At this stage, the concept of the future facility is being developed and the main technical and economic characteristics are being determined. The sketch determines the placement of the object on the ground, its volumetric-spatial solution, and structural diagram. Also at this stage, the main engineering loads for water, heat and electricity are calculated, the so-called. calculation of loads.

Development Stages of "PP"

Stage 2 - PD. Project documentation

4.2. Working documentation
4.2.1. The working documentation transferred to the customer includes:
- working drawings intended for construction and installation work;
- attached documents developed in addition to the working drawings of the main set.
4.2.2. The main sets of working drawings include general data on working drawings, drawings and diagrams provided for by the relevant standards of the Design Documentation System for Construction (hereinafter referred to as SPDS).
...
4.2.6. The attached documents include:
- working documentation for construction products;
- sketch drawings of general types of non-standard products, made in accordance with GOST 21.114;
- specification of equipment, products and materials, carried out in accordance with GOST 21.110;
- questionnaires and dimensional drawings, carried out in accordance with the data of the equipment manufacturers;
- local estimate according to forms;
- other documents provided for by the relevant SPDS standards.
The specific composition of the attached documents and the need for their implementation are established by the relevant SPDS standards and the design assignment.
...
4.2.8. In working drawings it is allowed to use standard building structures, products and assemblies by referring to documents containing working drawings of these structures and products. Reference documents include:
- drawings of standard structures, products and components;
- standards, which include drawings intended for the manufacture of products.
Reference documents are not included in the working documentation transferred to the customer. The design organization, if necessary, transfers them to the customer under a separate agreement.

Construction works, associated with the construction of buildings are divided into general construction and special types.

Civil works These are actions aimed at the construction of the building itself, including finishing work.

Special works, this is the installation of utilities and other actions aimed at ensuring the functionality of buildings such as: ventilation, water supply, sewerage, gas supply, electric lighting, telephone installation and landscaping of the surrounding area.

Each such set of documents is assigned a name and characteristic brand, which is placed on the drawing in the main inscription. The brand is made up of initial capital letters the name of the original part of the project.

Name of the main set of working drawings	Brand
Production technology	TX
Technological communications	TK
General plan and transport facilities	GT
General plan	GP
Architectural solutions	AR
Interiors	AI
Reinforced concrete structures	QoL
Wooden structures	KD
Architectural and construction solutions	AC
Metal structures detailing	KMD
Water supply and sewerage	VC
Heating, ventilation and air conditioning	OB
Thermomechanical solutions for boiler houses	TM
Air supply	Sun
Dust removal	PU
Refrigeration	HS
Gas supply ( internal devices)	FGP
Power equipment	EM
Electric lighting (internal)	EO
Communication systems	SS
Radio communications, radio broadcasting and television	RT
Firefighting	PT
Fire alarm	PS
Security and fire alarm systems	OS
Hydraulic solutions	GR
Automation...	A...
Comprehensive automation	AK
Anti-corrosion protection of building structures and structures	AZ
Anti-corrosion protection of technological devices, gas ducts and pipelines	AZO
Thermal insulation of equipment and pipelines	TI
Car roads	HELL
Railways	pancreas
Transport structures	TR
External water supply networks	NV
External sewerage networks	NK
External water supply and sewerage networks	NVK
Thermomechanical solutions for heating networks	TS
External gas pipelines	GOS
Outdoor electric lighting	EN
Electricity supply	ES

Note:

If necessary, additional brands of working drawings can be assigned. In this case, no more than three are used for brands capital letters Russian alphabet, selected, as a rule, from the initial letters of the names of the set of drawings

A... - the ellipsis is replaced by the brand of the selected set of working drawings.

The mark applied to the drawing consists of a letter abbreviation indicating which set of working drawings of the project this document belongs to and numbers indicating its serial number.

AC4 - Architectural and construction solutions with serial number 4

KZh12 - Reinforced concrete structures with serial number 12

The drawings according to which building structures are manufactured in factories are called procurement drawings.

In the process of erecting buildings and structures, they often make some changes in the layout of the premises or completely replace some structures with others. In such cases, appropriate changes are made to these drawings or the drawings are redone.

Drawings that fully reflect the layout of the premises of the building under construction, its dimensions and characteristic structures are called as-built.

Drawings of buildings developed on the basis of measurements are called measuring drawings.

Project of TM and ATM of production and administrative buildings of the enterprise. The ATM section is common to 2 buildings.

Composition and examples of drawings of TM and ATM sections

Project TM of the production building:

Total information

To prepare hot water, a Buderus logalux ST 200 water heater tank with a capacity of 200 liters is provided.

The circulation in the heating system is forced using WILO-Top-S pumps.

The thermal expansion of water is compensated by a Reflex N100 membrane expander with a capacity of 100 liters.

The operation of boiler equipment is carried out by the boiler room operator.
Firewood is stored in a specially designated place on the territory of the organization under a canopy.

Project TM of the administrative building:

Total information
Technological diagram of boiler room pipelines
Fragment of the layout plan for boiler room equipment M 1:50. Cut 1-1,2-2.

The boiler room has a gas generator boiler running on solid fuel (wood) VITOLIG 150 (VIESSMANN), with a thermal power of 40 kW.
The circulation in the heating system is forced using WILO-Star-RS pumps.
The heating circuit is fed through an automatic valve (VF 06).
Thermal expansion of water is compensated by the Reflex membrane expander
N50 with a capacity of 50 liters.

ATM project for the administrative building:

Total information
Automation scheme.
Schematic diagram of electrical control of circulation pumps.
Return pressure alarm.
Basic electrical diagram and connections of external wiring.
Circulation pumps. Connection diagram for external wiring.
Fragment of the plan at OTM.0.000

The ATM section provides automation of the operation of circulation pumps depending on the decrease or increase in pressure in the network. When the pressure in the network decreases, one of the pumps turns on, and when the pressure increases, it turns off. The pumps are mutually redundant. It is possible to select a reserve when one of the pumps is not working.

Light and sound signaling of the circuit operation is provided in the form of a signal post PS-1U2, which is installed locally in the boiler room. Pressure control in the return pipeline is provided by installing an electric contact pressure gauge with a light and sound signal transmitted to the AS-13 light signaling device.

It is customary to develop design documentation for construction in several stages, which differ in the composition and depth of elaboration of design solutions. The basic requirements for the preparation of documentation at various stages are set out in GOST R 21.1101-2009.

Let's consider all stages of the project in order:

• Stage 2 - PD. Design documentation

Stage 1 - PP. Pre-design studies (Sketch design)

At this stage, the concept of the future facility is being developed and the main technical and economic characteristics are being determined. The sketch determines the placement of the object on the ground, its volumetric-spatial solution, design diagram. Also at this stage, the main engineering loads for water, heat and electricity are calculated, the so-called. calculation of loads.

Development Stages of "PP" is not mandatory, but helps save time and money during further design.

Stage 2 - PD. Project documentation

Unlike the preliminary design Stage "Project"(“PD” or simply “P”) is mandatory and subject to approval by state executive authorities. Based on the results of the approval of the “Project” Stage, a permit for the construction of the facility is issued. Composition and content this stage regulated by Decree of the Government of the Russian Federation No. 87 of February 16, 2008. Of course, the composition will be individual for each project, but we will try to compile the most complete list of all possible sections and subsections of the “PD” Stage:

Number	Section code	Section title
		Explanatory note
		Explanatory note
		Initial permitting documentation
		Scheme of planning organization of a land plot
		Architectural solutions
		Constructive and space-planning solutions
		Reinforced concrete structures
		Metal constructions
		Wooden structures
		Static calculation
		Information about engineering equipment, engineering support networks, a list of engineering activities, the content of technological solutions.
Subsection 1		Power supply system
		Outdoor power supply
		Power equipment
		Electric lighting
Subsection 2		Water supply system
		External water supply
		Domestic water supply
Subsection 3		Drainage system
		External drainage
		Internal drainage
Subsection 4		Heating, ventilation and air conditioning, heating networks
		Heating and ventilation
		Heat supply
		Individual heating point
Subsection 5		Communication networks
		CCTV
		Security alarm
		Other low current systems
Subsection 6		Gas supply system
		Outdoor gas supply
		Domestic gas supply
Subsection 7		Technological solutions
		Technological solutions
		Air supply
		Refrigeration
		Steam supply
		Dust removal
		Other technological systems
		Construction organization project
		Project for organizing work on demolition or dismantling of capital construction projects
		List of security measures environment
		Draft technological regulations for the management of construction waste at the site
		Engineering and environmental surveys
		Measures to ensure fire safety
		Measures to ensure access for people with disabilities
Section 10(1)		Measures to ensure compliance with energy efficiency requirements and equipment requirements for buildings, structures and structures metering devices for used energy resources
		Monitoring prices for materials
		Other documentation in cases provided for Federal laws
		Lighting calculations of insolation and natural illumination (KEO)
		Measures to protect against noise and vibration. Assessment of noise impact for the period of operation of the facility
	ITM GOiChS	Engineering and technical measures of civil defense. Measures to prevent emergency situations
		Building Operating Instructions
		Measures to counter terrorist acts
		Declaration of industrial safety of hazardous production facilities

Stage 3 - RD. Working documentation

Stage "RD" It is needed primarily by builders, since it develops design solutions in the most complete and detailed manner, which were only indicated in the “PD” Stage. Unlike "P", "Rabochka" includes drawings of components, axonometric diagrams and profiles utility networks, specifications, etc. On the other hand, at the working stage, the documentation is deprived of some sections, the completeness of which was exhausted at the design stage (for example, PIC, Environmental Protection, KEO, ITM GOiES, etc.). As at Stage “P”, the composition of the “Working Documents” will be individual for each project, but we will try to compile the most complete list of all possible sections of the “Working Documentation” Stage:

Section code	Section title
	General plan
	Transport structures
	General plan and transport (when merging GP and TR)
	Car roads
	Railways
	Architectural solutions
	Architectural and construction solutions (when combining AR and KR)
	Interiors
	Constructive decisions. Reinforced concrete structures
	Constructive decisions. Reinforced concrete structures. Foundations
	Constructive decisions. Metal constructions
	Constructive decisions. Metal structures detailing
	Constructive decisions. Wooden structures
	Constructive decisions. Static calculation
	Hydraulic solutions
	Power supply system. Outdoor power supply
	Power supply system. Power equipment
	Power supply system. Electric lighting
	Power supply system. Outdoor electric lighting
	Power supply for engineering systems
	Water supply system. External networks
	Drainage system. External networks
	Water supply and drainage system. External networks
	Water supply and drainage system. Internal networks
	Heating, ventilation and air conditioning
	Heat supply
	Thermomechanical solutions (Boiler room, ITP, etc.)
	Telephony, Radio, Telereception
	Structured Cabling Networks
	Automation of engineering systems
	Automation technological processes
	Complex automation (when combining AIS and ATP)
	CCTV
	Security alarm
	Access control and accounting system
	Outdoor gas supply
	Domestic gas supply
	Technological solutions
	Technological communications
	Air supply
	Refrigeration
	Steam supply
	Dust removal
AUPS - SOUE	Automatic installation fire alarm, Fire warning and evacuation control system
	Automatic fire protection
	Special fire extinguishing (water, powder, etc.)
	Estimates for the construction of capital construction projects
	Monitoring prices for materials
	Anti-corrosion protection
	Thermal insulation of equipment and pipelines

GOST R 21.1101-2009 Design documentation system:

4.2. Working documentation
4.2.1. The working documentation transferred to the customer includes:
- working drawings intended for construction and installation work;
- attached documents developed in addition to the working drawings of the main set.
4.2.2. The main sets of working drawings include general data on working drawings, drawings and diagrams provided for by the relevant standards of the Design Documentation System for Construction (hereinafter referred to as SPDS).
...
4.2.6. The attached documents include:
- working documentation for construction products;
- sketch drawings of general types of non-standard products, made in accordance with GOST 21.114;
- specification of equipment, products and materials, carried out in accordance with GOST 21.110;
- questionnaires and dimensional drawings, carried out in accordance with the data of the equipment manufacturers;
- local estimate according to forms;
- other documents provided for by the relevant SPDS standards.
The specific composition of the attached documents and the need for their implementation are established by the relevant SPDS standards and the design assignment.
...
4.2.8. In working drawings it is allowed to use standard building structures, products and assemblies by referring to documents containing working drawings of these structures and products. Reference documents include:
- drawings of standard structures, products and components;
- standards, which include drawings intended for the manufacture of products.
Reference documents are not included in the working documentation transferred to the customer. The design organization, if necessary, transfers them to the customer under a separate agreement.

SNiP 11-01-95 Composition of working documentation:

5.1. The composition of the working documentation for the construction of enterprises, buildings and structures is determined by the relevant state SPDS standards and is specified by the customer and the designer in the design agreement (contract).

5.2. State, industry and republican standards, as well as drawings of standard structures, products and assemblies, which are referenced in the working drawings, are not included in the working documentation and can be transferred by the designer to the customer if this is stipulated in the contract.

The main goal of the center is to assist in construction, both for developers and buyers of real estate.

The main areas of activity are:

1. Preparation of design documentation for construction
2. Conducting an examination of design documentation to obtain a construction permit.
3. Conducting geological and geodetic surveys
4. Obtaining technical conditions for construction
5. Carrying out construction, technical and forensics
6. Industrial safety examination
7. Construction and installation work of any complexity

By contacting us, any client receives free consultation for construction and assistance in selecting a contractor.

Main region of service provision:

G. Eagle and Oryol region.

G. Kursk and Kursk region.

G. Belgorod and Belgorod region.

ATM technology is a telecommunications concept defined by international standards for the transmission of the full range of user traffic, including voice, data and video signals. It was developed to meet the needs of a digital network of broadband services and was originally intended for the integration of telecommunication networks. The ATM abbreviation stands for Asynchronous Transfer Mode and is translated into Russian as “asynchronous data transfer”.

The technology was created for networks that must handle both traditional high-throughput data traffic (such as file transfers) and real-time, low-latency content (such as voice and video). The reference model for ATM maps roughly to the three lowest ISO-OSI layers: network, data link, and physical. ATM is the primary protocol used over the SONET/SDH (stationary telephone network) backbone. common use), as well as the Integrated Services Digital Network (ISDN).

What it is?

What does ATM mean for a network connection? It provides functionality similar to circuit switching and packet switching networks: the technology uses asynchronous time division multiplexing and encodes data into small fixed-size packets (ISO-OSI frames) called cells. This differs from approaches such as Internet Protocol or Ethernet, which use variable-sized packets and frames.

The basic principles of ATM technology are as follows. It uses a connection-oriented model in which a virtual circuit must be established between two endpoints before the actual communication can begin. These virtual circuits can be “persistent,” which are dedicated connections that are typically preconfigured by the service provider, or “switchable,” which are customizable on a per-call basis.

Asynchronous Transfer Mode (ATM) is known as a communication method used in ATMs and payment terminals. However, this use is gradually declining. The use of technology in ATMs has largely been replaced Internet Protocol(IP). In the ISO-OSI reference channel (layer 2), the underlying transmission devices are usually called frames. In ATM, they have a fixed length (53 octets or bytes) and are specifically called "cells".

Cell size

As noted above, ATM decryption is an asynchronous data transfer carried out by dividing it into cells of a certain size.

If the voice signal is reduced to packets and they are forced to be carried by a link with heavy data traffic, then no matter what their sizes are, they will encounter large full-blown packets. Under normal waiting conditions, they may experience maximum delays. To avoid this problem, all ATM packets or cells are the same small size. Additionally, the fixed cell structure means that data can be easily transferred by hardware without the inherent delays introduced by software switched and routed frames.

Thus, ATM designers used small data cells to reduce jitter (in in this case delay variance) in multiplexing This is especially important when carrying voice traffic, since the conversion of digitized voice to analog audio is an integral part of the real-time process. This helps the decoder (codec), which requires a uniformly distributed (over time) stream of data elements. If the next in line is not available when needed, the codec has no choice but to pause. Subsequently, the information is lost because the period of time when it should have been converted into a signal has already passed.

How did ATM develop?

During the development of ATM, 155 Mbit/s synchronous digital hierarchy (SDH) with a 135 Mbit/s payload was considered fast optical network, and many of the plesiochronous digital hierarchy (PDH) links on the network were significantly slower (no more than 45 Mbit/s). At this speed, a typical full-size 1500-byte (12,000-bit) data packet should be downloaded in 77.42 microseconds. On a low-speed link such as a 1.544 Mbps T1 line, transmission of such a packet took up to 7.8 milliseconds.

The download delay caused by several such packets in the queue can exceed the 7.8 ms number by several times. This is unacceptable for voice traffic, which must have low jitter in the data stream fed to the codec to produce good quality audio.

A voice packet system can do this in several ways, such as using a playback buffer between the network and the codec. This helps smooth out jitter, but the delay that occurs when passing through the buffer requires an echo canceller, even on local networks. At the time it was considered too expensive. Additionally, it increased latency across the link and made communication more difficult.

ATM is inherently low jitter (and minimal total delay) for traffic.

How does this help in network connection?

The ATM design is for a low-jitter network interface. However, "cells" were introduced into the design to provide short queuing delays while still supporting datagram traffic. ATM technology broke all packets, data, and voice streams into 48-byte chunks, adding a 5-byte routing header to each chunk so they could be reassembled later.

This choice of size was political, not technical. When CCITT (now ITU-T) standardized ATM, the US representatives wanted a 64-byte payload as it was considered a good compromise between large amounts of information optimized for data transfer and shorter payloads designed for real-time applications . In turn, developers from European countries wanted 32-byte packets because small sizes(and therefore low transmission time) simplify voice applications regarding echo cancellation.

As a compromise between the two sides, a size of 48 bytes was chosen (plus header size = 53). The 5-byte headers were chosen because 10% of the payload was considered to be the maximum cost to pay for routing information. ATM technology multiplexed 53-byte cells, which reduced data corruption and latency by nearly 30 times, reducing the need for echo cancellers.

ATM cell structure

ATM defines two different formats cells: custom network interface(UNI) and network interface (NNI). Most ATM network links use UNI. The structure of each such package consists of the following elements:

• The Generic Flow Control (GFC) field is a 4-bit field that was originally added to support ATM interconnection in the network public access. The topology is represented as a ring with a double distributed queue bus (DQDB). The GFC field was designed to provide 4 User-Network Interface (UNI) bits to negotiate multiplexing and flow control among cells various connections ATM. However, its use and exact values ​​have not been standardized, and the field is always set to 0000.
• VPI - identifier virtual path(8 bits UNI or 12 bits NNI).
• VCI - virtual channel identifier (16 bits).
• PT - payload type (3 bits).
• MSB - network management cell. If its value is 0, the user data packet is used, and in its structure, 2 bits are Explicit Forward Congestion Indication (EFCI), and 1 is network congestion experience. In addition, 1 more bit is allocated for the user (AAU). It is used by AAL5 to indicate packet boundaries.
• CLP - cell loss priority (1 bit).
• HEC - Header Error Control (8-bit CRC).

The ATM network uses the PT field to designate various special cells for operations, administration, and management (OAM) purposes, as well as to define packet boundaries in some adaptation layers (AALs). If the MSB value of the PT field is 0, it is a user data cell, and the remaining two bits are used to indicate network congestion and as a header bit general purpose, available for adaptation levels. If MSB is 1, it is a control packet, and the remaining two bits indicate its type.

Some (asynchronous data transfer methods) use the HEC field to control a CRC-based framing algorithm that allows cells to be found at no extra cost. An 8-bit CRC is used to correct single-bit header errors and detect multi-bit ones. When the latter are found, the current and subsequent cells are discarded until a cell without header errors is found.

The UNI packet reserves the GFC field for local system flow control or submultiplexing between users. This was intended to allow multiple terminals to share one network connection. Also this technology was used to allow two integrated service digital network (ISDN) telephones to share one basic ISDN connection at a specified speed. All four GFC bits must be zero by default.

The NNI cell format replicates the UNI format in much the same way, except that the 4-bit GFC field is remapped into the VPI field, expanding it to 12 bits. Thus, one NNI ATM connection can handle almost 216 VCs every time.

Cells and transmission in practice

What does ATM mean in practice? It supports various types of services through AAL. Standardized AALs include AAL1, AAL2 and AAL5, as well as the rarely used AAC3 and AAL4. The first type is used for constant bit rate (CBR) services and circuit emulation. Synchronization is also supported in AAL1.

The second and fourth types are used for variable bit rate (VBR) services, AAL5 for data. Information about which AAL is used for a given cell is not encoded in it. Instead, it is negotiated or configured at the endpoints for each virtual connection.

After the initial design of this technology, networks began to operate much faster. A 1500-byte (12,000 bit) full-length Ethernet frame requires only 1.2 μs to transmit over a 10 Gbps network, reducing the need for small cells to reduce latency.

What are the strengths and weaknesses of such a relationship?

The advantages and disadvantages of ATM network technology are as follows. Some believe that increasing communication speeds will allow it to be replaced by Ethernet in the backbone network. However, it should be noted that increasing the speed alone does not reduce jitter due to queuing. Besides, Hardware to implement service adaptation for IP packets is expensive.

However, due to the fixed payload of 48 bytes, ATM is not suitable as a data link directly under IP, since the OSI layer on which IP operates must provide maximum block transmission (MTU) of at least 576 bytes.

On slower or congested connections (622 Mbps and below), ATM makes sense, and for this reason most asymmetric digital subscriber line (ADSL) systems use this technology as an intermediate layer between the physical link layer and the Layer 2 protocol, such like PPP or Ethernet.

At these lower speeds, ATM provides useful opportunity carry several logic circuits on a single physical or virtual medium, although there are other methods such as multilink PPP and Ethernet VLANs that are optional in VDSL implementations.

DSL can be used as a method of accessing an ATM network, allowing you to connect to many Internet service providers through a broadband ATM network.

Thus, the disadvantages of the technology are that it loses its effectiveness in modern high-speed connections. The advantages of such a network are that it significantly increases the bandwidth, since it provides a direct connection between various peripheral devices.

Moreover, if there is one physical connection With the help of ATM, several different virtual channels with different characteristics can operate simultaneously.

This technology uses quite powerful tools designed for traffic management, which continue to develop to this day. This makes it possible to transmit data simultaneously various types, even if they have completely different requirements for sending and receiving them. So, you can create traffic carried out via various protocols, on one channel.

Fundamentals of Virtual Circuit Operation

Asynchronous Transfer Mode (abbreviated as ATM) operates as a link-based transport layer using virtual circuits (VCs). This is related to the concept of virtual paths (VPs) and channels. Each ATM cell has an 8- or 12-bit Virtual Path Identifier (VPI) and a 16-bit Virtual Circuit Identifier (VCI) defined in its header.

The VCI, together with the VPI, is used to identify the next destination of a packet as it passes through a series of ATM switches on its way to its destination. The VPI length varies depending on whether the cell is sent over the user interface or the network interface.

As these packets pass through the ATM network, switching occurs by changing the VPI/VCI values ​​(switching labels). Although they do not necessarily agree on the ends of the connection, the concept of the circuit is sequential (unlike IP, where any packet can take a different route to its destination). ATM switches use the VPI/VCI fields for virtual circuit identification (VCL) next network, which the cell must transit on its way to its final destination. The VCI function is similar to the data link connection identifier (DLCI) function in frame relay and logical channel group number in X.25.

Another advantage of using virtual circuits is that they can be used as a multiplexing layer, allowing the use of different services (such as voice and frame relay). VPI is useful for reducing the switching table of some virtual circuits that share common paths.

Using cells and virtual circuits to organize traffic

ATM technology additionally includes traffic movement. When a circuit is configured, each switch in the circuit is informed of the connection class.

ATM traffic contracts are part of the mechanism that ensures “quality of service” (QoS). There are four main types (and several variants), each of which has a set of parameters that describe the connection:

• CBR - constant data transfer rate. The peak rate (PCR) is indicated and is constant.
• VBR - variable bit rate. The average or steady-state CR (SCR) value is indicated, which can peak at a certain level for the maximum interval before problems arise.
• ABR - available data transfer rate. The minimum guaranteed value is specified.
• UBR - undefined data transfer rate. Traffic is distributed across all remaining bandwidth.

VBR has real-time options, and in other modes serves "situational" traffic. Invalid times are sometimes shortened to vbr-nrt.

Most traffic classes also use the concept of cell variation tolerance (CDVT), which defines their "aggregation" over time.

Data transfer control

What does ATM mean considering the above? To maintain network performance, traffic rules may be applied to virtual networks, limiting the amount of data transferred at connection entry points.

The reference model validated for UPC and NPC is the General Cell Rate Algorithm (GCRA). In general, VBR traffic is usually controlled using a controller, unlike other types.

If the amount of data exceeds the traffic determined by the GCRA, the network can either drop cells or flag the Cell Loss Priority (CLP) bit (to identify the packet as potentially redundant). Most security work works on a sequential monitoring basis, but this is not optimal for encapsulated packet traffic (since dropping one unit will discard the entire packet). As a result, schemes such as Partial Packet Discard (PPD) and Early Packet Discard (EPD) have been created, which are capable of discarding an entire series of cells until the next packet begins. This reduces the number of useless pieces of information on the network and saves bandwidth for complete packets.

EPD and PPD work with AAL5 connections because they use the packet marker end: ATM user interface (AUU) indication bit in the Payload Type field of the header, which is set in the last cell of the SAR-SDU.

Traffic shaping

The basics of ATM technology in this part can be presented as follows. Traffic shaping typically occurs at the network interface card (NIC) in the user equipment. This attempts to ensure that the flow of cells on the VC will comply with its traffic contract, that is, units will not be discarded or de-prioritized in the UNI. Because the reference model GCRA is the algorithm defined to control traffic on the network; this algorithm is usually used to generate and route data.

Types of virtual circuits and paths

ATM technology can create virtual circuits and paths both statically and dynamically. Static circuits (SPS) or paths (PVP) require that the circuit consist of a series of segments, one for each pair of interfaces through which it passes.

PVP and PVC, although conceptually simple, require significant effort in large networks. They also do not support re-routing a service in the event of a failure. In contrast, dynamically constructed SPVP and SPVC are constructed by specifying the characteristics of a schema (service "contract") and two endpoints.

Finally, ATM networks create and delete switched virtual circuits (SVCs) as required by the end piece of equipment. One application for SVC is to carry individual telephone calls when a network of switches is interconnected via ATM. SVCs have also been used in attempts to replace local networks ATM.

Virtual routing scheme

Most ATM networks that support SPVP, SPVC, and SVC use the Private Network Node interface or the Private Network-to-Network Interface (PNNI) protocol. PNNI uses the same shortest path algorithm used by OSPF and IS-IS to route IP packets to exchange topological information between switches and select a route through the network. PNNI also includes a powerful summation mechanism allowing for very large networks, and a call access control (CAC) algorithm that determines the availability of sufficient bandwidth along a proposed route through the network to satisfy the service requirements of a VC or VP.

Receiving and connecting to calls

The network must establish a connection before both sides can send cells to each other. B is called virtual circuit (VC). This may be a persistent virtual circuit (PVC), which is created administratively at the endpoints, or a switched virtual circuit (SVC), created as needed by the sending parties. The creation of an SVC is driven by signaling, in which the requester specifies the receiving party's address, the type of service being requested, and any traffic parameters that may be applicable to the selected service. Network will then confirm that the requested resources are available and that a route exists for the connection.

ATM technology defines the following three levels:

• ATM adaptations (AAL);
• 2 ATM, roughly equivalent to the OSI data line level;
• physical, equivalent to a similar OSI layer.

Deployment and distribution

ATM technology has become popular among telephone companies and many computer manufacturers in the 1990s. However, even by the end of this decade, the best price and performance of Internet Protocol-based products began to compete with ATM for real-time integration and packet network traffic.

Some companies still focus on ATM products today, while others provide them as an option.

Mobile technology

Wireless technology consists of core network ATM with wireless access network. Cells here are transmitted from base stations to mobile terminals. Mobility functions are performed on an ATM switch in the core network, known as a "crossover", which is similar to an MSC (Mobile Switching Center) GSM networks. Advantage wireless communication ATM is its high throughput and high speed handover performed at layer 2.

In the early 1990s, several research laboratories were active in this area. The ATM forum was created to standardize wireless network technology. It was supported by several telecommunications companies, including NEC, Fujitsu and AT&T. Mobile ATM technology aims to provide high-speed multimedia communication technologies capable of providing mobile broadband beyond GSM and WLAN networks.

Sections of AGSV, ATM, EM boiler room, or sections of gas supply automation, heat mechanics automation, boiler room power supply.

Description of sections AGSV, ATM, ES

AGSV section decoding - gas supply automation. This section of the AGSV project was developed on the basis of a design assignment and in accordance with adjacent parts of the project and provides for the installation of a gas metering unit type SG-EKV -R-0.5-160/1.6 with an electronic volume corrector EK266/K on the gas pipeline of the boiler room, which allows you to observe instantaneous gas parameters (flow rate, pressure, temperature) and record them over a certain time.

Structurally, the electronic corrector is attached to the gas meter. The pressure sensor is built into the body of the electronic corrector. Pressure is sampled through a pulse tube connected to the meter fitting. The temperature sensor is inserted into the meter sleeve.

The cable connection of the flow meter and temperature sensor is made at the factory. The corrector is powered by two batteries supplied with the corrector. To provide uninterruptible power supply The project provides a power supply. Data from the corrector interface is transmitted via a GSM modem to the control center.

Connection of minimum and maximum gas pressure sensors and shut-off valve and control and alarm circuits for them are given in section 456-06 ATM.

This project has been developed based on the design brief and in accordance with the adjacent parts of the project. The safety of boilers and regulation of combustion processes are ensured by the boiler and burner automation, which is supplied as part of the boiler.

The ATM project provides for automatic control of raw water pumps (depending on the pressure in the return pipeline) and boiler circuit pumps (during automatic startup of the boiler). All pumps can be controlled in manual mode buttons from the boiler room control cabinet. For network pumps, network DHW pumps, raw water and DHW circulating water, an ATS is provided.

The project provides automatic switching on fans when a signal of gas contamination in the boiler room is received. If a fire occurs, the fans automatically turn off.

The boiler room provides for metering of the thermal energy of network water and hot water with a two-flow, two-channel meter of the TEM104-4 type.

The project provides for regulation of the temperature of direct network water into the heating network depending on the temperature of the outside air, as well as the temperature of hot water to the consumer using a two-channel temperature regulator type ART-01.02. Existing temperature controller and temperature sensors (installed in the heating station). It is only necessary to carry out installation in accordance with the project.

This section of EM is designed based on the design assignment and in accordance with adjacent parts of the project. According to the degree of reliability of power supply, boiler room electrical receivers belong to the 2nd category. The installed power of electrical equipment is 52.55 kW (design power and current are 30.21 kW and 62.78 A, respectively).

Electricity is supplied to the boiler room by two cables (see external networks), which are connected to the input and distribution device of the boiler room ASU, which includes an automatic transfer switch and installation of a direct connection meter.

Electricity distribution is carried out from the ASU. The power network is carried out by AVVG cable along trays and building structures. Cable runs to electrical receivers are protected at a height of up to 2.5 meters with a perforated channel.

The project provides for the implementation of working and repair lighting. The work lighting fixtures are powered from the ASU. The repair lighting is powered from a box with a step-down transformer type YaTP-0.25-220/36V and a 36V socket network. The lighting network is carried out using AVVG cable along trays, cables and building structures.

The project provides for the installation of explosion-proof luminaires of the VZG-200M type. It is switched on from outside the building. Wiring to the lamps is carried out in a pipe using PV3 wire.

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What is an abbreviation? This is a word or a whole sentence in a shortened form. In this post we will look at 10 abbreviations that we come across almost every day - in letters, in texts and even on the street.

10 common abbreviations

1. ASAP– in its full form it looks like this “ as soon as possible", which means " As soon as possible ", but since this phrase is very long, I had to shorten it as much as possible to ASAP. Let's look at examples:

• Give your reply ASAP – answer me as soon as possible
• Advise me of any changes ASAP - notify me of changes as soon as possible.

Google shortcode

2. RSVP– another encrypted message, an abbreviation of the French phrase Repondez s'il vous plaît, which translates as "Answer please". If you receive a message containing an RSVP, please know that you have been invited to participate in the event and are asking you to confirm whether you will attend.

• Please RSVP by next Saturday – please respond by next Saturday

3.RIP – rest in peace – « rest in peace " As you probably guessed, this abbreviation speaks of something sad – it can always be found on tombstones.

4. BYOB– Another riddle that can be deciphered as follows “ Bring your own beer/booze", which means " Bring your own beer and other alcoholic drinks " Suppose there is a party somewhere where there will be no alcohol, and guests can bring it with them if they wish.

• We are making a party tonight. If you want BYOB – we're throwing a party tonight. If you want, you can bring alcohol with you.
• There will be no alcohol at her birthday, so let’s BYOB - she won’t have alcohol at her birthday, so let’s take beer with us.

5. BBQ- it means barbecue – shashlik , therefore, if you are invited to a BBQ, that means you are invited to a barbecue.

• We’re having a BBQ party, you are invited - we will have a BBQ party, you are invited.

6. PIN –Personal Identity Number — personal identification number , PIN code, which is assigned to the owner of a plastic card and is necessary to establish his identity when using an ATM or when using banking services by phone.

• Please tell me your PIN number – tell me your PIN code, please
• Enter your PIN to log in – Enter your PIN to log in.

7.e.g. – exempli gratia— translated from Latin — “ For example " By the way, many people confuse it with the following abbreviation, also of Latin origin.

• Many animals lay eggs, e.g. hens, peacocks, crocodiles, penguins - many animals lay eggs, for example chickens, peacocks, crocodiles, penguins.

8.i.e. – id est– another Latin abbreviation meaning “ that is » ( those. ). When we want to explain something to someone, we add additional explanations, and this requires some kind of introductory word:

• It happened on Halloween, i.e. October 31 – this happened on Halloween, i.e. October 31.

9. etc. - et cetera is also an abbreviation of Latin origin meaning " and so on » ( etc .), and we use it when we don’t want to go into details and end the sentence with the vague “and so on.”

• I’ve bought many things at the supermarket – eggs, butter, cheese, sausage, etc. – I bought a lot of things in the supermarket – eggs, butter, cheese, sausage, etc.

10. ATM – automatic teller machine- this is a machine from which you can get money and which is located on the streets, in shops, parking lots, etc., that is, an ATM.