Structured cabling system (SCS) is the basis of any information structure enterprises and allows you to bring together many information services having various purpose(telephone and local computer networks, networks of security systems and control and access control systems,video surveillance and much more) into one single system.
What is the SCS?
SCS is a cable hierarchical system of a building or a group of buildings and consists of structural subsystems. The SCS includes a set of optical and copper cables, patch cords, cross panels, modular jacks, cable connectors, accessories and information outlets. All these elements are integrated into a single system and operated in accordance with certain standards and rules.
Structured
Any combination or set of dependent and related constituent parts is called a structure. And the term "structured" means:
- - Ability to maintain the system various applications telecommunications, such as data, voice and video transmission;
- - Ability to apply different components and products from different manufacturers;
- - Ability to implement multimedia environments that use multiple various types transmission media such as STP, UTP, coaxial cable and optical fiber.
The structure of the entire cabling system is determined by the information technology infrastructure (IT = Information Technology). The content of a particular cable system project depends on it in accordance with the needs end user, regardless of the active equipment that can subsequently be used.
cable system
A system whose elements are components and cables, and which are connected to a cable, is called a cable system. All passive switching equipment of cable components serves to connect or physically terminate (terminate) the cable:
- Couplings and spices;
- Switching (“patch panels”) and cross panels in telecommunication premises;
- Telecommunication sockets at workplaces
SCS standards and categories
On the this moment there are 3 main standards in the field of SCS:
- American standard - EIA / TIA-568С Commercial Building Telecommunications Wiring Standard
- The European standard is CENELEC EN 50173 Information Technology. Generic cabling systems
- The international standard is ISO/IEC IS 11801-2002 Information Technology. Generic cabling for customer premises
The EIA/TIA-568C standard for cable lines and components includes the following categories
- Category 3, allowing signal transmission up to 16 MHz
- Category 5e up to 100 MHz bandwidth
- Category 6A, up to 500 MHz bandwidth
For ISO 11801-2002 and EN 50173 the following classes are defined with individual parameters bandwidth for cable lines:
- C, up to 16 MHz
- D, up to 100 MHz
- E, up to 250 MHz
- E(A), up to 500 MHz
- F(A), up to 600 MHz
The technical level of the current standards of the element base allows and guarantees the operability of the installed cable system for more than 10 years.
Any SCS project must meet the requirements of the standards
In general, the project on the SCS must meet the requirements (not all at the same time) of the standards of national or local regulations (EIA / TIA-568C and / or ISO / IEC 11801-2002, EIA / TIA-569A, EIA / TIA-606A).
Starting from 01.01.2010, on the territory Russian Federation, the following GOSTs apply:
- 53246-2008 - defines the general requirement for all major SCS nodes
- 53245-2008 - defines the test method
Both of these standards have errors and typos, so use them carefully.
Applications supported by the cable system must be approved by documents from any of these organizations:
- International Organization for Standardization (ISO),
- Asynchronous Transfer Mode (ATM) Forum,
- Institute of Electronic and Electrical Engineers (IEEE),
- American National Standards Institute (ANSI).
Cabling infrastructure must meet the requirements of ANSI TIA/EIA-568C and ANSI TIA/EIA-569.
A properly built and designed local network is not only a guarantee reliable operation office, but also a great investment. A modern structured cabling network (SCN) allows you to easily connect a variety of equipment to it, is easily modified and expanded at very low operating costs. Properly selected active network components (routers, switches, firewalls, access points, etc.) are able to do the job computer network the most reliable and information-safe.
Our company has been designing and installing local networks for more than 8 years, and the accumulated experience, coupled with close cooperation with leading manufacturers of SCS and computer equipment, allows us to offer our customers great solutions on the organization of computer networks. Today we offer:
- Design, installation and maintenance of SCS of the 5th and 6th categories. – taking into account in detail the possibilities and needs of the customer, the specifics of the premises and the architecture of buildings, we are ready to build the optimal SCS for your needs.
- The whole complex of low-current systems united by a single structured cable network - television, telephony, video surveillance, monitoring and dispatching systems, video surveillance and security.
- At the request of the customer, SCS can be made in closed or open wiring using cable systems from leading manufacturers DKS, Legran, NEXANS
- Supply, placement and configuration of the active network equipment- on time, with a maximum guarantee and on a turnkey basis. All equipment supplied by us is presetting and testing at the technical sites of the company. This approach allows us to shorten the time of installation and configuration of equipment at the customer's site and at the same time gives us and our customers confidence in the quality and reliability of the supplied systems.
- Construction of territorial networks - using ADSL technologies over a copper wire or GePON over an optical channel. The optimality of this approach for organizing networks of an office building or a cottage settlement is confirmed by domestic and foreign practice.
- Modern systems for solving typical office network tasks:
- Telephony for the office - both based on the classical approach, and including IP telephony.
- Ensuring the functioning of working groups - based on thin clients or NComputing terminal solutions
- Information storage and backup systems - network disk arrays NAS capacity up to 18TB
- Consolidation of geographically dispersed networks into a single system public networks based on VPN or using special crypto-equipment or with the allocation of additional communication channels.
- Connecting remote subscribers and home workers -
- Unique projects - to fully meet the needs of the customer, we are ready to work out and implement projects of almost any complexity. To solve specific problems, we have sufficient experience, the necessary personnel and resources. If necessary, we have the opportunity to involve leading industry experts and employees of equipment manufacturers.
In our work, we primarily focus on long-term cooperation with our customers, and the systems supplied by us have a full warranty and post-warranty service.
Data networks are one of the most important places in IT infrastructure. is designed taking into account the wishes of the customer, the necessary requirements for data transfer speed and operating conditions. Today, SCS is a necessary attribute of every office, residential, public and industrial building and ensures operability by linking various IT equipment into a single whole: server, PC, office equipment, ip telephony, etc.is the basis of the information structure of any enterprise. The whole variety of information services of various types and purposes, various peripherals, as well as workstations, SCS allows you to combine into one system. Systems such as: local and telephone networks, security and fire alarms, video surveillance systems, access control and management are an integral part of any modern organization. Competent and high-quality SCS allows you to structure all these services, which in turn increases the efficiency of the company.
SCS provides its subscribers with the following information services:
SCS consists of the following subsystems:
Basic principles of SCS construction:
Performance
SCS equipment is selected based on the planned volumes of processed traffic, as well as on the requirements for equipment functions and protocols used.Reliability and Availability
The mode of operation of the SCS is around the clock, 7 days a week, 365 days a year. In the event of failures, the SCS has the ability to automatically reconfigure in order to maintain operability and minimize downtime.Scalability
SCS provides for the possibility of expansion, i.e. its topology and equipment provide the ability to increase the number of connected points and increase the amount of traffic. All SCS equipment is selected with a reserve, both in terms of performance and the possibility of installing additional modules and expanding functionality.Efficiency
During the SCS design process, optimization is carried out in order to use resources more efficiently (the amount of memory, processor performance, throughput data channels). Effective use resources SCS reduces the total cost of ownership of the system.Security
The SCS takes into account the requirements for the organization of security and protection against unauthorized access (NSD). All devices included in the SCS are protected by a password system that has several levels. Authentication of access to equipment can be performed using software(Software) authentication that provide password encryption. Remote access to devices can be carried out using protocols that provide a secure control session.Unification and standardization
When creating SCS as an active network equipment, it is proposed to use equipment from one manufacturer. The equipment has a single for all devices operating system(OS).The IP protocol is used to ensure interaction between different SCS subsystems.
SCS standards:
1) American EIA/TIA-568B Commercial Building Telecommunications Wiring Standard2) international standard ISO/IEC IS 11801 Information Technology. Generic cabling for customer premises
3) European standard CENELEC EN 50173 Information Technology. Generic cabling systems
Among the implemented projects is SCS MGUP "Mosvodokanal", which included such works as: design of SCS, installation and crossing of racks, laying optical lines communications (FOCL).
We work with the whole range of fiber optic products (FOCL), copper pairs, server cabinets, patch panels, sockets, etc. Our company has modern equipment and software for the design and installation of SCS. Upon delivery of the project, a full report on testing of all laid communication lines is attached. The implementation of SCS is carried out using network active and passive equipment from leading manufacturers, such as Cisco, Hewlett-Packard, 3COM, etc.
Design of SCS (structured cabling system)
The design department of the GREEN EFFECT company provides a full range of services for SCS design.At the first stage of SCS designing, an inspection of the object, negotiations with the customer, identification of tasks and requirements for SCS are carried out.
Based on the results of research and analysis of the initial data, an optimal project for constructing a structured cabling system is developed, which includes all the wishes and requirements of the customer. The SCS project includes: detailed plans location of system elements; fundamental and block diagrams connections, cable laying routes, cable magazine. A specification of equipment and materials, an estimate for mounting SCS and statements of work performed are also compiled.
SCS design is carried out in accordance with Decree of the Government of the Russian Federation of February 16, 2008 No. 87 "On the composition of sections of project documentation and requirements for their content", regional building codes and requirements of the technical assignment.
When designing SCS, the requirements of existing legislation and regulatory documents on ecology, labor protection and fire safety are taken into account.
Pre-project survey
The purpose of the pre-project survey is to determine a set of measures and develop technical proposals taking into account the formed standard solutions. Based on the results of the survey, our design engineers will help the Customer develop a competent technical task (TOR) for the design of the SCS.Terms of Reference (TOR) SCS
Customer requirements form the basis terms of reference (TOR) SCS and are the primary document from which work begins on the creation of a structured cabling system. In addition to technical requirements, at the first stages of work on the design of SCS, data obtained during the pre-project survey is used as initial information. Any design begins with a correctly written technical task approved by the customer. A well-written TOR determines the timing of design and the choice of the necessary equipment for the construction of SCS, described in the TOR.The composition of the design documentation of the SCS is regulated by the Decree of the Government of the Russian Federation "On the composition of the sections of the design documentation and the requirements for their content" dated February 16, 2008 No. 87.
SCS project documentation (stage "P")
A well-designed SCS concept and terms of reference provide grounds for creating a draft SCS plan - a single set of solutions designed to provide preset mode operation of the SCS. The preliminary design defines the optimal structure of the SCS and the route for laying cable wiring, the location and composition of the elements of the telecommunications infrastructure, the idea of the project budget, as well as a number of other parameters that will facilitate the choice of specific solutions.SCS project documentation is text and graphic materials that define space-planning, design and technical solutions for the construction or reconstruction (modernization) of SCS.
The basis for the development of the SCS project is the architectural, construction, technological and engineering parts of the Building Design. The SCS project is focused on the use of the most efficient and well-proven equipment and components. Good design is high speed performance of construction works and maintenance of SCS. Error-free project calculation - minimization of equipment costs.
Working documentation of SCS (stage "P")
At the next stage, the working documentation of the SCS is developed, which is used at the construction stage. It is at this stage that the resource intensity of the process, the volume of construction and installation work, the amount of equipment and materials needed, and hence the final budget of the SCS project, are determined.The working documentation of the SCS is developed after the approval of the previous design stage. The purpose of the work at the "P" stage is to prepare accurate drawings, diagrams and tables that will guide the installers when carrying out work on the creation of the SCS. Working documentation provides a detailed binding of the components of all systems to the object. Working documentation of the SCS contains drawings, tables of connections and connections, plans for the location of equipment and wiring, and other documents.
Estimated documentation SCS ("SD")
The development of estimate documentation is final stage design of a structured cabling system and determines the total cost of equipment, construction, installation and commissioning.Installation of SCS
In accordance with the SCS project approved by the Customer and the purchase of the necessary equipment, the following is carried out:GREEN EFFECT specialists provide a full range of SCS installation services.
The accumulated experience in this area allows us to install and connect the SCS in the shortest possible time, in strict accordance with the project and the proper quality of work.
SCS setup
Upon completion of installation, the SCS is subjected to comprehensive testing and settings in order to check the system performance and identify defects. The results of testing and tuning with explanations of parameter values and analysis of the quality of the structured cabling system are provided to the customer (an example of a test report in the figure). After the completion of all work and the transfer of documentation to the customer, representatives of the contractor and the customer inspect the facility. In case of fulfillment of all necessary requirements and tasks, as well as compliance with the terms of reference, the object is put into operation.
Maintenance of SCS (structured cabling system)
Maintenance of structured cabling system (TO SCS) carried out to ensure the smooth operation unified system IT equipment of the company and constant access of personnel to various information services.Maintenance of the SCS is implemented by diagnosing the state of all sections of the SCS, carrying out measurements in cross cabinets, detecting and eliminating damage to the SCS elements.
SCS maintenance includes:
Volume of work Maintenance SCS depend on the operating conditions and the composition of the equipment.
Preventive maintenance works of SCS:
Diagnostics of the SCS ports consists in measuring the parameters of the SCS ports for compliance with the categorization parameters using the appropriate certified instrumentation with the issuance of reports on all measured parameters in the entire frequency range. Non-compliance of SCS ports with the requirements of categorization is determined by the results of port diagnostics.
Restoration works of technical maintenance of SCS:
The faults identified as a result of preventive maintenance are eliminated by the Contractor as part of the maintenance of the SCS. Depending on the nature of the fault, a decision is made to withdraw the faulty equipment from use and include it in the SCS current repair plan, or to eliminate the defect on the spot. Faults that require elimination additional work and material resources, to be eliminated after the compilation of the defective statement. Identified violations of the SCS operating conditions are reported to the Customer's representatives.
The schedule for the maintenance of the SCS is developed and approved by the Customer. Based on the results of the work, the contractor submits a report, which includes:
The current categories of copper unshielded twisted pair cabling, defined by the international standard ISO / IEC 11801 and the American standard ANSI / EIA / TIA 568-B are categories 3, 5 and 5e, 6, 6a, categories 7, 7a (ISO 11801 international standard), and since June 2016 cat.8 ( cable standard ANSI/TIA-568-C.2-1). Some networks still use legacy Category 1 and Category 2 cables.
Category3 represents 4-pair cable for building telephone and local networks 10BASE-T and token ring, supports data transfer rates up to 10 Mbps or 100 Mbps using 100BASE-T4 technology at a distance of no more than 100 meters, meets the requirements of the IEEE 802.3 standard.
Category 4 twisted pair cable consists of 4 twisted pairs, used in token ring, 10BASE-T, 100BASE-T4 networks, data transfer rate does not exceed 16 Mbps over one pair, is not used now.
On cable twisted pair categories 6 it is possible to organize transport over the network at a speed of 10 Gigabit / s at a distance of 30-55 meters.
SCS category6A organizes data transmission over a network at a speed of 10 Gigabit / s, using 10 Gigabit Ethernet (10GbE) technology, at a distance of up to 100 meters. Cat. 6a supports the new wireless Wi-Fi standard - IEEE 802.11ac. This standard allows you to increase the data transfer rate up to one Gb / s.
Twisted pair 8th cat. differs from the TIA 568-C.2 standard in shorter length and fewer connection points. Category 8 channel configuration includes two modular jacks. Maximum length fixed horizontal cable - 24 m. The total length of modular equipment cords 24 AWG - a maximum of 6 m.
In such channels, interconnections are used to connect active equipment, at the ends of which only one unit of switching equipment is involved: a patch panel port or sockets.
Twisted pair 8th cat is used to organize the physical infrastructure of the data center with the topology "top of rack" (each cabinet is installed network switch) and “end of row” (the end cabinet in each row plays the role of a distributor and is equipped with patch panels with horizontal cable pulling to the rest of the cabinets in this row).
The ANSI/TIA-568-C.2-1 cable standard for Category 8 (Cat 8), effective since 2016, specifies requirements for a twisted-pair channel up to 30 m. 45.
Accounting for PoE needs in Category 8 copper SCS
Twisted pair cables cat. 8, using large-section conductors, is characterized by the ability to transmit currents much larger than in other systems, while due to the shielding, such cables heat up less - more precisely, they remove heat more efficiently. Other things being equal, such cables can be assembled into bundles bigger size than the previous categories, and for PoE applications this is an important consideration.There are two more Cat. 8.1 and cat. 8.2.
- Twisted pair cat. 8.2. fully compatible with cat.7A cable, provides data transfer rates up to 40 Gbps using standard 8P8C or GG45/ARJ45 and TERA connectors. This category of cable has an overall shield and shields around each F/FTP or S/FTP pair. Is under development.
Twisted pair cat. 8.1 Fully compatible with Cat.6A cable, provides data transfer rates up to 40Gbps when using standard 8P8C connectors. This category of cable has either an overall shield or shields around each F/UTP or U/FTP pair. Is under development.
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Frequency range |
Applications |
Year of adoption of the standard |
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1 pair, used only for voice/data transmission via modem (not suitable for modern systems)/ |
Obsolete Standard |
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2 pairs, 4 Mbps in Token networks ring and Arcnet (not suitable for modern systems). Sometimes found in telephone networks. |
Obsolete Standard |
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10BASE-T, 100BASE-T4 Ethernet |
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Token Ring 16Mbps |
1993, obsolete standard |
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100Base-TX (Fast Ethernet) |
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Fast Ethernet (100BASE-TX), Gigabit Ethernet (1000BASE-T) |
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Gigabit Ethernet 2.5 Gbps |
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10 Gigabit Ethernet (10GBASE-T) |
specification for |
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10 Gigabit Ethernet (10GBASE-T) |
specification for given type cable approved only by the international standard ISO 11801 |
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1600 - 2000 MHz |
40GBase-T supporting IEEE 802.3bq |
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1600 - 2000 MHz |
in developing |
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1600 - 2000 MHz |
100 Gigabit Ethernet (40GBASE-T) |
in developing |
Development of SCS standards
2010ANSI/TIA-1179 Healthcare Telecommunications Infrastructure Standard. The standard recommends the use of systems of the highest category to ensure the highest possible service life and reduce the costs associated with replacing obsolete cables. For new installations, these are category 6a cables and connectors.
ANSI/TIA-942-A is the telecommunications infrastructure standard for data centers. TIA-942-A includes TIA-942 and two addenda that recognize coaxial cables and recommend category 6a as the minimum acceptable for data centers.
ANSI/TIA-4966 Telecommunications Infrastructure Standard for Educational Institutions. Cat. 5e is recognized, cat. 6a recommended for expansion functionality wired and wireless communication networks.
Correspondence of cable and connector categories to application classes
The ISO/IEC 11801 and TIA/EIA-568-B standards specify cables and connectors by category. Categories are defined maximum frequency signal that the corresponding connectors and cables are designed for. Higher category cables and connectors support all applications that are designed to work on lower category cables. The main differences between communication lines of various categories
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Parameter |
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Frequency range, MHz |
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Attenuation, dB |
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Return loss, dB |
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Propagation delay, ns |
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The practice of applying standards for cabling systems
Modern cable systems are built taking into account rigidly determined international industry standards. In addition, the Russian Federation has its own SCS standards. Standards for the development of SCS are increasingly used in modern networks, since they spell out the basic requirements for the creation of highly reliable communication networks.To ensure the guaranteed quality of building cable systems, it is especially important for contractor companies to strictly comply with design standards, procedures that involve the installation of SCS, processes for preparing documentation, administering and operating systems. In connection with these priorities, SCS standards are conditionally divided into requirements for design, installation and administration.
Design standards prescribe the conditions of the transmission medium and the parameters of the connectors used, as well as the quality of the line and channel, the permissible cable lengths, the methods of connecting conductors, the topology and functional elements structured cabling system. A special group includes industrial standards for the construction of SCS, which define the rules for the design and operation of cable networks in various sectors of the economy.
Traditionally, the main processes for the development of international industry standards are carried out by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). The current reference document for structured cabling is ANSI/TIA/EIA-568-Ay, the commercial building telecommunications cabling standard.
The European Committee for Electrotechnical Standardization (CENELEC) operates in conjunction with the International Organization for Standardization. CENELEC countries adopt European design standards as national requirements without any amendment.
In the industrial sector of the economy, there is a need for specialized interfaces for managing and controlling structured networks. Therefore, to develop industrial SCS interfaces, the international association TIA (Telecommunications Industry Association) and the IEC (International Electrotechnical Commission) committee joined together several years ago. The purpose of the joint activity of this group is to develop standards for the creation and use of telecommunication infrastructures for industrial buildings, complexes and campuses, commercial buildings or structures created according to a unique project.
However, it should be pointed out that the adopted regulatory documents are always observed during the construction of SCS, adjusted for each specific facility.
For instance, international standards(ISO) allow an increase in the length of lines over 90 meters and determine the permissible length of electrically conductive channels in the range from 100 to 3000 meters. But in practice, restrictions on the length of highways are conditional. Depending on the type of object, its location and parameters.
SCS- structured cable network. Or, roughly speaking, "sockets in the wall." The most expensive thing in SCS is not sockets, but huge kilometers of wires connecting sockets with server and switching rooms.
The layer of concepts that are hidden behind the SCS is very extensive. They have their own professionals who know when to organize switching on floors, how to properly guide a bundle of fibers between floors, etc. There are also marketers whose task is to convince you that you need to do exactly this, $Xk more in the estimate, and not the way you wanted.
The area of SCS design itself is closer to construction (engineering) work than to the area of system administration.
But sometimes in the life of a system administrator a situation arises when it depends on him what the SCS will be in the building (floor, room) of the company. In the worst case, the system administrator drags it himself, at best, this task is outsourced (more precisely, to contractors). But what kind of SCS will be, usually two or three people decide. At the same time, the remaining two determine only the budget, and only a system administrator can fight for quality. [on the other side is a representative of the contractor, who drags the blanket in his direction, and although he may seem to the system administrator as an ally in the battle for the quality of the SCS, in fact, he just wants more expensive, and should be treated with caution].
Here I am writing exactly the point of view of the administrator, as the "end user" of the SCS. If I lied somewhere, or forgot to write about something important - say, I'll correct it.
So SCS.
Owner's (director's) point of view
Need wires and sockets. The cheaper the better. The administrator once said that computer computers can be branched locally, so you can put them smaller, because it's expensive. By the way, there are a bunch of people sitting there, one socket is enough for them.Contractor's point of view
The client needs to sell as much as possible. At most, this is a full-fledged SCS with switching rooms on the floors, interfloor optics ... What? Does he want cheaper? Well, figs with him, let him do what he wants.What do YOU need from SCS?
Speed
Write down for yourself the minimum that you need. Despite the stories of marketers, 10 megabits is enough for most modern applications. Rare Application you need 100 megabits (mainly due to the transfer of a large amount of data). If the application needs gigabit, then you may have made a mistake with the place to install it (maybe it's better to be closer to the servers?). Write down everything that is usually done on a computer. It turns out that most of these tasks are absolutely not demanding on speed. If you have not found such applications, then the requirements of category 5e, and not 6, are quite boldly written in the TOR, as you may be persuaded.Telephony
Some companies use IP phones, they are not interested in this issue. If your IP ends near the PBX or old telephony is used, then telephone sockets needed. The question is how to make them?Options:
- On the same wire with ethernet
- Multiple phone pairs on one wire
- Separately, a separate wire for each outlet.
The first option (ethernet + telephone), formally, is acceptable (there may be two applications in one cable), but in my practice I met a cable in which packets began to be lost at the time of the call (call). The main advantage of this solution is saving on wires. The main disadvantage is the need to breed everything. It is not comfortable.
The second option (ethernet separately, telephony with 4 pairs per wire) is slightly better, but complicated by the problem of wiring in the wall from socket to socket. If your contractor is ready to do it without additional. payment - this may be an option. The disadvantage is the non-universality of the SCS (more on this below), the plus is significant savings on the cable (1 cable instead of 4).
The third option (each outlet has a separate cable) is the most interesting and most expensive. You have a strictly set of wires between the server (switching) and the socket. What to let through it (ethernet or telephony) - you decide. The peak of versatility is RJ45 sockets for both ethernet and telephony (telephone RJ11 is completely included in RJ45).
The third option is very important in terms of universality. Do you need two phones? (fax + telephone) - please, here are two sockets, you can use them. Do you need another print server instead of a phone? Please.
This option is the easiest to connect (1 wire - 1 application), the most easily debugged and reliable. And the most costly.
If you have a large building, then with 500 phone sockets, you will lose about 12 kilometers of cable (you can calculate the price yourself) compared to the first option and about 18 km of cable compared to the second.
How many outlets
The main stumbling block. Each outlet is MONEY. Each outlet without use is money down the drain. Usually, the directorate looks at the seating plan for employees, determines the number of sockets, allows, well, at most, +2 in reserve - and that's it. And then it turns out that there are only 3 pairs of sockets in a room for 10 people. Because earlier it was thought that it would be a presentation room, but now it is a room for accountants. Oh yes, we need two more network printer, here to that wall, and to this one. No outlets? Who cares?The solution to the problem is to place outlets not by the number of employees, but by the MAXIMUM POSSIBLE number of jobs. Those. by room size.
It turns out EXPENSIVE. Approximately 1.5-4 times more expensive than if done "for working". But at the same time, the SCS becomes universal, i.e. suitable for any number of employees in any location.
An argument for the authorities: if we make SCS according to the number of jobs, then when changing the profile of the business or relocating employees, all the money will go down the drain and will have to be redone. If you make SCS by footage, then SCS will not be an attribute of the current state of affairs in the company, but an element of the premises (building), it becomes a capital investment in real estate, increasing its market value and versatility of use.
Switching
(this applies to the case when SCS is on several floors).We can drag all the wires to the server room. There will be a LOT of them. In one of the organizations I worked for, this tourniquet could barely be wrapped around, almost a meter in diameter. The advantage of this is the very versatility - the wires go in a straight line (in the sense, without breaking the electrical connection), you can include anything in them - from a telephone to a video camera.
And we can do smarter. We lay the vertical part of the SCS (interfloor connections), on each floor we allocate a nook into which the wires from the floors converge. In principle, there can be even more than one such nooks on the floor.
SCS on the floor - universal. Interfloor SCS - specialized.
Interfloor SCS: between floors there is a gigabit, or even all ten, or even optics, or even ... (do not forget about modesty in this place, and stop at gigabit), a switch is installed. Telephony goes down in a multi-multi-pair cable, which is bred to patch panels or crosses (crowns 66 or something similar). Further, the universal SCS of the floor is switched between the options “telephony”, “ethernet”, “signaling”, etc. as you like.
The advantage of this solution is that several thick telephony wires converge into the server room (which are connected to the PBX and you can no longer think about them), several gigabit (10 gigabit) cables converging to the switches (apparently, to the distribution level, if you follow the ciss scheme). The server room is free from wires, everything "low" user is taken out of the server room. There is no need for non-essential personnel to drop in to lay wires for a transplanted employee, only everything Very Important remains there.
However, these pluses come with some minuses. The removal of a part of the equipment from the server room to the switching room (it is clear that in a good way it should be a small room, in reality it is usually a switching box under the ceiling, or even on the floor in one of the offices) leads to an increase in the vulnerability of the SCS. Dust, dirt - this is the first. Second - unauthorized access(you enable a person to carry out a perfect man-in-middle attack in a back corner of a building) and hooliganism. Third, SCS is losing its versatility. And what if there were not enough telephone pairs for the floor? And below the floor, 10 pairs out of 200 are used ...
aggressive branching
(I don't know what this scheme is officially called)Instead of a single switch room, we make many shelves. Relatively speaking, for every 1-2 rooms there is a separate switching shelf. It comes with 1 ethernet and 1 somewhat paired telephone cable. This scheme is intermediate. On the one hand, you have fewer wires from the server room (not by the number of jobs, but by the number of cabinets), on the other hand, the SCS of a separate room can be redone with little blood. These are pluses.
Cons - the same problem of unbalanced applications (if there was not enough telephony in the room, what do we do?), a lot of places where shelves are located (these places are not always obvious and well documented, I somehow found such a switching room in the middle of the room above the false ceiling) . Accommodation electrical equipment(switches) requires power (PoE can be partially smoothed, but it's expensive...).
This solution has "the most cheap option” is a hub (switch) under your feet or in a corner. Several wires go to the switches from the server room, wires go from these switches to neighboring switches ... This way you can provide a couple of hundred sockets at the cost of 3-4 bays (300m * 4 = 1.2km) of wires, several desktop switches and patch cords, which are usually not patch cords, but that the same twisted pair, but compressed. [Reference: monolithic twisted pair (in which each wire is solid copper) has best performance, but low mechanical strength, "real" patch cords have stranded fibers, which are worse for data transmission, but better survive bends, steps, pinching chairs and tables]. It is from this option that you should run like hell from incense, because it will cause so many problems that it cannot be described in words (switches will lose power, freeze, cables will get confused and dirty ... I don’t even want to remember this).
Switching and shelves
The most radical option: a vertical cable network comes to the floor, a horizontal cable network goes from the floor, to the shelves in the rooms, from the shelves in the rooms there is an “internal SCS” to sockets in the workplace.Pluses - the sum of the pluses of the previous ones.
Cons - the same, but there is one more: the more switching occurs with the application, the worse the signal (this is not about switches, of course, although they also increase the delay, which can be unpleasant in some applications). 8 connectors from the phone to the PBX is quite a worthy reason to start wheezing into the handset in a year or two.
An interesting feature of this solution is that it fits perfectly with the core-distribution-access model. At the same time, the most important wires are interfloor wires, they usually run in a box, there are few of them (this is important, because it is easier to make a small box), they are well protected (perhaps inside the walls).
And what for all these wires?
And here another interesting scheme is drawn, these are wifi and dect. If instead of SCS by rooms it is placed indoors wifi hotspots access and dect "new telephone bases, the number of wires will be significantly reduced.However, this still does not solve the problem of bringing the wire to the floor (room), and the quality / speed of wifi with good ethernet is not comparable (both in terms of delay and the probability of packet loss).
What to choose?
We return to the first points again. First you must decide how the sockets will be distributed. By person, or by square meters.Next, you need to calculate how many wires there will be. If it is less than a couple of hundred (and if the length of the wires fits within the 100m limit), you should not mess with the switching ones. If there are a lot of wires, or long distances- it is worth thinking about switching. If there is at least the slightest opportunity to win back the premises, and not the cabinets, you need to fight for the premises. No windows, no batteries, no walk-through doors. Just a closet.
Which wire to choose? In fact, any, the cheapest, on which the contractor is ready to vouch for the quality. The cheapest certifiable wires (able to certify) perform just as well as silver oxygen-free copper twisted-pair wire with ferrite piercings.
But with sockets and patch panels, everything is much worse. Bad sockets are an eternal torment for the administrator.
So what is a good outlet?
- The core should hold up well. If it's on screws, great. Auto-latches often break and then hang out with worms inside the box.
- Tilt down or lid - a small plus (less dusty)
- The twisted-pair crimp should be using a striker, not a plastic cap with teeth. These teeth crimp the pair worse than the drummer.
- Durable (sorry for the banality): it should normally hold the wire, not creak when the wire moves inside the outlet. She has been working for years, and no one promises that the wires will be plugged in / out neatly.
Telephony patch panels are the place for holivars. To begin with: should telephony be distributed on patch panels or crowns? If on crowns - it is compact, very compact. If on a patch panel, switching can be done without a drummer and force.
Similar holivars are around patch panels for ethernet. Are they needed or not? After all, the wires can come "directly" and stick into the switches. At the same time, there are fewer mechanical contacts and unwinding, i.e. the path is more reliable. From the side of supporters: patch panels allow you to organize the economy right. As experience shows, if there are a lot of free units, then patch panels are installed. If there are few units, then they usually sting.
Which option to choose is up to you.
Numbering
Minus the wires, the second (and maybe even the first) value of the SCS is its circuitry. The diagram should show which socket goes where and HOW it goes (i.e., the places where the wires pass must be clearly drawn on the building plan). Even more important is the presence of socket numbers both at the sockets themselves and from the “server” side (that is, from the side that is wired on the patch panel or in the switching rooms). If there are no numbers, you can throw out the SCS (or start a long painful numbering procedure). Numbers should be written in a way that is easy to read (i.e. handwritten numbers - not so much), and so that they remain for years. Those. Pencil is definitely no.Do I need to number patch cords between patch panels and equipment when switching? I used to think yes. Now - I doubt it, because in the correct SCS these wires are obviously visible and easy to find.
patch cords
Well, the last. Patch cords MUST be with a cap, a cap, a reverse tab... Anything that will protect the jack latch from snagging on the wires when pulling the wire through the neighbors. IT IS IMPORTANT. Trust me, I personally struggled with 400+ wires WITHOUT caps. This is AD. Instead of a simple “pull and pull out”, you have to manually unravel each wire from its neighbors, the unraveling process splits the neatly laid wires, prevents you from pulling out other wires ... A cap (or at least a plug at the back) is MANDATORY.
Add-ons
Thanks to the commenters. Moments not described.- Switch log. I don’t know how it looks “good” in theory, in my work it looked like a tabular file in which there was a list of sockets and an indication of “to whom” this or that socket was assigned. There was an attempt to number the patch cords, but it gradually died out due to general laziness. Apparently, in theory, for each switching room there should be a log in which it says “socket such and such - socket such and such” (port of such and such device of such and such).
- If patch cords have already been purchased without caps, electrical tape is used as an emergency solution. Although she gets dirty and gets in the way. caps are better
- It is good to have organizers under the patch panels. Priceless units are spent on this, however, the SCS acquires accuracy and completeness.
- If you give SCS to the contractor, do not skimp on paying for the preparation of the TOR. They (contractors) will make it more reasonable. Agree on their (reasonable) project, making adjustments and explaining what you want better than ... m ... inventing your TK
- Standards for further google: EN 50173, ISO/IEC 11801
- For those who want to look at beautiful racks with beautifully laid wires:
Basic concepts
Structured Cabling System (SCS)- this is a universal cable system of a building, a group of buildings, designed to be used for a sufficiently long period of time without restructuring, SCS involves the replacement of the entire cable system and building / building systems ..
The versatility of the SCS implies its use for various systems:
- computer network;
- telephone network;
- security system;
- fire alarm
- others.
Such a cable system is independent of the terminal equipment, which allows you to create a flexible communication infrastructure of the enterprise. A structured cabling system is a collection of passive communication equipment:
Cable- this component is used as the SCS data transmission medium. The cable is divided into shielded and unshielded.
Sockets- this component is used as an entry point to the cable network of the building.
Patch panels- are used to administer cable systems in the switching centers of the floors and the building as a whole.
Patch Cords- are used to connect office equipment to the cable network of the building, organize the structure of the cable system in switching centers.
The principle of building SCS
SCS - covers the entire space of the building, connects all points of the means of information transmission, such as computers, telephones, fire sensors and burglar alarm, video surveillance and access control systems. All these facilities are provided by an individual entry point in common system building. Lines, separate for each information outlet, connect the entry points to the floor switching center, forming horizontal cable subsystem. All storey switching nodes are connected by special trunks in the switching center of the building. External cable lines are also brought here to connect the building to the global information resources such as telephony, internet, etc. This topology allows you to reliably manage the entire building system, provides flexibility and simplicity of the system, as well as its unification.
1 - Office equipment- computer, telephone, fax and other peripheral equipment.
2 - Cabling- it is laid along embedded channels inside walls, along decorative cable ducts inside rooms, along trays behind false ceilings or under false floors.
3 - Switching node- designed for installation and use of switching equipment of the cable system, for centralizing external and internal cable entries, for connecting the cable system with active network or other equipment.
4 - Vertical cabling
5 - Service technical means
Workplace- the area where the technical means of the user are installed, connected to the cable network of the building. The workplace is equipped with at least two information outlets, as a typical office workplace contains at least the user's computer and phone. To connect them to the SCS, sockets with a standardized RJ-45 connector and patch cords with a length of 1 to 5 meters are used.
Horizontal cabling- cable lines connecting the workplace with the switching node of the floor. Horizontal cabling, based on copper conductors, uses a four-pair single-core cable in various designs. Under normal conditions, unshielded cable is used, and with increased requirements for electromagnetic radiation, compatibility or confidentiality, shielded cable. In separate special occasions can be used as a horizontal cable system fiber optic cable providing increased protection against electromagnetic radiation and protection against unauthorized access.
Floor Switching Unit- the area where the horizontal cabling lines converge, the switching equipment is located and the floor's cabling system is administered. Administration refers to making changes and additions to existing configurations. The basis of such centers are patch and cross-panels. For ease of installation and ease of use, switching equipment is placed in special cabinets and racks, to which all cable lines are connected. Cabinets also perform the function of restricting access to switching equipment.
Vertical cabling- cable lines connecting the switching node of the floor with the switching center of the building.
Backbone subsystem- a subsystem of a building complex, which can be constructed from copper and/or fiber optic types of cable, and which integrates the cable systems of buildings.
In each specific building general case there are three SCS subsystems: vertical cable subsystem, horizontal cable subsystem and workstation subsystem. For fairly large buildings, with big amount workplaces on the floors, all these three subsystems are present explicitly. For relatively small buildings with a limited number of jobs, it is recommended to organize one SCS switching node, where all horizontal cabling converges. In this case, the vertical cable subsystem may be absent or may be of a degenerate nature, in which the vertical cable subsystem is represented by a set of patch cords connecting the ports of the "floor" LAN switches (switches for connecting workplaces) with the ports of the central (backbone) switch.
Requirements for the design of SCS:
SCS should be designed with redundancy in terms of the number of connections.
A structured cabling system must be made in accordance with standards - international, European, American. such as ANSI/EIA/TIA 568, ANSI/EIA/TIA 569
The workplace must have at least one LAN connection and one telephone network connection
The maximum horizontal wiring distance should not exceed 90m;
The equipment used to build the SCS must comply with at least the fifth category.
Each link of the cable system from the point of connection of the terminal equipment to the point of connection to the patch panel must be tested for belonging to at least the fifth category.
SCS should provide fast switching of horizontal wiring lines and building mains
Cable laying in the corridors should be carried out behind a false ceiling, if any, and in its absence - in specialized cable channels (boxes) or in existing mortgages; in the working premises, the cable is supplied to the workplaces in cable channels.
