Due to the large area of ​​the territory, the large number of buildings, workshops, departments and users (about 1500 users), in order to increase the performance and fault tolerance of the network, it is necessary to divide it into logically independent objects, which will be interconnected by node network devices. At the same time, dividing a large network into smaller ones will make it easier to administer. Thus, the enterprise LAN topology will be designed in the form of a hierarchical star. The link layer technology will be a family of high-speed versions of Ethernet.

To ensure separation of responsibilities between switches, a standard architecture will be used, consisting of: network core level switches, distribution level switches and access level switches. Switches installed at the network core level require high performance and fault tolerance. Since the performance of the entire network will depend on them. Distribution switches will be located throughout the enterprise, closer to groups of access switches, to which end users of LAN resources are already connected. Server cabinet switches are connected directly to the network core switch, which serve the so-called SAN (Storage area network), local networks inside the server cabinets.

The enterprise is divided into 5 zones, each of which will be served from its own distribution level switch. Zones are selected depending on location and number of users. The enterprise LAN diagram is shown in Figure 2.

Logically, such a large network should be divided into several smaller networks. With this approach, network performance will increase, since broadcast and other “junk traffic” will not spread across all networks, taking up network bandwidth. In the event of a network failure, such as a broadcast storm, only a small logical fragment of the network will fail, the problem in which can be identified and corrected much faster. That is, in this case, the convenience of network administration is ensured. When carrying out any work to rebuild the network, it will be possible to do this in parts, which simplifies the work of network administrators and allows a small number of users to be taken out of service while the work is being carried out.

Figure 2 - Enterprise LAN topology

Virtual local area network (VLAN) technology will be used to divide the network. Each division, and sometimes a group of smaller divisions, will have its own virtual network. Several vlans will also be created to connect the switches of the network core and the distribution layer. Each such network will use unique network addresses. Virtual networks will use switch ports at the core and distribution levels to place units in their own unique vlans. This will be done during the configuration of active network devices.

As can be seen from the diagram, several logical channels will be used to connect the core and distribution switches. The core topology of the “star + ring” network will be implemented. From the core switch, channels radiate in a star pattern to the distribution switches; they are highlighted in blue in the diagram. This creates a “star”. These channels will be allocated to a separate vlan, which will be used only for communication between backbone switches.

The channels that will connect the backbone switches into a “ring” are highlighted in yellow. Previously, it was not acceptable to create loops in Ethernet networks. But the requirements for network reliability led to the development of technologies capable of supporting redundant connections in the network for channel reservation. Ethernet Ring Protection Switching (ERPS) is one of the technologies that allows you to organize fault-tolerant network topologies. It was chosen over Rapid Spanning Tree Protocol (RSTP) due to the quick time it takes to restore the network in the event of a failure of one of the channels. For RSTP the convergence time is less than 10 seconds, while for ERPS it is less than 50 milliseconds. This will also be a separate vlan, used only by backbone switches.

Dynamic routing will be used to unite all virtual networks and find routes between them. Namely, the Open Shortest Path First version 2 (OSPFv2) protocol. Each of the backbone switches will be able to operate at layer 3 of the OSI model, that is, it will be an L3 switch. In the OSPF protocol domain, one backbone zone will be allocated - the backbone. It will contain only routers (built into L3 switches), which will exchange information with each other about the virtual networks connected to them. This protocol requires the allocation of the OSPF domain root - Designated root (DR), and the presence of a backup root - Backup designated root (BDR). A core-level switch will be used as a DR, and one of the distribution-level switches will be used as a BDR.

Each user access layer switch will be used in its own specific vlan allocated for it on the distribution layer switch. In some cases, such switches can be used to connect switches with fewer ports to them, but this does not matter for the logic of the network.

In this way, a productive, fault-tolerant and easily scalable local area network architecture is organized.

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Introduction

1.3 Network management method

1.4 Network architecture

2.1

2.4 Organization structure

2.5 Administration and management strategy

3. Calculations of creation costs

Conclusion

List of used literature

Note

Introduction

The modern era is characterized by the rapid process of informatization of society. This is most clearly manifested in the growth of throughput and flexibility of information networks. Bandwidth per user is increasing rapidly due to several factors. Falling prices for computers lead to an increase in the number of home PCs, each of which potentially turns into a device capable of connecting to the Internet. New network applications are becoming more demanding in terms of bandwidth - Internet applications focused on multimedia and video conferencing are becoming common practice, when a very large number of data transmission sessions are opened simultaneously. As a result, there has been a sharp increase in the consumption of Internet resources - it is estimated that the average volume of information flow per user in the world increases 8 times every year.

The relevance of writing a course project is due to the fact that the relatively low complexity and cost of LANs, using mainly PCs, ensure widespread use of networks in the automation of commercial, banking and other types of activities, office work, technological and production processes, for the creation of distributed control, information and reference, control and measurement systems, industrial robot systems and flexible manufacturing. In many ways, the success of using LANs is due to their accessibility to the mass user, on the one hand, and the socio-economic consequences that they bring to various types of human activity, on the other hand. If at the beginning of their activity LANs exchanged inter-machine and inter-processor information, then at subsequent stages, in addition to this, text, digital, visual (graphic), and speech information began to be transmitted to the LAN.

The main goals of local network design are:

1. Collaborative information processing;

2. File sharing;

3. Centralized computer management;

4. Control over access to information;

5. Centralized backup of all data;

6. Shared access to the Internet.

To organize a LAN, the computer must have:

1. Network adapter.

2. A cable that connects either to an intermediate network element or directly to the host computer/server.

3. Network operating system or software that enables network connections.

Relations arising during the development, installation, operation and performance of work or provision of services, as well as requirements for the functioning of the unified communication network of the Russian Federation related to ensuring its safety, integrity and stability are regulated by the Federal Law of December 27, 2002 No. 184-FZ "On technical regulation".

The general rules for the formation, maintenance and application of the provisions of the standardization system in the Russian Federation are regulated by GOST R 1.0-2004 "Standardization in the Russian Federation. Basic provisions"

General requirements for the design of the main elements of a structured cabling system based on twisted pair conductors and fiber-optic components are regulated by GOST R 53246-2008 "Structured cable systems"

Premises where automated workstations are located must be equipped in accordance with SanPiN 2.2.2/2.4.1340-03.

Distribution of tasks between Internet cafe LAN servers:

A file server is a dedicated server designed to perform file I/O operations and store files of any type. As a rule, it has a large amount of disk space, implemented in the form of a RAID array to ensure uninterrupted operation and increased speed of writing and reading data.

Web server - A server that accepts HTTP requests from clients, usually web browsers, and provides them with HTTP responses, usually along with an HTML page, image, file, media stream, or other data.

A web server refers to both the software that performs the functions of a web server and the computer itself on which this software runs.

DNS server is an application designed to respond to DNS queries using the appropriate protocol. A DNS server can also be called the host on which the application is running.

DHCP is a network protocol that allows computers to automatically obtain an IP address and other parameters necessary to operate on a TCP/IP network. This protocol operates on a client-server model. For automatic configuration, the client computer, at the network device configuration stage, contacts the so-called DHCP server and receives the necessary parameters from it. The network administrator can specify the range of addresses distributed by the server among computers. This allows you to avoid manual configuration of network computers and reduces the number of errors. The DHCP protocol is used on most TCP/IP networks.

VPN is a generalized name for technologies that allow one or more network connections (logical network) to be provided over another network (for example, the Internet). Despite the fact that communications are carried out over networks with a lower or unknown level of trust (for example, over public networks), the level of trust in the constructed logical network does not depend on the level of trust in the underlying networks due to the use of cryptography tools (encryption, authentication, public key infrastructure, means to protect against repetitions and changes transmitted over the logical network of messages).

Formulation of the problem

Given: two classes of personal computers, 6 each. (No. 1) and 7 pcs. (No. 2), printing center No. 3 with 5 PCs, as well as 4 printers.

It is necessary: ​​to organize a full-fledged LAN with Internet access (only for users of classes No. 1 and No. 2), and also to provide for the possibility of sharing network resources (printers) with all authorized network users.

Figure 1 - Layout plan.

Chapter 1. Planning the LAN structure

1.1 Analysis of the information needs of the enterprise

The Internet services market is currently developing rapidly and actively. The Internet has firmly entered the life of almost every person and is an integral part of our daily life. The services offered by the World Wide Web are used everywhere: at home, at work, on the way to work via telephone, during leisure, etc. Cafes are opening where you can not only take a break from everyday life, but also use the Internet or packaged programs on a personal computer, and play online games. Such services are provided by an Internet cafe.

Information flows in the enterprise LAN

Information will be transmitted between all computers installed in the Internet cafe. Also, any computer will have access to printers. But only users of classes No. 1 and No. 2 will be able to access the Internet.

1.2 Network structure planning

A computer network is a collection of computers and various devices that provide information exchange between computers on the network without the use of any intermediate storage media.

The entire variety of computer networks can be classified according to a group of characteristics:

1. Territorial distribution;

2. Departmental affiliation;

3. Information transfer speed;

4. Type of transmission medium.

According to the territorial distribution, networks can be local, global, and regional. Local networks are networks that cover an area of ​​no more than 10 m2, regional networks are located on the territory of a city or region, global networks are located on the territory of a state or group of states, for example, the World Wide Web Internet.

By affiliation, departmental and state networks are distinguished. Departmental ones belong to one organization and are located on its territory. Government networks are networks used in government agencies.

Based on the speed of information transfer, computer networks are divided into low-, medium- and high-speed.

Based on the type of transmission medium, they are divided into coaxial networks, twisted pair networks, fiber optic networks, with information transmission via radio channels, and in the infrared range.

Computers can be connected by cables to form different network topologies. The topology of a computer network refers to the way in which its individual components (computers, servers, printers, etc.) are connected. There are three main topologies:

1. Star topology;

2. Ring type topology;

3. Common bus type topology.

When using a star topology, information between network clients is transmitted through a single central node (Figure 2). A server or a special device - a hub (Hub) can act as a central node.

Figure 2 - Star topology.

The advantages of this topology are as follows:

1. High network performance, since the overall network performance depends only on the performance of the central node;

2. No collision of transmitted data, since data between the workstation and the server is transmitted over a separate channel without affecting other computers.

However, in addition to the advantages, this topology also has disadvantages:

1. Low reliability, since the reliability of the entire network is determined by the reliability of the central node. If the central computer fails, the entire network will stop working;

2. High costs for connecting computers, since a separate line must be installed for each new subscriber.

In a ring topology, all computers are connected to a line closed in a ring. Signals are transmitted along the ring in one direction and pass through each computer (Figure 3).

Figure 3 - Ring type topology.

The transmission of information in such a network occurs as follows. A token (special signal) is transmitted sequentially, from one computer to another, until it is received by the one that needs to transfer the data. Once the computer receives the token, it creates what is called a "packet" in which it places the recipient's address and data, and then sends the packet around the ring. The data passes through each computer until it reaches the one whose address matches the recipient's address.

After this, the receiving computer sends confirmation to the information source that the data has been received. Having received confirmation, the sending computer creates a new token and returns it to the network.

The advantages of the ring topology are as follows:

1. Forwarding messages is very efficient because... You can send several messages one after another in a ring. Those. A computer, having sent the first message, can send the next message after it, without waiting for the first one to reach the recipient.

2. The length of the network can be significant. Those. Computers can connect to each other over considerable distances, without the use of special signal amplifiers.

The disadvantages of this topology include:

1. Low network reliability, since the failure of any computer entails the failure of the entire system;

2. To connect a new client, you must disable the network;

3. With a large number of clients, the speed of the network slows down, since all information passes through each computer, and their capabilities are limited;

4. Overall network performance is determined by the performance of the slowest computer.

With a common bus topology, all clients are connected to a common data transmission channel (Figure 4). At the same time, they can directly come into contact with any computer on the network. The transmission of information in this network occurs as follows. Data in the form of electrical signals is transmitted to all computers on the network. However, the information is received only by the computer whose address matches the recipient's address. Moreover, at any given time, only one computer can transmit data.

Figure 4 - Common bus type topology.

Advantages of the common bus topology:

1. All information is online and accessible to every computer;

2. Workstations can be connected independently of each other, i.e. When connecting a new subscriber, there is no need to stop the transmission of information on the network;

3. Building networks based on a common bus topology is cheaper, since there are no costs for laying additional lines when connecting a new client;

4. The network is highly reliable, because The performance of the network does not depend on the performance of individual computers.

The disadvantages of a common bus topology include:

1. Low data transfer speed, because All information circulates through one channel (bus);

2. Network performance depends on the number of connected computers. The more computers are connected to the network, the slower the transfer of information from one computer to another;

3. Networks built on the basis of this topology are characterized by low security, since information on each computer can be accessed from any other computer.

The most common type of network with a common bus topology is an Ethernet standard network with an information transfer rate of 10 - 100 Mbit/s.

The main LAN topologies were reviewed. However, in practice, when creating an organization's LAN, a combination of several topologies can be used simultaneously. For example, computers in one department can be connected according to a star scheme, and in another department using a common bus scheme, and a communication line is laid between these departments.

In this project, a star topology will be used to organize a LAN for an Internet cafe.

1.3 Network management method

There are two models of local area networks:

1. Peer-to-peer - WORKGROUP;

2. Client-server - Active Directory.

These models determine the interaction of computers in a local area network. In a peer-to-peer network, all computers have equal rights with each other. In this case, all information in the system is distributed between separate computers. Any user can allow or deny access to data stored on their computer.

WORKGROUP

Workgroup is an independent solution for organizing a computer network for a small number of community of computers, which has a peer-to-peer architecture and the authentication process in which occurs on the basis of a local database stored on each of the computers in the workgroup

In a peer-to-peer network, a user working on any computer has access to the resources of all other computers on the network. For example, sitting at one computer, you can edit files located on another computer, print them on a printer connected to a third, and run programs on a fourth.

The advantages of this model of organizing a LAN include ease of implementation and savings in material resources, since there is no need to purchase an expensive server.

Despite the ease of implementation, this model has a number of disadvantages:

1. Low performance with a large number of connected computers;

2. Lack of a unified information base;

3. Lack of a unified information security system;

4. Dependence of the availability of information in the system on the state of the computer, i.e. If the computer is turned off, then all information stored on it will be inaccessible.

Active Directory

Active Directory allows administrators to manage all declared resources from one workstation: files, peripheral devices, databases, connections to servers, access to the Web, users, services.

In networks with a DNS deployment, it is highly recommended to use directory service-integrated core zones to support Active Directory, which provide the following benefits:

1. Main server update and advanced security features based on Active Directory capabilities.

2. Replication and synchronization of zones with new domain controllers occurs automatically each time a new controller is added to the Active Directory domain.

3. By storing DNS zone databases in Active Directory, you can streamline database replication across your network.

4. Directory replication is faster and more efficient than standard DNS replication.

Because Active Directory replication occurs at the individual property level, only necessary changes are propagated. However, directory service-integrated zones use and send less data.

The advantages of this model include:

1. High network speed;

2. Availability of a unified information base;

3. Availability of a unified security system.

However, this model also has disadvantages. The main disadvantage is that the cost of creating a client-server network is significantly higher due to the need to purchase a special server. Another disadvantage is the presence of an additional need for service personnel - a network administrator.

For this organization, a local area network was chosen based on a client-server model. The server in this organization will be presented in the form of a computer from class No. 2, to which only the management staff of the Internet cafe will have access. The server will be placed in a special computer cabinet for protection.

1.4 Network architecture

The main components from which the network is built:

1. Transmission medium - coaxial cable, telephone cable, twisted pair, fiber optic cable, radio air, etc.;

2. The switch is used to connect several nodes of a computer network;

3. Router - a device designed to access the global network;

4. Workstations - PC, workstation or network station itself. If the workstation is connected to a network, it may not require a hard drive or floppy disks. However, in this case, a network adapter is required - a special device for remotely loading the operating system from the network;

5. Interface cards - network cards for organizing the interaction of workstations with the network;

6. Servers - individual computers with software that perform the functions of managing shared network resources;

Network software.

Network resources presented in the form of 4 printers on each floor (Figure 5). Any Internet cafe user can use any of them without leaving his workplace.

information network operational internet

Figure 5 - Network printer.

Chapter 2. Organization of a local computer network

2.1 Networking based on operating system

Selecting a network OS. Features of this OS

There are many operating systems, and each has its own degree of prevalence. Some systems are more convenient for working on a network, while others are more convenient for offline work, since it is difficult to combine everything without losing speed and stability. Each operating system has advantages and disadvantages. Examples of OS are Windows 2000, Windows XP, Windows 2003 Server, Windows Vista, UNIX, Linux, Sun Solaris, Novell Netware, FreeBSD, etc. Let's look at the most popular operating systems.

Windows 2000. Windows 2000 is one of the software products of Microsoft Corporation. This operating system has proven itself to be a stable platform, so it is mainly installed on servers. Windows 2000 is the successor to Windows NT, which was famous for its fault tolerance, security, network capabilities and was used on servers and home computers. Having received the interface from Windows 98, advanced multimedia capabilities, the latest version of integrated directx software, etc., Windows 2000 has gained popularity among users.

Microsoft has released several versions of this operating system: Windows 2000 Professional, Windows 2000 Server and Windows 2000 Datacenter.

The first was intended for use on home computers, the second and third - for installation on servers. Windows 2000 had shortcomings, the main of which were its demands on resources and shortcomings in graphics. However, due to its high fault tolerance, this operating system has been used on servers for a long time.

Windows XP. Windows XP followed Windows 2000. It appeared at the end of 2000 as Windows Net 1.0 (codenamed Whistler) - so the manufacturers emphasized that it was focused on networking. Microsoft marketers decided to change the name of the system to Windows XP (from the word experience). Her appearance caused quite a stir. There are several variants of Windows XP: Home Edition, Professional and Server, each of which has its own focus and has many advantages. This operating system is developed on the basis of a 32-bit kernel, which allows you to efficiently organize the operation of applications. There is even a 64-bit version of the system, oriented accordingly to 64-bit processors, which have become increasingly widespread lately. Windows XP features an improved system file protection system, support for new devices, an integrated voice command recognition system, etc. Users liked the operating system interface, which became fully customizable. The loading speed deserves respect, which is incomparable even with the lightest version of Windows 2000. The Windows XP desktop makes serious demands on computer resources, but its advantages and the level of power of modern components make it possible not to pay attention to this.

Windows Vista is another development by Microsoft in the field of operating systems. The new operating system contains many additions - a new Internet Explorer, a task scheduler, a powerful search engine and three-dimensional display of running applications (Flip 3D), a new approach to using drivers, etc. The loading speed of Windows Vista is even surprising. However, to fully enjoy the graphical capabilities of the interface, you must have a video card with hardware support for directx version 9.0, so the new system features two interfaces - Aero Express and Aero Glass. The first allows you to run the system on laptops, the second is designed to please users of modern computers. Unexpectedly, the implementation of a fundamentally new model for using drivers. To change, for example, the video card driver, you do not need to reboot the system. The superfetch mechanism deserves respect, allowing you to speed up the startup of the operating system. Windows Vista is a promising but resource-intensive system that won't see widespread adoption any time soon.

Windows 7 is a version of the computer operating system of the Windows NT family, following Windows Vista. In the Windows NT line, the system bears version number 6.1. The server version is Windows Server 2008 R2.

Windows 7 includes some developments excluded from Windows Vista, as well as innovations in the interface and built-in programs. Windows 7 has six editions: Starter, Home Basic, Home Premium, Professional, Enterprise, Ultimate ). The initial edition (Windows 7 Starter) will be distributed exclusively with new computers; it will not include functional parts for playing H.264, AAC, MPEG-2. Home Basic - intended exclusively for release in developing countries, it does not have the Windows Aero interface with Peek, Shake and taskbar preview functions, Internet connection sharing and some other functions. It also has the same viewing restrictions as the initial edition. In professional, enterprise and maximum versions there is support for XP Mode (on some processors). All editions include both 32-bit and 64-bit versions. All 32-bit versions support up to 4 GB of RAM (support for larger amounts of memory is only available when upgrading to the 64-bit version). 64-bit versions support up to 8 GB (Home Basic), up to 16 GB (Home Advanced), and up to 192 GB of memory in all other editions.

Windows 2003 Server. This operating system is a server implementation focused on organizing and controlling a local network, for which it contains the necessary control mechanisms. The reason for the appearance of this operating system is the presence of serious competitors in the server operating systems market. The corporation's management tried to develop a more advanced operating system. The result was the appearance in the summer of 2003 of Windows 2003 Server Standard Edition, Windows 2003 Server Enterprise Edition, Windows 2003 Server Datacenter Edition and Windows 2003 Server Web Edition. Each of the modifications is focused on the most effective network support in a specific case. For example, Windows 2003 Server Standard Edition is intended for installation on small business office servers, and Windows 2003 Server Enterprise Edition, which supports multiprocessor systems with any type of processor, is intended for installation on enterprise machines of any level. Windows 2003 Server lacks various multimedia add-ons and features, but many home users who value stable system operation install it.

Microsoft Windows Server 2008 (codename "Longhorn Server") is a version of the server operating system produced by Microsoft. Released February 27, 2008. It replaced Windows Server 2003 as a representative of the new generation of operating systems of the Vista family. Windows Server 2008 is the first Windows operating system released with built-in Windows PowerShell, an extensible command-line shell and accompanying scripting language developed by Microsoft. Compared to Windows Server 2003, the interface of Windows 2008 Server has been significantly changed and is similar to the Aero style found in Windows Vista. In addition, Windows Server 2008 can be installed without any GUI at all, just the services that are really needed. In this case, the server is managed in console mode. However, it is worth considering that the console mode is not full-fledged, as in Unix-like OCs, but is launched in a window (minimal gui will still work.

Windows Server 2012 (codenamed "Windows Server 8") is a version of the server operating system from Microsoft. Belongs to the Microsoft Windows OS family. It was released on September 4, 2012 to replace Windows Server 2008 R2 as the server version of Windows 8. It is available in four editions.

Windows Server 2012 is the first version of Windows Server since Windows NT 4.0 that does not support Itanium processors. Key improvements: new Modern UI, 2,300 new Windows PowerShell cmdlets, improved task manager, new IPAM (IP Address Management) role for managing and auditing IP4 and IP6 address space, improvements to Active Directory, etc.

Linux. Created in 1992 by amateur programmer Linus Torvalds, this operating system is unlike any other out there.

Firstly, Linux is open source, meaning it is distributed free of charge. Any user familiar with programming can correct it or report the solutions found to the creator in order to change the core of the system. Secondly, the system core is independent of other applications and interface. Initially, installing Linux was difficult because it was necessary to compile (put together) the entire operating system for a specific computer, which required knowledge of programming languages ​​and quick wits. The system also did not have a user-friendly graphical interface. Today there are many commercial operating system distributions, such as Red Hat or Mandrake, which include a graphical interface and sets of system utilities that are superior in capabilities to similar products for Windows. Among the advantages of Linux are high speed, stability and the ability to run without installation on a computer. Linux has some disadvantages, the main one being that it is difficult to configure. However, this will be eliminated over time. Now thousands of pages of help information on the Internet come to the aid of users of this operating system.

Lindows. This interesting operating system combines the advantages of Windows and Linux. Lindows can run applications written for both Windows and UNIX. The advantages of Lindows are obvious: you can download free software for Linux from the Internet (which is 90% of programs) and use it instead of expensive programs designed for Windows. It also has a drawback - low speed. Today, Lindows is installed only on some office computers, because its networking capabilities do not allow it to be used as a server operating system.

Thus, we install Windows 2012 Server OS on the server, and on user computers we give preference to the pre-installed operating system, thereby reducing the cost of purchasing the OS.

2.2 Equipment and software of the Internet cafe network RAID arrays

RAID (Redundant array of independent disks) is a data virtualization technology that combines multiple disks into a logical element for redundancy and increased performance.

To create a RAID array on a server, you must first of all have connected HDDs on the server itself. The motherboard installed in the server must either have an integrated RAID controller (built into the motherboard), or you will need to install a separate discrete RAID controller, which is usually installed in a special PCI-Express slot. Next, using the I/O device connected to the server, then through the RAID controller management interface, you create the desired level of the RAID array. A comparison of different RAID levels is shown in Table 1.

Table 1 - Comparison of RAID levels

	Number of disks	Effective capacity*	fault tolerance	Advantages	Flaws
				highest performance	very low reliability
	from 2, even			high performance and reliability
	from 3, odd			high data security and good performance	double cost of disk space
	from 4, even			highest performance and highest reliability	double cost of disk space
				economical, high reliability	performance is lower than RAID 0 and 1
	from 6, even			high reliability and performance	high cost and difficulty of maintenance
				cost-effective, high reliability, speed higher than RAID 5
				fast reconstructed data after a failure, cost-effective, high reliability, speed higher than RAID 5	performance is lower than RAID 0 and 1, the backup drive is idling and not checked
				economical, highest reliability	performance below RAID 5
	from 8, even			very high reliability	high cost and complexity of organization

N - number of disks in the array;

S is the volume of the smallest disk; ** Information will not be lost if disks within different mirrors fail.

*** Information will not be lost if the same number of disks in different stripes fail.

**** Information will not be lost if disks within the same mirror fail.

RAID level 10 or 01 provides the highest performance and high reliability. This array will be used on the server.

IEEE Standards

IEEE(Institute of Electrical and Electronic Engineers) - The Institute of Electrical and Electronics Engineers (IEEE) is an organization created in the USA in 1963. It is the developer of a number of standards for local computing systems, including cabling, physical topology and access methods to the data transmission medium. The most widely known series of standards are the 802 standards, for which the IEEE 802 Committee and its working groups and subcommittees are responsible.

· IEEE 802.1Q is a standard whose purpose is to establish a unified method for transmitting data over the network about the priority of a frame and its membership in a virtual LAN. It contains two packet marking specifications: the first (single-layer) defines the interaction of virtual networks over a Fast Ethernet backbone; the second (two-level) is related to packet marking in mixed backbones, including Token Ring and FDDI. The first specification is an enhanced switching technology supported by Cisco. The delay in the adoption of this standard is due to the need for detailed development of a more complex two-level specification.

· IEEE 802.1p - a standard that defines a method for transmitting data about the priority of network traffic. It is necessary to eliminate delays in the transmission of packets over the LAN. Delays that are unacceptable when transmitting voice and video can occur as a result of even short-term network overloads. This standard specifies an algorithm for changing the order of packets in queues, which ensures timely delivery of traffic that is sensitive to time delays.

· IEEE 802.2 is a link layer standard intended for use in conjunction with IEEE 802.3, 802.4 and 802.5 standards. Defines how a logical channel is controlled. Refers to the LLC sublayer of the data link layer.

IEEE 802.3

1. A standard that describes the characteristics of a cabling system for a LAN with a bus topology (10Base5), data transmission methods and a method for controlling access to the CSMA/CD transmission medium.

2. Working group (subcommittee) of the IEEE 802 Committee, which considers standards for Ethernet networks.

IEEE 802.4

1. A standard that describes the physical layer and access method with token passing in a LAN with a bus topology. Used in LANs that implement the Manufacturing Automation Protocol (MAP). A similar access method is used in the ARCnet network.

2. Working group (subcommittee) of the IEEE 802 Committee, considering standards for Token Bus networks.

IEEE 802.5

1. A standard describing the physical layer and token-passing access method in a LAN with a star topology. Used in Token Ring networks.

2. Working group (subcommittee) of the IEEE 802 Committee, considering standards for Token Ring networks.

· IEEE 802.6 is a standard that describes a protocol for metropolitan area networks (MANs). Uses fiber optic cable to transmit data at a maximum speed of 100 Mbit/s over an area of ​​up to 100 km 2.

· IEEE 802.11 - a specification for wireless radio communication links for computer networks - defines the 2.4 GHz frequency used by them, which is allocated in the USA for industry, science and medicine.

· IEEE 802.11a - specification for wireless radio communication lines for computer networks. Determines the use of the frequency range 5.15 - 5.35 GHz and data transfer rates (voice and video) up to 54 Mbit/s.

· IEEE 802.11b - specification for wireless radio communication lines for computer networks. Determines the use of the frequency 2.412 - 2.437 GHz and data transfer rates up to 11 Mbit/s.

network hardware

All network equipment is divided into active and passive.

Active network equipment processes and transmits packets and data on the network.

Passive network equipment only performs data transfer between network segments or network equipment.

A router (from the English router) is a specialized network computer that has two or more network interfaces and forwards data packets between different network segments. A router can connect heterogeneous networks of different architectures. To make decisions about packet forwarding, information about the network topology and certain rules set by the administrator are used.

The router used in this course project is a SafeStream gigabit VPN router with 2 ports TL-ER6020, with the following characteristics:

2 Gigabit WAN ports

· Supports multiple VPN protocols

Supports up to 50 IPsec VPN tunnels using a hardware VPN handler

· Ability to set bans on IM/P2P applications with one click of a button, which allows you to control the Internet use by your staff

· Supported speed 10/100/1000 Mbps.

Principle of operation

Typically, a router uses the destination address specified in the packet header and determines from the routing table the path along which the data should be sent. If there is no described route in the routing table for an address, the packet is discarded.

There are other ways to determine the forwarding route of packets using, for example, the source address, the upper layer protocols used, and other information contained in the network layer packet headers. Often, routers can translate the addresses of the sender and recipient, filter the transit data stream based on certain rules to limit access, encrypt/decrypt transmitted data, etc.

The routing table can be compiled in two ways:

1. Static routing - when entries in the table are entered and changed manually. This method requires administrator intervention every time changes occur in the network topology. On the other hand, it is the most stable and requires a minimum of router hardware resources to maintain the table.

2. Dynamic routing - when entries in the table are updated automatically using one or more routing protocols - RIP, OSPF, IGRP, EIGRP, IS-IS, BGP. In addition, the router builds a table of optimal paths to destination networks based on various criteria - the number of intermediate nodes, channel capacity, data transmission delay.

Network switch (English switch - switch) is a device designed to connect several nodes of a computer network within one or more network segments. The switch operates at the data link (second) layer of the OSI model. Switches have been developed using technology often seen as multiport bridges. Routers (OSI layer 3) are used to connect several networks based on a network.

Unlike a hub (OSI layer 1), which distributes traffic from one connected device to all others, a switch transmits data only directly to the recipient (the exception is broadcast traffic to all network nodes and traffic for devices for which the outgoing switch port is unknown). This improves network performance and security by freeing other network segments from having to (and being able to) process data that was not intended for them.

The switch used in this course project is a 16-port D-Link DGS-1016D/GE and a 24-port TL-SG1024, with the following characteristics:

· 24 ports 10/100/1000 Mbit/s (RJ45 connector);

· Supports the function of automatically detecting and remembering MAC addresses, supports auto-MDI/MDIX;

· Switching matrix up to 48 Gbit/s;

· Innovative energy-saving technology allows you to save up to 25% of consumed electricity.

· 16 ports 10/100/1000 Mbit/s (RJ45 connector);

32 Gb/s switch fabric

Non-blocking architecture

Operating principle of the switch

The switch stores in memory (the so-called associative memory) a switching table, which indicates the correspondence of the host MAC address to the switch port. When the switch is turned on, this table is empty and the switch is in learning mode. In this mode, data arriving on any port is transmitted to all other ports of the switch. In this case, the switch analyzes the frames (frames) and, having determined the MAC address of the sending host, enters it into the table for some time. Subsequently, if one of the switch ports receives a frame intended for a host whose MAC address is already in the table, then this frame will be transmitted only through the port specified in the table. If the destination host's MAC address is not associated with any port on the switch, then the frame will be sent to all ports except the port from which it was received. Over time, the switch builds a table for all active MAC addresses, resulting in localized traffic. It is worth noting the low latency (delay) and high forwarding speed on each interface port.

A firewall is a set of hardware and software in a computer network that controls and filters network packets passing through it in accordance with specified rules.

The main task of a firewall is to protect the network or its individual nodes from unauthorized persons. Also, firewalls are often called filters, since their main task is not to let through (filter) packets that do not meet the criteria defined in the configuration.

Some firewalls also allow address translation - the dynamic replacement of intranet (gray) addresses or ports with external ones used outside the local network - which can provide additional security.

The ZyWALL USG 1000 is used as a firewall in this course project, with the following characteristics:

5 universal WAN/LAN/DMZ GbE ports

· Kaspersky/ZyXEL streaming antivirus

· Intrusion detection and prevention

Blue Coat and Commtouch content filtering

· Commtouch spam filtering

2.3 Structure of the corporate computer network of the enterprise

Cable system

Twisted pair (Figure 6). Ideally, a transmission line consists of at least two conductors separated by a dielectric material and having a uniform gap along its entire length. A balanced voltage is applied to the two conductors, equal in amplitude and opposite in phase. Each conductor carries currents equal in magnitude and opposite in direction.

The currents produce concentric magnetic fields surrounding each of the conductors. The magnetic field strength increases in the space between the conductors and decreases in the space where concentric fields are located outside both conductors. The currents in each of the conductors are equal in magnitude and opposite in direction, which leads to a decrease in the total energy accumulated in the resulting magnetic field. Any change in currents generates a voltage on each conductor with a resulting electric field with a vector direction that limits the magnetic field and maintains a constant current.

Signal attenuation is the ratio, in decibels (dB), of the input signal power to the output signal power when the source and load impedances match the characteristic impedance of the cable. The input power value can be obtained by measuring the power when the load is directly connected to the source without passing the signal through the cable. In cases where the impedances at the termination locations are not perfectly matched, the ratio of input power to output power is called insertion loss or insertion attenuation.

Figure 6 - Twisted pair cable.

Digital computing systems, telephony and video broadcasting systems require new directions to improve transmission characteristics. The greater spectral width of an optical cable means increased channel capacity. Additionally, longer runs of cable require fewer repeaters because fiber optic cables have extremely low attenuation levels. This property is ideal for broadcast and telecommunications systems.

Compared to conventional coaxial cables of equal capacity, the smaller diameter and weight of fiber optic cables means comparatively easier installation, especially in crowded runs. 300 meters of single-fiber cable weighs about 2.5 kg. 300 meters of similar coaxial cable weighs 32 kg - approximately 13 times more.

Electronic eavesdropping methods rely on electromagnetic monitoring. Fiber optic systems are immune to this technique. To capture data, you need to physically connect to it, which reduces the signal level and increases the error rate - both phenomena are easily and quickly detected.

Figure 7 - Fiber optic cable.

This organization will use twisted pair cable of the 5th category.

SCS installation technology

When choosing network equipment, there are many factors to consider, including:

1. Level of equipment standardization and its compatibility with the most common software;

2. Speed ​​of information transfer and the possibility of its further increase;

3. Possible network topologies and their combinations (bus, passive star, passive tree);

4. Network exchange control method (CSMA/CD, full duplex or token method);

5. Permitted types of network cable, its maximum length, immunity to interference;

6. Cost and technical characteristics of specific hardware (network adapters, transceivers, repeaters, hubs, switches);

7. Document EIA/TIA-568A defines standards for cabling, cable types, network topologies, connectors and other equipment necessary to connect users to the network;

8. Work area. From the data socket (wall socket) to the user's workstation, including all connection sockets. The work area must have at least two data connectors: one for voice communication and the other for data transmission;

9. Horizontal calibration. Cables diverging from the telecommunications unit (cabinet, panel) to user workstations. This also includes switch crossover cables and patch cables on the node itself (in the cabinet). The maximum length of horizontal cables should not exceed 90 meters. Another 10 meters are allocated for switching and connecting cables at the node (in the cabinet) and in the work area;

10. Telecommunication cabinets and rooms (nodes). The telecommunications cabinet is built according to ANSI/EIA/TIA-569 standards. This is the place where all cables from user work areas converge. The telecommunications room (node) is a more complex structure. The main cables from telecommunication cabinets converge in it;

11. Mainline calibration. As a rule, it is carried out vertically between the floors of a building and is used to connect telecommunication cabinets and nodes;

12. Entry points. These are the points that connect the cables running from buildings to external service servers.

To lay network cables, the enterprise uses special hanging cable boxes and wall cables. In this case, the cables are reliably protected from mechanical influences.

To lay cables between rooms and/or between floors, holes are punched in walls or ceilings.

Cables should never support their own weight, as this may cause them to break over time. Therefore, at the enterprise they are suspended on steel cables.

Copper wire, particularly unshielded twisted pair, is the preferred medium for the horizontal cabling subsystem (which is planned to be implemented in the enterprise).

When choosing a cable, the following characteristics were taken into account: bandwidth, distance, physical security, electromagnetic immunity, cost.

In terms of labor intensity, installing unshielded twisted pair cable is not much different from thin coaxial cable; the rules for laying the cable are almost the same. Installation can be carried out either using stationary wiring or without it. For stationary wiring, a rigid single-core ("SOLID") cable of categories 3-4 is used, but better yet category 5 (so that in the future the transition to 100 Mbit/s does not require a cable revolution). Fixed wiring is done from wall sockets to the cable center. To install fixed wiring, no special tools are required; the wires are inserted into the blade contacts of the sockets and pressed with the caps included in the socket kit. To connect computers, RJ-45 plugs are installed at the ends of the cables (Figure 8).

Figure 8 - Cable connection.

RJ-45 connectors for single-core and multi-core cables differ in the shape of the contacts. Needle contacts are used for multi-core cable; the needles are stuck between the wire cores, ensuring a reliable connection. For a single-core cable, contacts are used that “embrace” the core on both sides. The use of connector types that do not match the cable may result in a short-lived connection.

Externally identical connectors from different manufacturers (and even from the same manufacturer with different markings) may differ in size, which is why they will not fit securely (with a click) into the sockets. You can check the connector for fixation only after crimping it.

The contacts of fixed wiring sockets and plugs of connection cables are connected “one-to-one” (straight cables). Cables connecting two hubs through regular ports (two computers in a point-to-point connection) are cross-connected.

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Design of a local computer network for an enterprise with a main office in the city center and two branches at a distance of no more than 1.5 km. Selection of network topology and main equipment. Software for client-server network interaction.

Moscow State Mining University

Department of Automated Control Systems

Course project

in the discipline "Computer networks and telecommunications"

on the topic: “Design of a local area network”

Completed:

Art. gr. AS-1-06

Yuryeva Ya.G.

Checked:

Prof., Doctor of Technical Sciences Shek V.M.

Moscow 2009

Introduction

1 Design task

2 Description of the local area network

3 Network topology

4 Local network diagram

5 OSI reference model

6 Justification for choosing a local network deployment technology

7 Network protocols

8 Hardware and software

9 Calculation of network characteristics

Bibliography

A local area network (LAN) is a communications system that connects computers and peripheral equipment in a limited area, usually no more than several buildings or one enterprise. Currently, a LAN has become an integral attribute in any computing systems with more than 1 computer.

The main advantages provided by a local network are the ability to collaborate and quickly exchange data, centralized data storage, shared access to shared resources such as printers, the Internet and others.

Another important function of a local network is the creation of fault-tolerant systems that continue to function (albeit not fully) if some of their elements fail. In a LAN, fault tolerance is ensured through redundancy and duplication; as well as flexibility in the operation of individual parts (computers) included in the network.

The ultimate goal of creating a local network in an enterprise or organization is to increase the efficiency of the computing system as a whole.

Building a reliable LAN that meets your performance requirements and has the lowest cost requires starting with a plan. In the plan, the network is divided into segments, and a suitable topology and hardware are selected.

The bus topology is often called a linear bus. This topology is one of the simplest and most widespread topologies. It uses a single cable, called a backbone or segment, along which all computers on the network are connected.

In a network with a “bus” topology (Fig. 1.), computers address data to a specific computer, transmitting it over a cable in the form of electrical signals.

Fig.1. Bus topology

Data in the form of electrical signals is transmitted to all computers on the network; however, only the one whose address matches the recipient address encrypted in these signals receives information. Moreover, at any given time, only one computer can transmit.

Since data is transmitted to the network by only one computer, its performance depends on the number of computers connected to the bus. The more there are, i.e. The more computers waiting to transfer data, the slower the network.

However, it is impossible to derive a direct relationship between network bandwidth and the number of computers in it. Since, in addition to the number of computers, network performance is influenced by many factors, including:

· hardware characteristics of computers on the network;

· the frequency with which computers transmit data;

· type of running network applications;

· type of network cable;

· distance between computers on the network.

The bus is a passive topology. This means that computers only “listen” to data transmitted over the network, but do not move it from sender to recipient. Therefore, if one of the computers fails, it will not affect the operation of the others. In active topologies, computers regenerate signals and transmit them across the network.

Signal reflection

Data, or electrical signals, travel throughout the network - from one end of the cable to the other. If no special action is taken, the signal reaching the end of the cable will be reflected and will not allow other computers to transmit. Therefore, after the data reaches the destination, the electrical signals must be extinguished.

Terminator

To prevent electrical signals from being reflected, terminators are installed at each end of the cable to absorb these signals. All ends of the network cable must be connected to something, such as a computer or a barrel connector - to increase the cable length. A terminator must be connected to any free - unconnected - end of the cable to prevent electrical signals from being reflected.

A local area network (LAN, LAN - Local Area Network) is a set of hardware and software that allows you to combine computers into a single distributed system for processing and storing information. All services and additional devices are also important, but they will not work in the absence of a properly designed and installed local network. Hardware includes computers with network adapters installed on them, repeaters, hubs, switches, bridges, routers, etc., connected to each other by network cables. Software includes network operating systems and information transfer protocols. The distance between computers connected in a LAN usually does not exceed several kilometers, which is due to the attenuation of the electrical signal in the cables. The technology of virtual private networks (VPN - Virtual Private Network) allows, via the Internet or telephone lines, to combine several LANs separated by thousands of kilometers into a single LAN.

Basic capabilities of local (computer) networks:

• File transfer. Firstly, paper and printer ink are saved. Secondly, the electrical signal travels along the cable from department to department much faster than any employee with a document.
• Sharing data files and programs. Now there is no need to duplicate data on each computer. If accounting data is simultaneously needed by management and the economic planning department, there is no need to take up time and nerves from the accountant, distracting him from cost calculation every three seconds. The network allows users to work with the program simultaneously and see the data entered by each other.
• Sharing printers and other equipment. Significant savings are made on the purchase and repair of equipment, because There is no need to install a printer on each computer; just install a network printer.
• Email and instant messaging systems. In addition to saving paper and speedy delivery, problems like “I was there, but just left. Come back (wait) in half an hour”, “They didn’t deliver it to me” are eliminated. Whenever a busy comrade returns, the letter will be waiting for him.
• Coordination of teamwork. When solving problems together, everyone can remain at their workplace, but work “as a team.” For the project manager, the task of monitoring and coordinating actions is greatly simplified, because the network creates a single, easily observable virtual space with high speed of interaction between geographically dispersed participants.
• Streamlining office work, controlling access to information, protecting information: The fewer potential opportunities to lose (forget, put in the wrong folder) a document, the fewer such cases there will be. In any case, it is much easier to find a document on the server (automatic search, the author of the document is always known) than in a pile of papers on the table. The network also allows you to implement a unified security policy at the enterprise, relying less on the consciousness of employees: you can always clearly define access rights to documents and log all employee actions.

Recently, the so-called wireless networks based on the transmission of information over secure radio channels. This kind of equipment is used where it is not possible to lay a cable, for connecting separate buildings, for connecting from mobile and pocket computers, etc. Mixed systems (simultaneous use of cable and wireless technologies on a LAN) are the most promising option for building enterprise local networks.

Local area network is a concept that is familiar to many firsthand. Almost every enterprise uses this technology, so it can be said that every person has come across it in one way or another. Local networks have significantly accelerated production processes, thereby giving a sharp boost to their further use throughout the globe. All this allows us to predict the further growth and development of such a data transmission system, up to the introduction of a LAN in every, even the smallest enterprise.

The concept of a local network

A local area network is a number of computers connected to each other by special equipment that allows for the full exchange of information between them. An important feature of this type of data transmission is the relatively small area where communication nodes, that is, the computers themselves, are located.

Local networks not only greatly facilitate interaction between users, but also perform some other functions:

• Simplify work with documentation. Employees can edit and view files at their workplace. At the same time, there is no need for collective meetings and meetings, which saves valuable time.
• They allow you to work on documents together with colleagues, when everyone is at their own computer.
• They allow access to applications installed on the server, which allows you to save free space on the installed hard drive.
• Save hard drive space by allowing you to save documents on your host computer.

Types of networks

A local area network can be represented by two models: a peer-to-peer network and a hierarchical one. They differ in the ways communication nodes interact.

A peer-to-peer network is based on the equality of all machines, and data is distributed between each of them. Essentially, a user of one computer can access the resources and information of another. The efficiency of the peer-to-peer model directly depends on the number of worker nodes, and its level of security is unsatisfactory, which, coupled with a rather complex management process, makes such networks not very reliable and convenient.

The hierarchical model includes one (or more) main server, where all data is stored and processed, and several client nodes. This type of network is used much more often than the first, having the advantage of speed, reliability and security. However, the speed of such a LAN largely depends on the server, which under certain conditions can be considered a disadvantage.

Drawing up technical requirements

Designing a local area network is a rather complex process. It begins with the development of a technical specification, which should be carefully considered, since shortcomings in it threaten subsequent difficulties in building a network and additional financial costs. Primary design can be done using special configurators that will allow you to select the optimal network equipment. Such programs are especially convenient in that you can correct various values ​​and parameters directly during operation, as well as generate a report at the end of the process. Only after these steps can you proceed to the next stage.

Schematic design

This stage consists of collecting data about the enterprise where it is planned to install a local area network, and analyzing the information received. The quantity is determined:

• Users.
• Workstations.
• Server rooms.
• Connection ports.

An important point is the availability of data on the routes for laying highways and the planning of a specific topology. In general, it is necessary to adhere to a number of requirements imposed by the IEEE 802.3 standard. However, despite these rules, sometimes it may be necessary to make calculations of signal propagation delays or consult with network equipment manufacturers.

Basic LAN characteristics

When choosing a method for placing communication nodes, you must remember the basic requirements for local networks:

• Performance, which combines several concepts: throughput, response time, transmission delay.
• Compatibility, i.e. ability to connect various local area network equipment and software.
• Safety, reliability, i.e. capabilities to prevent unauthorized access and complete data protection.
• Scalability - the ability to increase the number of workstations without degrading network performance.
• Manageability - the ability to control the main elements of the network, prevent and eliminate problems.
• Network transparency, which consists of presenting a single computing device to users.

Basic local area network topologies: advantages and disadvantages

The topology of a network represents its physical layout, significantly affecting its basic characteristics. In modern enterprises, three types of topologies are mainly used: “Star”, “Bus” and “Ring”.

The “Star” topology is the most common and has many advantages over others. This installation method is highly reliable; If any computer fails (except the server), this will not affect the operation of the others.

The “Bus” topology is a single backbone cable with connected computers. Such an organization of a local area network saves money, but is not suitable for connecting a large number of computers.

The “Ring” topology is characterized by low reliability due to the special arrangement of nodes - each of them is connected to two others using network cards. The failure of one computer leads to the shutdown of the entire network, so this type of topology is used less and less.

Detailed network design

An enterprise local area network also includes various technologies, equipment and cables. Therefore, the next step will be the selection of all these elements. Making a decision in favor of one or another software or hardware is determined by the purpose of creating the network, the number of users, the list of programs used, the size of the network, and its location. Currently, fiber optic highways are most often used, which are distinguished by their high reliability, speed and availability.

About cable types

Cables are used in networks to transmit signals between workstations; each of them has its own characteristics, which must be taken into account when designing a LAN.

• A twisted pair consists of several pairs of conductors covered with insulation and twisted together. Low price and ease of installation are beneficial advantages, which makes this cable the most popular for installing local networks.
• A coaxial cable consists of two conductors inserted one inside the other. A local area network using coax is no longer so common - it was replaced by twisted pair, but it is still found in some places.
• Optical fiber is a glass thread that can carry light by reflecting it off walls. A cable made from this material transmits data over long distances and is fast compared to twisted pair and coaxial cables, but it is not cheap.

Necessary equipment

Network equipment of local area networks includes many elements, the most commonly used of which are:

• Hub or hub. It connects a number of devices into one segment using a cable.
• Switch. Uses special processors for each port, processing packets separately from other ports, due to which they have high performance.
• Router. This is a device that makes decisions about sending packets based on data about routing tables and some rules.
• Modem. Widely used in communication systems, providing contact with other workstations via a cable or telephone network.

End network equipment

The local area network hardware necessarily includes server and client parts.

A server is a powerful computer with high network significance. Its functions include storing information, databases, serving users and processing program codes. The servers are located in special rooms with a controlled constant air temperature - server rooms, and their housing is equipped with additional protection from dust, accidental shutdown, as well as a powerful cooling system. As a rule, only system administrators or company managers have access to the server.

A workstation is a regular computer connected to a network, that is, it is any computer that requests services from the main server. To ensure communication at such nodes, a modem and a network card are used. Since workstations usually use server resources, the client part is equipped with weak memory sticks and small hard drives.

Software

Local area network equipment will not be able to fully perform its functions without suitable software. The software part includes:

• Network operating systems on servers that form the basis of any network. It is the OS that controls access to all network resources, coordinates packet routing, and resolves device conflicts. Such systems have built-in support for the TCP/IP, NetBEUI, IPX/SPX protocols.
• Autonomous operating systems that manage the client side. They are common operating systems, for example, Windows XP, Windows 7.
• Network services and applications. These software elements allow you to perform various actions: viewing remote documentation, printing on a network printer, sending email messages. Traditional services HTTP, POP-3, SMTP, FTP and Telnet are the basis of this category and are implemented using software.

Nuances of designing local networks

Designing a local area network requires a long and leisurely analysis, as well as taking into account all the subtleties. It is important to provide for the possibility of enterprise growth, which will entail an increase in the scale of the local network. The project must be drawn up in such a way that the LAN is ready at any time to connect a new workstation or other device, as well as upgrade any of its nodes and components.

Security issues are no less important. The cables used to build the network must be reliably protected from unauthorized access, and the lines must be located away from potentially dangerous places where they can be damaged - accidentally or intentionally. LAN components located outside the premises must be grounded and securely secured.

Developing a local area network is a fairly labor-intensive process, but with the right approach and due responsibility, the LAN will operate reliably and stably, ensuring uninterrupted user experience.