Client-Server and Peer-to-Peer Networks

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Client-Server Network

A server provides all of the services required on the network. These services include directing traffic around the network, managing disk drives and network peripherals such as printers and scanners.

The 'clients' are people who use workstations in order to access the network and its features.

Client-Server networks are often used for middle to large organisations. In larger set-ups there may be several servers on the network, each one dedicated to a task or service.

For instance:

A print server which handles all of the print jobs required by network users

An email server which provides a centralised email service for all network users

File servers to provide extra storage capacity

An authentication server which handles all log-in and security measures

A web server to provide an internal intranet service

Client-Server Properties

All data and applications held centrally

Data Backups

One large back up can be performed on the server rather than manually backing up each client computer.

Backing up each computer individually would take up lots of time and bandwidth.

Anti Virus Scans

Anti-virus schedules can be set by the server, this takes the processing burden away from the client computers.

Maintaining the anti-virus software on the server allows for updates to be installed easier, keeping the computers and server secure.

Security

Improved as the data is held on a secure server in a data room rather than an open office.

Improved as each log-in is authenticated by a username password

Improved access to the Internet as it is being controlled through the the server. Proper Firewall and data policies can be managed.

Licenses

​​​​​​​Software licenses can be controlled, ensuring the organisation is within its license quota for each application.

Access Rights

Access rights or levels can be easily assigned through the use of a server.

For example, teachers at a school could view student information, whereas school cleaners cannot.

Storage Limits

Storage quotas can be set for each user or department. Thus making the most efficient use of server hard disk storage space.

User Roaming

People can log in to any client computer and their desktop, applications and data will be available as it is all stored on a remote server.

Shared Peripheral Resources

Time efficiency

Saves the client from waiting to use a peripheral as jobs can be queued through the network.

Improved performance and cost savings

Performance is also improved as purchasing a single high speed laser printer is cheaper than buying several slower printers attached to each client.

By sharing this resource the investment is worthwhile.

Improved Reliability

Having a single managed print service is better than having to maintain a whole collection of individual printers

Client-Server Issues

Number of People

A Client-Server network is complex to set up. So it is a bit of an overkill if there are only two or three people using the system.

Expertise Required

Setting up the server is a complex technical task as well as maintaining ans sorting out technical problems as they arise. So it tends to need a network manager to handle this.

A network manager is costly.

Servers are expensive

Servers are designed to be robust, reliable and high performance, which is expensive.

The operating system is also more costly than the standard stand-alone types as it has to deal with a networked environment.

Server down

If the server has a problem or the network connection fails then no one can do any work.

This is why servers are designed to be reliable.

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Peer-Peer Network

In a 'peer-peer' configuration there is no central server. Each workstation is loaded with the appropriate applications needed for that machine and local resources such as an attached printer folder or external hard drive can be shared.

The peer-peer network form is most commonly found in the home or a small office.

In the set-up above the Modem / Router is providing internet access. It may be set up to issue an IP address for each machine, this is called a DHCP host or 'Dynamic Host Configuration Protocol'. If a new computer is plugged into the network, it requests an IP address from the router.

Peer-Peer Characteristics

Peer-peer is popular because it is simple to set up.

Other computers can be attached directly to the network using a network cable or wireless connection.

Cheaper when compared to a client-server set up. No server costs and no high technical expertise to maintain it.

Each is set up to share folders and peripherals such as printer, scanner, external hard drive.

Disadvantages

The main issue is that every machine is effectively independent.

Each one needs the correct applications loaded.

Your data is held on a specific machine which must be powered up. Although setting up a 'share' will allow you to see this on the other machines as well.

Each one needs its own anti-virus scanner

Each one needs its own backup schedule - either by backing up to a networked hard drive or to its own external storage device.

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Client-Server vs Peer-Peer

Set up

CS: Complex to set up

PP: Simple to set up

Maintenance

CS: Requires technical expertise to set up and maintain

PP: Needs basic technical skills

Server

CS: Server present

PP: No server present, each computer is a 'peer' of the others

Data

CS: Centralised data and application management

PP: Each computer has its own data and applications loaded

Operating System

CS: Uses a dedicated network operating system

PP: Uses standard operating system with network capabilities

Security

CS: Security is managed centrally and the server can be in a locked room

PP: Only as secure as the most vulnerable computer in the network e.g. a wireless laptop is not physically secure

Authentication

CS: User access and authentication is managed centrally

PP: Fairly basic login authentication for each user

Peripheral

CS: Peripherals are managed centrally and available to client computers

PP: Peripherals can be shared but the computer that it is attached to must be powered on as well

Accessibility

CS: Users can roam from machine to machine and still have access to their applications, data and desktop setup

PP: User data is only stored on a specific machine. User data must be in a 'share' folder if it is to be visible on the other machines