Technical paper | Client-server networks
Client-server networks
Please note: This document has been archived and is for your information only. This document was
originally published as an overview for the type of issues faced when schools were considering the
type of network most suited to their needs.
This advice has since been replaced by Becta’s Functional Specification, which is available here. The
Functional Specification is complemented by a Technical Specification which can be found in the
same location.
Contents
Introduction
What is a network and how will it solve my difficulties?
Types of network
What is a client-server network?
What are the main functions of client-server networks?
Thin client-server technology (TCST)
Does our school need a client-server network?
Introduction
Why should you consider whether you need a network? Connecting your school’s computers together
brings greater possibilities. Using a stand-alone computer, you may have been faced with one or more
of these difficulties:

Difficulties in teaching due to the set-up of each computer and inconsistency between the
software on one machine compared to the one next to it.

Keeping machines with confidential data stored on them separate from those for general use
with pupils.

Staff and pupils find practical difficulties, such as saving their information on a computer and
the same computer not being available to use in the following lesson.

Your school has only a few printers, which are connected to single computers in different
locations, and are not available when you need them most.

The school has a single telephone line. A computer is located near the telephone socket,
which provides sole access to e-mail and the Internet, and cannot facilitate the needs of all
users.
What is a network and how will it solve my difficulties?
A network system is made up of more than one computer connected together using cables, electronic
devices such as switches and routers, and printers. Connecting all of the devices together allows you
to share hardware and software resources. Networks evolved because there was a need to share
information and allow all users to make use of limited hardware like printers. It is more economical to
share one printer among several computers than to provide a printer for each one. As the information
that we store on computers in schools becomes more important to us, such as pupils’ examination
work, security becomes a higher priority. This is especially so when schools are connected to
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Becta | Client-server networks
computers outside the school, when internal data can be at risk. A network can provide solutions to
these problems.
Types of network
There are many different types and sizes of networks in existence today. A peer-to-peer network is a
small number of computers connected together, usually by a cable, which can be set up to allow
shared access to files or hardware on other computers in the network. This type of network is
relatively easy and economical to install. However, management, performance and security issues are
the biggest concerns. Without any software which enables you to access files easily wherever they are
stored, it can become very difficult to ascertain where the shared folders/files are, as well specifying
who has access to the shared resources. This searching for files can produce extra demand on
computers that may not be able to process requests quickly from so many users, thus increasing the
amount of time it takes to access and store information.
The other type of network, which is the main theme of this document, is a client-server environment.
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Becta | Client-server networks
What is a client-server network?
A client-server network is essentially a connected set of computers like a peer-to-peer network but it
has a ‘master’ computer called the server, which uses software called a ‘network operating system’ to
control what happens on the network. The computers that you use on the network are called ‘clients’
because they are ‘served’ by the server, for example, the client may ask to load a piece of software,
the server would find it and send it to the client along the network cable. The diagram below shows a
typical layout of all the pieces of hardware that are involved in a client-server network.
Figure 1
Client-server networks, therefore, have two basic components: a client and a server. A client is a
computer that uses the network to connect to the server and get data to view or edit. A client typically
requests a service to be performed. A service might be to run an application, e.g. word-processing
software, query a database, or save data. Whatever the request may be, the server is the resource
that processes the client service.
A server is a powerful computer that has a high capacity disk (or disks) used for storage and a backup tape system to ensure data is not lost. This type of system is designed to store and manage
resources for users. Depending on the configuration (set-up) of the server, it is possible to undertake
some of the processing work either on the client computers or centralised on the server.
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Becta | Client-server networks
Figure 2
The type of network in Figure 2 can be found in most secondary schools and other large educational
establishments, although primary schools are now realising the significance and benefits of such a
system. Depending on the specification and the number of services running on it, a single server can
support up to 100 client machines.
For you to use your server, you will need to install a network operating system (NOS). The most
common types of system in use are Microsoft Windows 2000/2003 Server although there are also
Open Source Linux solutions available. The NOS keeps a central database on the server of users’
details and their access passwords, controlling which facilities they can use on the network. For
example, some users may be restricted to using only certain pieces of software, while other users may
need access to folders on the network containing files solely for their own department or subject use.
Each user has a login name and password. Users have access rights which are set up to define which
resources they may access. Access rights are based on their login name. Most schools will require
client computers to be monitored centrally and new software distributed from the file server, which
makes software upgrades and troubleshooting much easier. The database can be set up to back up
automatically to a tape drive as a security measure.
A client-server network does require someone with considerable expertise to operate and manage it
on a regular basis. In some schools, you may find specialist systems software that includes
administrative tools developed by suppliers, such as Research Machines (RM) and Viglen (whose
tools are called Connect and Classlink respectively). Please note that these are software tools and not
the actual network operating system. Connect and Classlink software have been designed to help a
school network administrator handle tasks such as:
 file and hardware sharing
 network management
 security
 remote access
© Becta 2004
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Becta | Client-server networks



disaster recovery
installing software applications
web caching (storing web content on the school’s server(s).)
These aspects are the main functional elements of client-server networks and are explained in more
detail below.
What are the main functions of client-server networks?

File and hardware sharing
The server manages files, software, printers, and other shared hardware on behalf of all client
computers on the network. Since all client machines are connected to the server, any pupil or
staff member can access resources available to them at any time using any networked
computer. The server compresses the size of the client file or hardware request and then
prioritises it and places it in a queue. As a result, the amount of traffic on the network is
reduced and communication only flows between the client, server and the shared hardware
without interrupting communication with the rest of the client machines.
Setting up file and hardware sharing can be complex, therefore, it is important that a member
of your staff be trained in basic administration. Additionally, you will need your supplier or
technical support team to provide detailed configurations, steps and sequences for explaining
the purpose of, and illustrating how to perform, the following set of activities:
i)
ii)
iii)
iv)
v)
vi)
vii)
viii)

Managing disk quota
Setting file, directory and printer permissions
Checking files and directories
How to share a file, directory and printer
Setting up network printers
Setting up network printer sharing devices
Installing print drivers and setting the printer properties
How to install and remove network applications
Network management
As the number of computers on your network increases, greater organisation is required to
operate efficiently. Network management tools in the server’s network operating system help
to manage files, printers, software and user data at the server or remotely. The server is
configured so that each user has access to their own directory, along with public directories
where applications are stored. Shared directories allow schools to set up different groups or
the whole school to access common files and directories.
Providing access to the network, software upgrades and troubleshooting can be administered
on the server by one person and made available to all computers on the network. This will
allow administrators to work more productively and save time otherwise spent on maintaining
each client computer separately. It is possible for some of the maintenance work on the server
to be carried out remotely by your LEA or technical support team without visiting your school,
again saving time in school.
To ensure effective management of your client-server network, your supplier or technical
support team should provide detailed configurations, steps and sequences for explaining the
purpose of, and illustrating how to perform, the following set of activities:
i)
ii)
© Becta 2004
How to manage basic tasks such as user account modification, eg setting up new
users or deleting users from the system.
Ensuring understanding of which administrative tools will help implement and
maintain the school network in reduced time and administrative costs.
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Becta | Client-server networks
iii)
iv)
v)
vi)
vii)
viii)

Check if the supplier has customised tools for schools to perform user and
network management in some form of batch processing. This is useful when
schools need to create lots of user accounts and groups, or to modify/delete users
at the start and end of a school year.
How to manage domains and trust relationships (grouping of the computers).
How to replicate directories.
Adding and removing computers from your network.
Using DHCP manager (to set up the network structure).
Viewing and assigning IP addresses for setting up internet access.
Security
By centrally managing access to the network, the server can provide strict control over which
staff and pupils are allowed access to the sensitive data and shared resources that reside on
the network. A firewall system should be considered. This is a hardware and/or software
device that is placed between the internal network and external communication lines, eg an
ISDN line. Firewalls would ensure that hackers could not gain unauthorised access to the
school’s Local Area Network (LAN), particularly for areas of the school that may have wireless
networks, where security risks can be higher.
Your supplier or technical support team should provide detailed configurations, steps and
sequences for explaining the purpose of, and illustrating how to perform, the following set of
activities:
i)
ii)
iii)
iv)
v)
vi)
vii)
viii)

Logging on and logging off
Change log-on password
Locking and unlocking computer
How to manage security tools
Check security measures remain intact
Undertake periodic network and security analysis
Customising and manage desktop environment
Accessing the Internet safely
Remote access
Most servers have remote server programs that allow staff and pupils to connect to the school
network through a dial-up or a high-speed internet connection from outside the school. Once a
connection has been established, users can access data or programs on the network. Some
servers only allow access to its disk drives. Others allow you to access the server hard drives
and access to your computer on the network. Implementing this in school should not be
attempted without seeking further advice. There are obvious security issues around who and
what data should be accessed, for example, if a pupil dials in, what controls are there
regarding the viewing/using of the data?
Your supplier or technical support team should provide detailed configurations, steps and
sequences for explaining the purpose of, and illustrating how to perform, the following set of
activities:
i)
ii)
iii)
© Becta 2004
Connecting to the school network from home
Accessing the Internet – addressing authentication and authorisation
Managing and monitoring remote access connections - accounting
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Becta | Client-server networks

Disaster recovery (Service Continuity Management)
What would happen if an event, such as a server fault, created an inability to use your system
over a period of time? It is imperative that you are able to make the system operational in the
shortest possible time.
Your supplier or technical support team should provide detailed configurations, steps and
sequences for explaining the purpose of, and illustrating how to perform, the following set of
activities:
i)
ii)
iii)
iv)
v)
vi)
vii)
viii)
ix)

How to start up and shut down servers
Understand administrative alerts
View and manage event logs
Check server capacity and performance
Back up files to tape
Run virus scanning tools and install updates
Apply updates to known software problems in earlier systems and applications
software
Restore files from back-up media
Prepare and apply emergency repair disk
Client-server applications
Some application software is designed specifically for client-server networks. Internet access,
e-mail, anti-virus software and database connectivity run most efficiently on servers.
You should contact your supplier to determine which applications are appropriate for your
school.

Web caching
Initiatives in the UK education sector such as Curriculum Online require improved access to
internet resources. To maximise this and allow outbound internet access for users, web
information can be stored locally on your server (caching), which will save time by
downloading the content from the Internet once only. The web pages can then be accessed
relatively quickly directly from the server. It is possible to purchase and set up a server solely
for web caching.
Your supplier or technical support team should provide detailed configurations, steps and
sequences for explaining the purpose of, and illustrating how to perform, the following set of
activities
i)
ii)
How to set up a local cache server
Making all your web browsers use the cache
For more information on web caching and edge caches please refer to Becta’s technical paper
on caching systems. This can be downloaded from http://getconnected.ngfl.gov.uk
Thin client-server technology (TCST)
This type of client-server network adopts a structure similar to that of the mainframe system. It is not in
common use in schools, but some schools are piloting such an option.
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Becta | Client-server networks
In a thin client-server system, all the client machines are compact in design, with no hard disks, floppy
drives or CD-ROMs. The concept of this system is that it has the ability to display remote applications
and data that run on the server and not on the client.
You may be thinking that your network does this already. In a school environment, the software may
also reside on the server, however, this is either distributed or published to the user. The desktop
computer has a part to play in processing the system and application files. Any client machine that
runs a program or part of the application is not a thin client. With the thin client technology, all of the
processing is managed by the server; only keystrokes and mouse clicks are transmitted and/or
received between the thin client (dumb terminals) and the server.
All of the major hardware is now located in a single location and the software is accessed by dumb
terminals. As a result, this makes management more central and secure, and the systems are less
likely to be misused by ambitious students.
The main benefit of using thin clients is the ease of maintenance. (With desktop machines, more
administrative effort is required when installing new software or to modify client-side configuration
options.) The computers used by the staff and pupils are also much cheaper to purchase.
Figure 3
You are recommended to take further advice before purchasing such a system. Issues of compatibility
with existing systems and the provision of support will need to be addressed.
Does our school need a client-server network?
There are many issues that need to be considered. Purchasing, installing, configuring and operating a
network costs money. Besides the initial expense of hardware, software, and set-up time, the network
must be managed on a regular basis. Installing a client-server network will increase the demand and
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Becta | Client-server networks
need for technical support and network administration. Not all schools have the staff available to
provide these services and so these costs need to be drafted into the total cost of ownership. These
costs are derived from many factors:






How many users will your school have?
Will the users be spread over a number of classrooms, located in an ICT suite or in different
sites?
What type of information will the network need to carry?
What uses does the school need to support?
What type of internet access will support the school?
Who will manage the system?
Care is needed to prevent the spending of a substantial amount of money on technology without
sufficient knowledge to make informed decisions. Seek advice from your educational support service
and use the information available from Becta before purchasing.
Note: Please refer to the Glossary for a detailed definition of some of the terms contained in
this document.
© Becta 2004
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Last reviewed December 2004 - Archived June 2005
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