What is windows terminal server. Terminal access for small and medium enterprises

The introduction of terminal access tools has recently attracted considerable interest among the heads of many companies after all, this category of products, if properly applied, can provide a significant reduction in both the cost of maintaining a corporate software, and the cost of regular hardware updates. In this article, we will talk about what can give the use of this category of products to small companies.

What is terminal access

a long time ago, before personal computers were known to mankind, the typical architecture of any enterprise application was one that used a mainframe (or, in the case of a poorer company, a minicomputer) and a number of mainframe (or minicomputers) controlled by the same mainframe (or minicomputer) non-intelligent external terminal devices. Such an approach, based on the complete centralization of resources, data and applications, had certain advantages for all its shortcomings and the high cost of computer technology of those years, it, firstly, made it possible to solve problems that users of the first personal computers never dreamed of, and secondly , was distinguished by relative (naturally, for that time) ease of operation because all Computer Engineering physically located in one place, and users jointly operated common processor, memory, external devices, multitasking operating system and a set of applications.

Modern terminal access tools used on personal computers, specialized terminal workstations and handheld devices are based on a similar principle of centralization of computing and collectivization of resources. The user in this case runs on workstation client part of the terminal access tool and with its help accesses a remote server computer containing the corresponding server part this tool. Upon successful authentication, the server part of the terminal access tool creates its own session for the user, in which either the user manually or automatically (depending on the session settings and access rights) launches the applications he needs in the server address space. The user interface of applications launched in this way is available to the user of the workstation in the window of the client part of the terminal access tool, and he can control this application using the keyboard and mouse of the workstation information about the keys pressed and mouse movement (and often the contents of the clipboard) are transferred to the session this user on the server, and changes are sent back to user interface applications. When a user session ends, all applications running in it are closed.

Terminal access and IT infrastructure costs

The advantages of using terminal access become apparent when there are a large number of workstations or with increased requirements for security and centralization of data storage. If applications are accessed using a terminal access tool, then only the operating system and the client part of this tool will be installed on the workstations, while the applications themselves that users work with are installed on the terminal server. In this case, the costs of maintaining workstations are significantly lower than when they are fully equipped with client parts of corporate applications, office suites, mail clients and other products used in the company, and the requirements for the hardware of such workstations are very moderate. In addition, there are special workstations for Windows control CE, designed to work in this mode. True, the requirements for terminal server hardware can be quite high, depending on the number of concurrent users. But modern facilities terminal access, as a rule, are able to work with server clusters and perform load balancing.

While the savings in the cost of acquiring, upgrading, and maintaining workstations can be calculated fairly easily, the savings associated with providing additional security access to corporate data is not immediately obvious. Since the applications are running on a remote server, the end user workstation has neither the client part of the server DBMS used in the company, much less access to desktop DBMS files, and this significantly reduces the risk of unauthorized access to corporate data except by regular means (that is, using a corporate application) you will not be able to access them.

Leading Terminal Access Providers

Microsoft

The simplest terminal access tools, called terminal services, are part of the server Windows versions. Terminal Services is available for Windows NT Server 4.0, Terminal Server Edition (the first version of Terminal Access created in collaboration with Citrix), Windows 2000 Server, Windows 2000 Advanced Server, Windows 2000 Datacenter Server, Windows Server 2003 (all editions).

Terminal operating parameters management tools Windows Services relatively simple. At Windows application Server 2003, Enterprise Edition can balance server load; Maybe dynamic control session parameters; screen resolutions up to 1600X1200 and True Color mode are available to client sessions, and Windows Server 2003 Terminal Services clients can access their local resources ( external devices, disks, etc.) from within a terminal session. That, in fact, is all the capabilities of Windows Terminal Services available today. However, these services are often used by network administrators to manage servers remotely, and by software companies and departments to access applications installed on other computers.

Licensing of access through terminal services is carried out as follows. All devices that access Terminal Services must have a Windows Server 2003 Terminal Server Device License (CAL) that grants access to Windows Server 2003 for the device, or the user must have a Windows Server 2003 Terminal Server User CAL. In addition to this, there is Windows license Server 2003 Terminal Server External Connector License, which allows anonymous simultaneous connections to terminal services over the Internet and is intended for application providers.

Citrix

Citrix is ​​rightfully considered the market leader in terminal access today. This company produces terminal access tools for Windows and UNIX; at the same time, this set of tools differs from Windows terminal services (licensed at one time from the same Citrix) in a very wide range of options for setting up client sessions, as well as tools for managing terminal servers and other network resources involved in the use of terminal access, as well as a comprehensive set of integrated related tools and technologies, such as password management tools, secure access, roaming of terminal connections when moving a client from one place to another. Thus, using the tools included in the Citrix Access Suite running on top of Windows Terminal Services, you can set a very wide range of session parameters (window size, screen resolution, number of colors, rules for working with audio data), up to creating sessions that run in a windowed mode of only one specific application and ending at the end of its work, to carry out detailed monitoring of the entire distributed system and analyze the use of resources in user sessions, to implement optimal management of the so-called server farms server clusters containing applications of the same type, by balancing their load.

Note that when using Citrix technologies (in particular, the ICA Independent Computing Architecture), only information about mouse and keyboard input, as well as changes in the screen image, is transmitted over the network, which limits the bandwidth required for the session to less than 20 kbps.

Citrix Access Suite supports access to terminal servers from DOS, Windows, Mac OS, UNIX, Linux, OS/2, Java workstations from browsers using Netscape plug-ins or Active X controls for Internet Explorer, as well as from a wide range of mobile devices.

Accompanying Products

Starting to use terminal access, companies often face other challenges, such as managing access to applications, multiple user passwords, protecting transmitted data, providing access that does not depend on the infrastructure and type of device, user interaction among themselves and the effective maintenance of their IT services. service. For this purpose, they may need tools for managing passwords, organizing conferences, remotely managing workstations and their interface. All these products are available as part of the Citrix Access Suite, the release of which will allow us to talk about a fully integrated solution that provides a single infrastructure for user access to applications.

Terminal access for small businesses

It was traditionally believed that terminal access tools should be implemented in large enterprises with a large number of the same type of workstations, and reports on the most famous projects for the introduction of such tools often involve tens of thousands of jobs and huge budgets. However, there are products in this category that make sense to implement in small and medium-sized enterprises.

Of the novelties in this area, first of all, we note the Citrix Access Essentials product focused on this market segment. This product can serve companies using Microsoft platform Windows with no more than 75 terminal workstations (including portable and mobile devices), and meets the requirements of small companies, it will be relatively cheap to acquire and implement due to low-cost licenses (less than $ 250 for one workplace, which already includes a license to use Windows Terminal Services Windows Terminal Server Client Access License) and ease of deployment and administration.

Technical features of Citrix Access Essentials

Citrix Access Essentials is a server application that runs on Windows Server 2003 and provides access to applications installed on that server through a Web interface. This product requires one server with an operating system Microsoft Windows Server 2003 Standard or Enterprise Edition, network connection between users' devices and the server, and a Web browser on each connected device.

Citrix Access Essentials supports two operating modes: single server operation (Figure 1) and operation using the Citrix Access Gateway hardware (Figure 2). In the first case, remote users can access the terminal server through a firewall, in the second through the Access Gateway VPN virtual private network server (in this case, the terminal server is installed in the increased security application access).

To secure access to the server, Citrix Access Essentials supports several methods of user authentication, including the use of encryption.

Deploying the Citrix Access Essentials server is as simple as possible - for this purpose, the Quick Start utility is included in the product package, which is a wizard for installing and configuring the server, registering licenses, generating distribution kits for client parts, and publishing applications on the server. The client parts are available for all versions of Windows, Windows CE, Pocket PC 2003, Mac OS X, Linux, Solaris, and devices that support Java.

The tools for managing the server, changing the configuration, and managing user access that are part of Citrix Access Essentials are also as simple as possible: in my opinion, mastering them should not cause any difficulties for specialists involved in administering networks of small companies (Fig. 3). They allow you to perform almost any operation, up to customizing the appearance of the interface of the client part of this product (Fig. 4). In addition, the product is provided with very detailed documentation describing every administrator's action, from installing the server to optimizing its performance, configuring security settings and accessing external devices.

In other words, this product is really created taking into account the characteristics of small companies, including the limited funds for the use of services of highly qualified (and therefore expensive) IT specialists.

Licensing

Citrix Access Essentials is licensed as follows. The product is available as named licenses purchased for each user who will use the software. This product does not support either side-by-side usage or device or server licensing. The product can be purchased with or without a Subscription Advantage.

When using Citrix Access Essentials (as well as any other terminal access tools), you must also comply with the licensing rules for software that will be accessed in terminal mode license agreements of modern software tools usually provide certain rules for the use of products in a similar mode. In particular, often when working in this mode, the number of licenses purchased must be equal to the number of connected workstations, despite the fact that only one copy of the application is actually installed on the server.

Citrix Access Essentials and cost reduction

What costs can small and medium businesses avoid by implementing Citrix Access Essentials? The standard benefits of using terminal access tools, such as lower costs for maintaining the same type of workstations, their Hardware, in the case of small enterprises at first do not seem so obvious. But after all, the budget of such enterprises is small, so the ability to avoid unnecessary costs for support, even if not as significant as in large enterprises, is even more relevant for small companies. And providing additional security for access to corporate data for small businesses can be vital if data is leaked, the consequences for small companies can be much more serious than for large enterprises.

Of the costs that small companies that have implemented Citrix Access Essentials will be able to avoid, first of all, it is necessary to allocate the costs of transforming the existing IT infrastructure and introducing new solutions when expanding their business, for example, when opening new offices and branches. In this case, the implementation of terminal access to the corporate information systems available at the central office (such as enterprise management systems, warehouse, accounting or personnel records) usually turns out to be much simpler and cheaper than deploying an independent infrastructure in the branch and organizing data synchronization with the central office. . In addition, a relatively large part of modern small and medium-sized businesses employs so-called mobile employees, providing for which communication with offices, security of access to corporate applications and data, as well as control of these processes is a very difficult task, which will also help Citrix Access Essentials. Given the potential cost savings mentioned above, IT leaders in smaller companies should take a closer look at this product, as it may be able to solve the problems some of them face.

Providing clients with computing resources (processor time, memory, disk space) for solving problems. Technically terminal server is a very powerful computer (or cluster) connected via a network with terminal clients - which, as a rule, are low-powered or outdated workstations, or specialized solutions for accessing a terminal server. The terminal server is used for remote maintenance of the user with the provision of a desktop.

Work process

The terminal client, after establishing a connection with the terminal server, forwards the input data (keystrokes, mouse movements) to the latter and, possibly, provides access to local resources (for example, printer, disk resources, smart card reader, local ports (COM / LPT) ). The terminal server provides a working environment (terminal session) in which user applications are executed. The result of the server's work is transmitted to the client, as a rule, this is an image for the monitor and sound (if any).

Terminal Server Benefits

• Reduced administration time
• Increased security - reduced risk of insider hacks
• Reduced software and hardware costs
• Reduced energy consumption

• The concentration of all functionality within one (several) servers - the failure of any element between the application and clients (server, switches, SCS) leads to downtime for many users.
• The negative consequences of errors in the configuration and operation of the software are intensifying (the consequences of errors do not affect individual users, but all users of the server immediately)
• Licensing issues (some software does not support multiple users on the same computer or requires more expensive versions).

Licensing Issues

Under the terms of free software (such as the X Window System), there is no licensing issue. For software that provides license agreement limitation on the number of copies / users, there are difficulties.

The following licensing models can be used in a terminal server environment:

• Per seat (per device - per workplace) - a separate license is required for each device (thin client or workstation), regardless of the number of users. A similar scheme is used when licensing Terminal Services as part of Windows Server.
• Per user (per user) - a separate license is required for each user (regardless of the number of concurrent users).
• Per connection (competitive license) - a separate license is required for each connection, while the number of users / workstations does not play a role - the number of simultaneously served users is important. This licensing system is used by Citrix Metaframe. In this case, there is license pool, each new connection takes one license from the pool. The license is returned to the pool when the connection ends.

Many large software packages provide a special service - a license server (an application that records, issues and accepts licenses). In conditions large networks it is recommended to allocate licenses of a separate computer for the server (or several - for reservation).

Types of terminal servers

• Microsoft Windows Terminal Server (shipped with Microsoft Windows Server)
• Citrix Metaframe

Another way to increase the performance of enterprise applications and reduce infrastructure costs is to use a terminal server. Its use can significantly increase the speed of resource-intensive applications, such as 1C Enterprise, and is the only solution if you need to provide access to corporate applications to remote users (for example, branches or a director from anywhere via the Internet).

Due to certain specifics associated with multi-user work with applications, it is highly desirable to add the role of the terminal server as one of the first, at least before installing the application software.

It is recommended to use Windows Server 2003 or Windows Server 2008 as the base system, there are no fundamental differences in setting up the terminal server in these versions, so everything said is true for both systems. In our case, Windows Server 2003 SP2 will be used.

in a snap Managing this server choose Add or remove a role, the server setup wizard will start and, if we have not added roles yet, it will offer to use typical setting or special configuration. We select the second, in the next window we indicate Terminal Server and click Further.

At this stage, we need an installation Windows disk Server, which you should have on hand in advance, after the installation is completed, the server will be rebooted. After the reboot, we see that the terminal server role has been successfully added, but there is an inscription that since the terminal services licensing server was not found, the issuance of licenses will stop after 120 days. You need to install a license server. To do this, in a snap Installation and removal of programms choose Installing Windows Components and in the window that opens, check the box Terminal Server Licensing.

Now choose Start - Administrative Tools - Terminal Server Licensing. In the window that opens, select Action - Activate the server. Specify as the activation method Auto connection(Internet required) and fill out a short questionnaire. Provide information about the organization and email no numbers are required here, the activation itself is nominal and it is not entirely clear what meaning Microsoft puts into it.

When activation is complete, the CAL Wizard will launch. In the window Type of licensing select the licensing program corresponding to the available terminal licenses. For small firms, this is usually "Open License", before proceeding, make sure that all the necessary data is at hand.

The next step is to enter the license data as well as the number and type of purchased licenses. For more details on licensing schemes and types of applicable licenses, see . If everything is entered correctly, the status of our server will change to activated and it will be possible to view the number and type of licenses installed (as well as the number of licenses issued).

Having finished with licensing, we proceed to configure the terminal server itself. Start - Administrative Tools - Configuring Terminal Services. In the window that opens, we see the only this moment connection rdp-tcp, click right click and choose Properties. The first tab allows you to set the security level. If you intend to use the terminal server on the internal network, you can leave everything by default, otherwise you should translate Security level into position Coordination, A Encryption level set as High. However, keep in mind that clients that do not support given level security will not be able to connect to our terminal server. For example, the default client shipped with Windows XP SP2 does not meet these requirements and you will need to manually install the latest version of the client.

The next bookmark we are interested in is Remote control , configure it as shown in the figure below. This setting will allow, if necessary, to connect and interact with the user's session to resolve problems that arise.

Bookmark Network adapter we can choose the adapter with which this connection will be used. This allows you to create and assign different connections to different network interfaces, for example, we can create one connection with low security for the internal network of the enterprise, and the second with high security for clients connecting from the outside (via the Internet or VPN). And finally bookmark Permissions, if we do not intend to use multiple connections and differentiate user rights by groups, you can leave everything as it is, to access the terminal server it will be enough to add users to the group Remote Desktop Users. Otherwise, we add here the user groups we need and set their rights User Access + Guest Access. In this way, you can conveniently differentiate the use of connections by user groups, for example, giving access to the connection from the outside only to the Administrator and Management, and to all necessary groups to the internal one.

The terminal server is configured and after the installation of the software it will be ready to accept user connections. Here I would like to draw attention to one more subtlety: the entire installation of software for the terminal server should be done only through Add/Remove Programs - Install Programs.

Communication network is a channel for the exchange of information between its participants.

Depending on the participants' access to information, there are open, closed and combined types of communication networks. Open ones are characterized by the presence of controlling and stopping participants, closed ones are a channel for the free exchange of information. In the modern world, the combined type is most often used, in which only certain areas are subject to control.

Given the number and subordination of participants, communication networks can be divided into two types: linear and multilevel. The first type includes equal participants, the second has a hierarchy that can distort the information received by the end participants.

The most common model in large organizations communication network- an awning that involves horizontal and vertical communication channels. Thus, employees of the company can exchange information within the department, make independent decisions within their competence.

A classic example of a “circle” communication network is a small department of a company, each of whose employees reports directly to the manager.

The term " telecommunications" comes from the Greek tele - far, far away and the Latin communico - I make it common, I connect. It can be interpreted as a connection at a distance. Therefore, by a telecommunications network we will understand a set of means that ensure the transfer of information between two terminal devices (subscribers). The network includes :

Network equipment, which includes terminal devices (personal computers, servers, audio and video devices, network printers, fax machines, barcode readers, etc.) and communication equipment (wired, cable and/or wireless media, as well as intermediate devices such as network adapters, modems, repeaters, bridges, switches, etc.);

Support Tools network equipment. In such a complex system as a telecommunications network, it is necessary to have a wider arsenal of software, as well as standard sets (stacks) of communication protocols that determine the rules for the interaction of network devices.

The telecommunications network has a hierarchical structure that reflects the intensity of traffic between its individual nodes located in different buildings, settlements and regions. Network nodes are switches, which are multiport devices to which communication lines are connected.

Terminal devices of users are located on the periphery of the telecommunications network and constitute the lowest level of its hierarchy. Typically, the type of such devices determines the name of the network. The main terminal devices in computer network are computers, in the telephone - telephone sets, in the television network - television receivers, in the broadcasting network - radio receivers.

A thin client in computer technology is a computer or client program in networks with a client-server or terminal architecture that transfers all or most of the information processing tasks to the server. An example of a thin client is a browser-based computer used to run web applications.

In addition to the general case, it is necessary to single out a hardware thin client (for example, Windows and Linux terminals) - a specialized device that is fundamentally different from a personal computer (PC). A hardware thin client does not have a hard disk, uses a specialized local operating system (OS, one of the tasks of which is to organize a session with a terminal server for the user to work), does not include moving parts, and runs in specialized cases with completely passive cooling.

To expand the functionality of a thin client, they resort to “thickening” it, for example, adding offline work capabilities, while maintaining the main difference - working in a session with a terminal server. When moving parts (hard drives) appear in the client, opportunities arise battery life, it ceases to be a thin client in its purest form, but becomes a universal client.

A thin client in most cases has a minimal hardware configuration; instead of a hard disk, DOM is used to load a local specialized OS (DiskOnModule - a module with an IDE connector, flash memory and a chip that implements the logic of a conventional hard disk - is defined in the BIOS as a normal HDD, only its size is usually 2-3 times smaller). In some system configurations, the thin client boots the operating system over the network from a server using the PXE, BOOTP, DHCP, TFTP, and Remote Installation Servic protocols.

Terminal access - access to information system(IS), organized so that the local machine-terminal does not perform computational work, but only redirects input information (from the mouse and keyboard) to the central machine (terminal server) and displays graphic information on the monitor. Moreover, all computational work in the terminal system is performed on the central machine.

As shown above, historically, terminal access was first organized on computers capable of serving several computing processes simultaneously. This made it possible to distribute computing resources more rationally among the users of the first very expensive computers. With the advent of cheap personal computers, the role of terminal access began to decline somewhat, as it was believed that sufficient IS performance could be obtained on the desktop of each PC user.

However, later it became obvious that the cheapness of a PC is not able to compensate for the daily costs of maintaining a large number of user workstations, which allegedly have advantages due to the possibility of personalizing the settings of operating systems and software (SW). Realistically (in large organizations), the presence of a large number of "motley" equipment instead of advantages creates additional difficulties for users and system administrators. The issues of ensuring the security of IP also required a revision of views and a return to terminal access, as more unified and economically justified.

User workstations are equipped with "thin client" terminals - inexpensive and simple specialized devices that occupy a minimum of space, are silent and practically do not require maintenance. They can be computers without an installed operating system and programs (everything is loaded from the server), which are only an input and display device for information. Almost any computer with a Celeron 300 MHz processor, 64 MB of RAM, and a hard drive is not necessary as a terminal. All applications run on the server, only screen updates are transmitted to the client over the network, and keystrokes and mouse movements are transmitted from the client to the server. Appearance personal computer and thin client is shown in Fig. 2.1.

Figure 2.1 - Appearance of a thin client (on the right) in comparison with a traditional desktop PC

Terminal network- this is the principle of building a computer network and working in it, which is characterized by speed, reliability and economy in comparison with a "normal" office network.

terminal server – a computer with a specially configured server operating system Windows 2003 Server and installed programs 1C: Enterprise, Word, Excel, and others.

For the terminal user, everything looks as if a computer, equal in power to the server, was standing on his desk. You can connect dozens of terminals to one server and none of the users notice that the server is being used by someone else. In the terminal network 1C: Enterprise and other databases work much faster.

From the user's point of view, working with a thin client has only one difference from working with a traditional PC. That difference is silence. There is not a single source of noise in the thin client because there is not a single moving part.

A variant of the block diagram of a network built on these principles is shown in fig. 2.2.

Figure 2.2 - Structural diagram of the terminal network

2.2 Local network tools based on "thin clients"

Currently, a wide range of thin clients are produced, which differ in characteristics and cost.

Number of users in local network depends on the operating system loaded on the server. For example:

Windows XP - allows you to serve 10 thin clients;

Windows 2003 Server - allows you to serve 70 thin clients;

Windows 2008R2 - allows you to serve up to 100 thin clients.

The distance between clients and server is usually up to 100m. The connection of clients to the server is cabled or wireless, for example, using Wi-Fi technology.

For example, Russian-made OPTION Wi-Fi thin client device has the following characteristics. Power supply power: 5V1A consumed 4-5W.

Minimum requirements: P4 2.0 or higher 512M memory; overall dimensions: 14.5 * 14.5 * 3.2 (cm); weight: 220 gr.

Interface: PS/2 VGA LAN DC SPk USB.

OS support: Windows 2000 Windows XP Windows 2000/2003/2008 Server, Windows 7.

The server in the terminal network performs a triple function:

First of all, it is a file server that provides centralized storage of station configuration files and all user files. It also suggests running an http server on it, software that organizes the exchange of mail messages, and a SQL server (in case the process of using the network reaches the proper height);

In addition, the server acts as a kind of "application server", because it is on it, in fact, that most of the tasks launched by users are performed. From which it follows that he must have user accounts corresponding to the users of the stations. Moreover, the home directories of these users must contain configuration files that determine the execution of the necessary applications;

Finally, the server is used as the only workstation in the network, where all installed applications can be launched. In fact, the algorithm for "expanding" the functionality of the network is as follows: the administrator, if necessary, installs one or another application on the server.

Servers are different and they perform completely different tasks. The range of tasks, and, accordingly, the requirements for a particular server, depend on the role that the server will play in the information and telecommunications (IT) infrastructure of the organization. Below we will consider two types of servers: a file server and a terminal server. The first is required when using desktop PCs at workplaces, the second - when using thin clients at workplaces.

The file server solves a fairly simple task - it provides users with access to their work information.

The terminal server solves a more complex problem - it provides users, in addition to access to their information, a full-fledged working environment in which user applications are executed.

The requirements for the file server are not high - a sufficient level of information storage reliability at a reasonable price (which is achieved using a RAID level 1 array and inexpensive hard drives type Serial ATA in the disk subsystem) and normal server availability, which is achieved by using entry-level server components.

The requirements for a terminal server are much higher. He must:

Provide access to information 24 hours a day, 365 days a year (which is achieved by using server hard drives and using a RAID level 5 array);

Provide a comfortable working environment for every user.

The last point is the most interesting for us, since it determines the performance requirements of the server. The starting point in this case is the number of jobs.

Processors. To serve 50 thin clients, a 2-processor configuration based on Intel Xeon class processors with an 800 MHz bus is necessary and sufficient.

RAM. 256 MB of memory is required for the operation of Windows 2003 Server, 64 MB is required for each session.

Thus, the first 1 GB of memory can serve 12 thin clients, each subsequent 1 GB - 16 thin clients. 4 GB of RAM, respectively, allow us to provide comfortable operation of 50 or more thin clients.

HDD. 25 GB of disk space will be required for the OS and applications. It is enough for each user to allocate 100 MB.

2.3 Advantages and disadvantages of using "thin clients" in the network

No moving parts. The more moving parts, the more likely one of them will break. There are no moving parts in thin clients, so the normal lifespan for each device is 8 years.

Ease of maintenance. Thin clients require minimal attention from the administrator. There is actually nothing to set up in them, and there is nothing to break, even physically. All settings are made on the server. Visiting the room where the factory-made thin clients are located is only necessary to check the condition of the mice, keyboards, and peripherals.

High administration efficiency. The system administrator, without getting up from his workplace, can set up all the necessary security policies, clearly and unambiguously delineate the rights of different user groups. No need to bypass all computers, setting up something on each of them. Thin clients allow you to centrally solve the problems of security and differentiation of access rights for various categories of users. This greatly increases the efficiency of administration.

100% safety of information in the course of work. The thin client only displays information and processes user actions. All information is on the server. And if for some reason the session of the terminal client is suddenly terminated, the information will remain in its place. The next time the user connects, he will see the document that he was working with before the accident, and in the form in which the document was at the time of the accident. Not a single byte will be lost. Moreover, it does not matter where the accident occurs - in the cable, at the level of network switching equipment or the thinnest client. The information will be stored on the server. By the way, another consequence is that thin clients do not need an uninterruptible power supply. Interruptions in the power supply of thin clients do not lead to the loss of information, nor to the failure of the devices themselves. Centralization of data storage simplifies backup procedures and guarantees data recovery.

Ultra low power consumption. A "cold" processor, the absence of fans and other motors, hard drives and drives, flash memory with meager power consumption - thanks to all this, the thin client consumes extremely little power compared to a conventional PC. The difference can be tenfold. In other words, 1 regular, traditional PC consumes as much power as 100 thin clients.

All necessary functionality. Thin clients are equipped with USB ports, which allows you to connect the necessary peripherals to them. And the “network” nature of thin clients makes it easy to use network printers that are present on the network. And, of course, any storage medium (or device for working with them) can be easily connected to the thin client via the USB interface. It should also be noted that the possibility remote access to the "workplace".

Ease of expansion of the information system. Thin clients make it easy, with minimal effort and time, to expand the information system, increasing the number of jobs. In order for the thin client to start working fully, two sockets are needed: an electrical outlet and a local network. No need to install OS, no need to install drivers, no need to install and configure software. You just need to connect the thin client to two outlets. And the very growth of a network of thin clients is limited only by the capabilities of the server subsystem, which is easily expanded.

Low risks of ownership. An ordinary computer can be stolen - the system unit can be taken out quite easily, especially since standard cases are not equipped with any elements of protection against theft. Stealing thin clients is stupid and pointless.

High economic efficiency. Statistics are stubborn things. She says that up to 77% of the cost of owning a product is the cost that businesses incur after purchasing the product. This includes costs for: maintenance, repairs, spare parts, downtime due to product inoperability, management, etc. And only 23% of the cost of owning a product is the cost of acquiring it. At the same time, thin clients are cheaper than PCs and provide the lowest cost of ownership. They do not require the purchase of a license for the operating system, its cost is already included in the cost of the device, and the cost of TC CAL (Terminal Server Client Access License) is almost 2 times lower than the cost of Windows XP Pro OEM for PC. Thin clients will last 2-4 times longer, require a minimum of attention from service personnel, and greatly facilitate the administration and maintenance of an information system. Finally, thin clients minimize the risks of information loss due to various accidents, minimize power consumption, their use significantly reduces the noise level in the room, and the risk of theft of such devices tends to zero.

performance. When working in a "normal" office network with the 1C:Enterprise program and other databases, a large amount of information is transmitted over the network, which slows down the execution of programs in proportion to the number of jobs. In the terminal network, all programs are executed on the server, and only the screen view is transmitted over the network. Network traffic will be minimal, and there will be no slowdown in program execution even with a large number of jobs.

Disadvantages of building a network based on thin clients. One of the main ones is the increased requirements for the performance and reliability of the terminal server, since its failure leads to the inoperability of the entire network.

This problem is solved by using several servers and load balancing between them. Also, resource-intensive applications for working with graphics and three-dimensional modeling, such as Photoshop, AutoCAD, 3D Studio Max, are not applicable in the “thin client” technology. For these tasks, you will have to use specialized powerful workstations. Video conferencing becomes very problematic, but latest version Citrix MetaFrame Presentation Server has special tools to overcome this problem, although this technology is very expensive

2.4 Comparative characteristics of network building options

The results of comparing some factors of building networks based on thin clients with a traditional solution based on standard PCs are presented in Table. 2.1. This table presents the benefits of using thin client technology to build corporate infrastructure over standard personal PCs.

Table 2.1 - Benefits of using thin client technology

The cost of maintaining and operating an information system is 77% of the total cost of ownership of a product such as an information system. Naturally, this is an average figure and it can be significantly reduced. For what?

First of all, let's pay attention to the life of the equipment. Since there are no moving parts in thin clients, the probability of failure tends to zero, and the estimated service life is considered to be a time period of 8-10 years. After this period, thin clients do not break at all, by the way, they simply become obsolete. The service life of conventional personal computers is much shorter, and the problem of their moral obsolescence arises after 3 years. In addition, it must be understood that the life of a PC depends significantly on the quality of the components used and the quality of preventive maintenance. Moreover, the lack of such maintenance significantly increases the likelihood of early failure of computers. And its presence in full can significantly extend the life of the PC. However, the cost of such maintenance is quite high and significantly increases the total cost of ownership of an organization's information system. Note that the cost of annual support for an information system using thin clients is 80% less than the cost of maintaining an IT infrastructure built using standard PCs.

Let's analyze the cost of maintenance of the information system. Maintenance of thin clients comes down to replacing external power supplies, keyboards and mice in case they fail. All. Nothing more needs to be done in the workplace. When maintaining a PC fleet, everything is much more complicated. Firstly, it is necessary to carry out regular preventive maintenance of each system unit, removing accumulated dust and dirt, lubricating the fan on the processor. Secondly, after three years of operation, the cost of replacing parts that have failed, that is, the cost of repairs, increases significantly. Thirdly, the larger the PC fleet, the more qualified specialists are needed for maintenance. Of course, the staff may not be increased, but then the IT department at some point in time will be forced to focus solely on PC maintenance and will cease to fulfill its main role. A key function of IT professionals in any organization is to optimize work processes through the introduction of information technology and, in the future, improve the efficiency of work processes by improving the information system of an enterprise or organization. Giving IT specialists the sole task of maintaining the existing information system of an organization is an extremely dangerous decision, since without the development of an information system today it is impossible to develop an organization or improve its work processes.

An important place in the operation of the network is the cost of administration. In the case of using personal computers in the workplace, the cost of administration is quite high. Why? IT infrastructure is usually built incrementally. As a result, different workstations have PCs with different configurations. As a result, each PC requires some attention from the system administrator. And when it comes to a computer park that exceeds at least 50 units, the organization begins to experience problems. A system administrator who is able to effectively configure a large number of PCs will be quite expensive. Of course, in some places where information technology is not a core subject, there are examples of courageous and effective struggle of IT departments with the problems that a regular PC brings them. However, in commercial organizations, the courageous and effective struggle with problems is possible only if there is sufficient motivation (usually financial), which means that each system administrator will have to pay significant money. Or - to lose thousands of dollars daily due to downtime, failures, breakdowns and "glitches", as happens in companies that save on normal system administrators, preferring "enikey" employees to them. Tonika clients allow you to use a significantly smaller number of system administrators through the use of a ready-to-use management solution - Altiris deployment solution. Yes, these administrators must be experts in their field, but the information system will perform its tasks perfectly, and they will have enough resources to work on improving its efficiency.

And the last one is power consumption. The power consumption of an average modern computer is over 150 watts. Energy is consumed by a powerful processor and a fan that cools it. The hard drive, optical drive, memory, modern chipsets, fans in the power supply, on the north bridge and in the case actively consume energy. The video subsystem noticeably consumes energy, even if it is built into the chipset. At the same time, the thin client consumes an average of 15 Wh. There are slightly more "gluttonous" models, there are less "gluttonous" models, however, in general, the difference in power consumption is very, very noticeable. It is easy to calculate that when using thin clients, energy savings will be about 135 Wh per hour per 1 workplace. If the organization has 100 jobs, then the transfer of the information system to thin clients will provide savings of 13.5 kWh per hour. It is enough to multiply this figure by the number of working hours per day to get the daily savings. For example, if the computer park is 300 PCs, then transferring the information system to thin clients will save 40.5 kWh of electricity per hour. With an 8-hour working day, the savings in just one day will be 324 kWh.

All of the above allows us to conclude that the implementation of networks based on thin client technology is significant cost-effectiveness.