Networking Networking ComputersComputers

Client-Server & Peer-to-Client-Server & Peer-to-Peer NetworksPeer Networks

Learning Objectives:Learning Objectives:

By the end of this topic you should be By the end of this topic you should be able to:able to:

describe describe client-serverclient-server and and peer-to-peer-to-peerpeer networks networks

give give advantages and disadvantagesadvantages and disadvantages of each type;of each type;

What is a network?What is a network?

What is a network?What is a network?

a group of a group of computers connected computers connected togethertogether in order to in order to shareshare resources resources

What is a network?What is a network?

a group of a group of computers connected computers connected togethertogether in order to in order to shareshare resources resources

a computer a computer not connectednot connected to any to any other is a other is a s****d-a***e computers****d-a***e computer

What is a network?What is a network?

a group of a group of computers connected computers connected togethertogether in order to in order to shareshare resources resources

a computer a computer not connectednot connected to any to any other is a other is a stand-alone computerstand-alone computer

Client-Server NetworkClient-Server Network

Client-Server NetworkClient-Server Network usually has a powerful, controlling usually has a powerful, controlling serverserver

computercomputer controls the printers, storage, security …controls the printers, storage, security …

client computers are connected to the client computers are connected to the server via a switchserver via a switch or other network communication deviceor other network communication device

can be a number of servers:can be a number of servers: file server, application server, mail server, proxy file server, application server, mail server, proxy

server, print server, back-up serverserver, print server, back-up server

Advantages of a Client-Server Advantages of a Client-Server NetworkNetwork

users can users can log on at any client computerlog on at any client computer data files, printers, software available anywheredata files, printers, software available anywhere

network operations can be handled centrally network operations can be handled centrally at the server:at the server: backup, software roll-out, software updates, anti-backup, software roll-out, software updates, anti-

virusvirus no need for user to be involvedno need for user to be involved

security handled centrallysecurity handled centrally in a structured mannerin a structured manner data securedata secure audit logs keptaudit logs kept

Disdvantages of a Client-Disdvantages of a Client-Server NetworkServer Network

costcost server computers are powerful & expensiveserver computers are powerful & expensive network hardware required (hubs, switches, network hardware required (hubs, switches,

routers …..)routers …..) technician support essential for maintenancetechnician support essential for maintenance

reliancereliance on server & network on server & network infrastructureinfrastructure if server fails then centrally held data availableif server fails then centrally held data available

speedspeed of operation of operation more users = slower access to resourcesmore users = slower access to resources

Peer-to-Peer NetworkPeer-to-Peer Network

Peer-to-Peer NetworkPeer-to-Peer Network all computers have all computers have equal statusequal status

no computer has a server roleno computer has a server role

each computer may have resources that each computer may have resources that others needothers need

linking home (or small business) linking home (or small business) computers togethercomputers together to share files or a printerto share files or a printer

online P2P networks existonline P2P networks exist Limewire/Bitorrent allow file sharingLimewire/Bitorrent allow file sharing

Advantages of a Peer-to-Peer Advantages of a Peer-to-Peer NetworkNetwork

no reliance on central serverno reliance on central server if computer fails others are not badly affectedif computer fails others are not badly affected

simple to set upsimple to set up useful for temporary, ad-hoc networkinguseful for temporary, ad-hoc networking little technical support required - lower costlittle technical support required - lower cost

network traffic is minimalnetwork traffic is minimal most resources provided by each computermost resources provided by each computer

Disadvantages of a Peer-to-Peer Disadvantages of a Peer-to-Peer NetworkNetwork

no centralised management of resourcesno centralised management of resources each user is responsible for their own backupeach user is responsible for their own backup anti-virus updates performed by each useranti-virus updates performed by each user

required software & data not available on required software & data not available on every computer every computer user has to use the same computer every timeuser has to use the same computer every time

security is ad-hocsecurity is ad-hoc sensitive files may be accessible to all userssensitive files may be accessible to all users required printer not availablerequired printer not available

Client-Server v Peer-to-Client-Server v Peer-to-PeerPeer