List elements common to all client/server networks

Why Use Networks?

• Network: group of computers and other devices that are connected by some type of transmission media

• Commonly connected devices include computers, laptops, mainframe computers, terminals, printers, fax machines, PDAs, cell phones, and various data storage devices

• Advantages of networks are that they actually save organizations money by allowing them to:– Centralize Administration– Consolidate (centralize) data storage – Share data and peripheral devices like printers – Increase internal and external communications – Increase productivity and collaboration

Networking Basics Demo

Types of Networks

• Models vary according to:– Computer positioning– Control levels over shared resources– Communication and resource sharing

schemes

• Network models– Peer-to-peer– Client/server

Network Models Demo

Peer-to-Peer Networks• Direct computer communication

– Equal authority• Individual resource sharing

– Users act as their own administrator• May share resources• May prevent access to resources

• Traditional model– Two or more general purpose computers:

• Capable of sending and receiving information to and from every other computer

• Environments– Small home or office– Large networks using the Internet

• Gnutella, Bitcoin, original Napster• BitTorrent software

Peer-to-Peer Networks (cont’d.)

• Resource sharing method– Modify file sharing

controls• User responsibility

• Lack centralized control • Access may not

be uniform or secure

Resource sharing on a simple peer-to-peer network

Peer-to-Peer Networks (cont’d.)• Advantages

– Simple configuration• Computers are in same general area• No dedicated server or hierarchy

– Less expensive• Compared to other network models

• Disadvantages– No centralized storage– Not flexible

• Difficult to expand (not scalable) – Not necessarily secure

• Decentralized security model– Security is maintained on each individual computer

– Not practical for large installations• Usually 10 or fewer workstations

Peer to Peer vs. Server Centric Demo

Client/Server Networks• Computer roles

– Server• Central computer• Facilitates communication and resource sharing between clients

– Clients• Personal computers• Also known as workstations• Run local applications• Store data locally• Use server shared applications, data, devices• Use server as intermediary

• Central resource sharing controlled by server– Centralized security model– Sharing data, storage space, devices– No direct sharing of client resources

• Communication– Switches or routers

Client/Server Networks (cont’d.)• Server requirement

– To function as a Server, a computer must be running a network operating system (NOS)

• Manages client data, resources• Ensures authorized user access• Controls user file access• Restricts user network access• Dictates computer communication rules• Supplies application to clients

• Server examples– UNIX, Linux, Microsoft Server 2008 R2, MAC OS X Server

• Server features relative to clients– More memory, processing, storage capacity– Equipped with special hardware

• Provides network management functions• Data Redundancy

Client/Server Networks (cont’d.)

Resource sharing on a client/server network

• Advantages relative to peer-to-peer networks

– User credentials can be assigned in one place

– Multiple shared resource access centrally granted to a single user or groups of users

– Centralized backup– Central problem monitoring,

diagnostics, correction capabilities from one location

– Servers are optimized to handle heavy processing loads and dedicated to handling requests from clients, enabling faster response time

– Because of their efficient processing and larger disk storage, servers can connect more than a handful of computers on a network

– More scalable• Supports many users

• Disadvantages relative to peer-to-peer network• Complex design and maintenance

• Requires extensive advanced planning• Server operating systems are expensive

Client Server and Peer-to-Peer Networks (2:47)

LANs, MANs, and WANs• LAN (local area network)

– Network confined to a relatively small space such as a building or an office

– 1980s

• LANs became popular as peer-to-peer based

– Today

• Larger and more complex client/server network

• High speed networks

• Typically Ethernet

– Star-wired networks using fiber optic cables, twisted-pair cables, and wireless

Interconnected LANs

LANs and WANs Demo

LANs, MANs, and WANs

• MAN (metropolitan area network)– Sometimes called a CAN (campus area network)

• Larger than a LAN• Generally covers campuses or office

complexes – Connects clients and servers from multiple

buildings– Uses different transmission media and

technology than LAN

LANs, MANs, and WANs (cont’d.)

• WAN (wide area network)– Connects two or more

geographically distinct LANs or MANs (states, countries, continents)

– Uses different transmission methods and media than LAN

• Communication circuits connected by routers

– Network connection• Separate offices in same

organization• Separate offices in

different organizations

A simple WAN

Elements Common to Client/Server Networks

• Client– Network computer requesting resources or services from

another network computer– Client workstation human user– Client software installed on workstation

• Server– Network computer managing shared resources– Runs network operating software that can manage not only

data, but also users, groups, security, and applications on the network

• Workstation– Personal computer

• May or may not be connected to network

Network Requirements Demo

Elements Common to Client/Server Networks (cont’d.)

• NIC (network interface card)

– Device inside computer

– Connects computer to network media

– Allows communication with other computers

• NOS (network operating system)

– Server software

– Enables server to manage data, users, groups, security, applications, and other networking functions

A NIC (network interface card)

Elements Common to Client/Server Networks (cont’d.)

• Host– Computer– Enables network resource sharing by other computers

(hosts resources)– Identified by unique network address

• Node– Client, server, or other device connected to a network

• Connectivity device– Allows multiple networks or multiple parts of one

network to connect and exchange data

Elements Common to Client/Server Networks (cont’d.)

• Segment– Group of nodes– Uses same

communications channel for traffic

• Backbone– Connects segments

and significant shared devices

– “A network of networks”

A LAN backbone

• Topology• Computer

network physical layout

• Ring, bus, star or hybrid formation

Common network topologies Demo

Network Topologies (4:52)

Elements Common to Client/Server Networks (cont’d.)

• Protocol– Standard method or format for communication

between networked devices• Packet

– Distinct data units exchanged between nodes• Addressing

– Scheme for assigning unique identifying number to every node on the network

Examples of network transmission media

• Transmission media • Means through

which data is transmitted and received

Summary

• A network is a group of computers and other devices that are connected by some type of transmission media

• In a peer-to-peer network, every computer can communicate directly with every other computer

• A client/server network uses a server to enable clients to share data, data storage space, and devices

• A LAN is confined to a relatively small space, such as a building or office

Summary

• A MAN is larger than a LAN and connects clients and servers from multiple buildings

• A WAN connects two or more geographically distinct LANs or MANs

• Elements common to client/server networks: client, server, workstation, NIC, NOS, host, node, connectivity device, segment, backbone, topology, protocol, data packets, addressing, and transmission media

The End