Power over Ethernet (PoE) is a special technology with which electrical energy is transmitted to power the device along with data via the same cable for communication with an Ethernet network.

Benefits of PoE Power

Thanks to this technology, the user no longer needs to locate the device in close proximity to a source of electrical energy and lay additional electrical wiring, which significantly expands the placement area of ​​this device and significantly reduces the costs of its installation. Thus, PoE power supply ensures a highly ergonomic work environment, taking into account the unloading of the room from additional adapters and bundles of wires, and is also economically beneficial for the customer due to the absence of unplanned costs associated with the installation of new sources of electricity.


And in fact, in rooms with big amount With multi-purpose equipment, it can be very difficult to provide electricity to each device. Mobile devices such as CCTV cameras, personal computers, wireless access points and IP phones, require installation in locations that are often far from electrical outlets and sometimes require relocation. The optimal solution This problem will be solved by a switch equipped with PoE technology, which will provide power to PoE-compatible devices.

Installation Basics

In order to install PoE power from the switch to the desired device, you need to connect a special PoE injector simultaneously to the switch port and to the source electrical supply. Often, switches of this type are produced with built-in injectors, which greatly simplifies the installation and configuration of technical equipment connected to the ports of these switches. The main advantage of the built-in PoE injector is that the switch has several PoE ports at once, and therefore this method power supply becomes possible not only for one, but for a whole range of devices.

The issue of DC power technology in PoE

There is an opinion that power direct current The power provided through PoE power is inherently less efficient than AC power due to the lower voltage. Let's look at this statement. A typical 48-port PoE switch supporting Power over Ethernet technology has a power supply ranging from 50 W to 80 W. In addition, a 740 W (IEEE 802.3af) or 1480 W (IEEE 802.3at) power supply is typically required. exclusively for PoE ports. Initially, using a long cable may seem ineffective. However, where this centralized power supply replaces multiple AC sources simultaneously, and also prevents costly human intervention (installation of electrical wiring), the power loss due to a long DC cable can be fully justified. Every year, manufacturers, guided by the most modern requirements of the high-tech market, create increasingly powerful and multifunctional switch models. Leading manufacturing companies are trademarks Cisco and Hewlett&Packard.

Cisco PoE switches

Cisco brand products occupy a leading position among customers, featuring unsurpassed advanced technical characteristics, including high performance and maximum throughput. Let's consider switches that support Cisco PoE or PoE+ standards. These are some of the Catalyst 2960, 2960-Plus, 2960-S, 2960-SF, 2960-X, 3560, 3560-E, 3560-X, 3650, 3750, 3750-E, 3750-X, 3850, and 4500 series switches. In order to determine which standard - PoE or PoE+ - a specific switch supports, you need to divide the total Aviable PoE Power supplied by the switch by the number of its ports (24 or 48). If as a result we get a value equal to 7, then the switch supports the PoE standard, and if 15.4 – PoE+. When selecting a switch, you don’t have to understand all these details, but simply contact VTK Communications, and our qualified technical specialist will help you with your choice, explain all the differences between different switches and explain all the incomprehensible points. In addition to providing power via PoE technology, such switches can offer a flexible interface, excellent protection against unauthorized network access, as well as traffic planning services. 2015-01-28T17:00:00+0300 2018-03-15T10:30:16+0300 Vladimir Afanasyev

Power over Ethernet (PoE) is a technology that allows you to transmit electrical energy along with data to a remote device via a standard twisted pair cable in an Ethernet network. To transfer power, special network switches that support this technology are used.

About switches in general

First, let's figure out what network switches are and what types they come in.

A network switch, also known as a switch (jarg switch from the English switch) is a device designed to connect several nodes of a computer network within one or more network segments.

All existing switches are different

• number of ports (2, 4, 8, 16, 24 and 48 ports, etc.)
• data transfer speed (100Mb/s, 1Gb/s and 10Gb/s, etc.)
• network layer support (network layer- layer1, layer2, layer3)
• PoE support and without it

Switches can also be divided into:

1.Unmanaged switches- These include almost all Layer 1 switches - these are simple stand-alone devices that manage data transmission independently and do not have manual control tools. Such switches are most widespread in “home” LANs and small businesses, the main advantage of which can be called low price and autonomous operation, without specialist intervention.

The disadvantages of unmanaged switches are the lack of configuration options and low internal performance. Therefore in large networks For enterprises, it is not wise to use unmanaged switches, since administering such a network is time-consuming, makes troubleshooting difficult, and imposes a number of significant limitations.

2.Managed switches mainly Layer 2 and Layer 3 are more advanced devices that also work in automatic mode, but in addition to this they have built-in control and monitoring tools.

The main disadvantage of managed switches is their higher cost compared to Layer 1, which depends on the capabilities of the device itself and its performance.

We will not give any special comments on the number of ports and data transfer speed. Now, in a little more detail, who are these levels Level1 (Layer1), Level2 (Layer 2) and Level3 (Layer 3).

Layer 1. This includes all devices that operate at layer 1 of the OSI network model - the physical layer. Such devices include repeaters, hubs and other devices that do not work with data at all, but work with signals. These devices transmit information coming from one port and relay it to all ports at once. Such devices have not been produced for a long time, and it is quite difficult to find them on the market.

Layer 2. This includes all devices that operate at layer 2 of the OSI network model - the data link layer. Such devices include all unmanaged switches and some managed ones. Level 2 switches work with data not as a continuous flow of information (like Level 1 switches), but as individual pieces of information - frames. They are able to analyze received frames and work with MAC addresses of frame sender and receiver devices. Such switches “do not understand” the IP addresses of computers; for them, all devices are named in the form of MAC addresses. Layer 2 switches create switching tables in which they correlate the MAC addresses of meeting network devices with specific ports switch.

Layer 3. This includes all devices that operate at layer 3 of the OSI network model - the network layer. Which is responsible for the mutual conversion of hardware and network addresses (MAC/IP) - the ARP protocol, finding a path between two intermediate devices, establishing a logical connection between nodes. Such devices include all routers and some managed switches, as well as all devices that can work with various network protocols: IPv4, IPv6, IPX, IPsec, etc. It is more appropriate to classify Layer 3 switches as routers, since these devices are already fully capable of routing passing traffic between different networks. Layer 3 switches fully support all the features and standards of Layer 2 switches. Network devices can be accessed using IP addresses. A layer 3 switch supports the establishment of various connections: pptp, pppoe, vpn, etc.

Smart Switch Management

There may be several options.

Telnet access to the switch console port. Configuration occurs through the command line of the switch. Telnet access is not secure.

SSH

SSH access to the managed switch is carried out using the secure SSH protocol, using various clients (putty, gSTP, etc.). Just as in the case of configuration, the configuration occurs through the command line of the switch.

Web interface

The setup is done via a WEB browser. In most cases, configuration via the Web interface does not allow you to use all the functions network equipment, which are available in full only in the mode command line.

Power-over-Ethernet

Now let’s try to figure out why these switches, which already have such wide capabilities, also include PoE.

This technology is intended for IP telephony, access points wireless networks, IP cameras and other devices to which it is undesirable or impossible to run a separate electrical cable for power supply.

PoE technology does not affect the quality of data transmission. To implement it, properties are used physical level Ethernet.

Modern 100BASE-TX Ethernet cabling consists of four pairs, two of which are unused. Free pairs are used to supply power. PoE provides power supply over standard twisted pair cable to remote devices such as wireless points access, IP phones, IP cameras, media converters, data readers, etc. Power is supplied through free twisted pairs 4-5 and 7-8, which are not used for data transmission.

802.3af PoE-A and PoE-B standards for 100 and 1000 Mbps networks. Pinout of 8-pin 8P 8C(RJ45) connector

Power sourcing equipment (PSE) differ in the way they connect power, while powered devices (splitters; powereddevice, PD) are universal. Powered devices are designed with the ability to receive power in any way, including when the polarity is reversed (for example, when a crossover cable is used).

It is important that the power supply only supplies power to the cable if the device being connected is a powered type device. Thus, equipment that does not support PoE technology and is accidentally connected to the power supply will not be damaged. The procedure for applying and disconnecting power to the cable consists of several stages.

The first step of connection detection is to determine whether the device connected at the opposite end of the cable is a powered device (PD). At this stage, the power supply unit (PSE) supplies the cable with a voltage of 2.8 to 10 V and determines the input impedance parameters of the connected device. For a powered device, this resistance ranges from 19 to 26.5 kOhm with a parallel connected capacitor with a capacity of 0 to 150 nF. Only after checking the compliance of the input resistance parameters for the powered device, the power supply device proceeds to the next stage, otherwise the power supply device again, after a time interval of at least 2 ms, tries to determine the connection.

After the first step of determining the connection, the power supply can further perform a classification step, determining the range of power consumed by the powered device in order to then control that power. Each powered device, depending on the declared power consumption, will be assigned a class from 0 to 4. The minimum power range is class 0. Class 4 is reserved by the standard for further development. Classification is performed by introducing a voltage from 14.5 to 20.5 V into the cable by the power supply device and measuring the current in the line.

After passing through the identification and classification stages, the power supply supplies the cable with a voltage of 48 V with a rising edge no faster than 400 ms. After applying full voltage to the powered device, the power supply monitors its operation in two ways:

1) if the powered device consumes less than 5 mA of current within 400 ms, then the power device removes power from the cable;

2) the power supply supplies the cable with a voltage of 1.9-5.0 V with a frequency of 500 Hz and calculates the input resistance; if this resistance is greater than 1980 kOhm for 400 ms, the power supply removes power from the cable. In addition, the power supply continuously monitors the overload current. If the powered device draws more than 400 mA current for 75 ms, the power supply will remove power from the cable. When the power supply detects that the powered device is disconnected from the cable or that the current consumption of the powered device is overloaded, the power supply is removed from the cable for a period of at least 500 ms.

IN this moment Two PoE standards are used: IEEE 802.3af PoE Standard and IEEE 802.3at-2009 Standard, also known as PoE Plus. Below is a table of two PoE standards and their classes for Ethernet cable type.

Standard	PoEIEEE 802.3af	PoE Plus IEEE 802.3at
Cable Requirements	Category 3 (UTP CAT3) or higher	Type 1: Category 3 (UTP CAT3) or higher
		Type 2: Category 5 (UTP CAT5) or higher
Current strength	0.35 A	Type 1: 0.35 A
		Type 2: 0.6 A
Injector output voltage	44 - 57 V	Type 1: 44 - 57 V
		Type 2: 50 - 57 V
Powered Device Input Voltage	37 - 57 V	Type 1: 37 - 57 V
		Type 2: 42.5 - 57 V
Maximum power consumption of the powered device	PoE class 0, 3: 12.95 W	Type 1: PoE Class 0, 3: 12.95 W
	POE Class 1: 3.84 W	PoE Class 1: 3.84 W
	PoE Class 2: 6.49 W	PoE Class 2: 6.49 W
	PoE Class 4: not used	Type 2: PoE Class 4:
Supported Powered Devices	IP cameras, IP phones, access points	All PoE devices, outdoor PTZ cameras,
		WiMAX access points, LED displays, some computers

Despite all the advantages of using PoE technology standardized according to 802.3af, there are also disadvantages, for example:

• high additional cost devices with PoE function (802.3af);
• High power consumption of PoE switches compared to conventional ones.

Therefore, alternative solutions called "PassivePoE" are released in the form of an intermediate set of adapters that can only support electrical characteristics compliance with the 802.3af standard, (that is, the Passive PoE injector will transmit any voltage that is supplied by the power supply, not necessarily 48 V) but not protocol ones. Passive PoE is not fully compliant with the IEEE 802.3af standard.

Typically, a Passive PoE (PPoE) kit does not include a power supply because... It is assumed that the power supply supplied with the powered device is used. Maximum length cable when using a Passive PoE injector is significantly less than when using a PoE injector (30-60 meters, not 100 meters). Of course, this largely depends on the parameters of the standard power supply, the current consumed by the device and losses in the cable. To compensate for these losses by long distance It is enough to replace the standard power supply with a more powerful one, with a voltage from 12 to 48 volts.

The passive PPoE-Light kit consists of two adapters: an Injector (INJECTOR) and a Splitter (SPLITTER). Passive PoE is effective for use in existing network infrastructure, allowing the use of PoE technology for devices that are not equipped with this function natively. The PPoE kit does not include any power supply unit (PSU), since it is assumed that in most cases you can use the standard PSU included with the device. PPoE provides power supply via standard twisted pair cable to remote devices such as wireless access points, IP phones, IP cameras, etc. Power is supplied in the same way as in classic PoE over free twisted pairs 4-5 and 7-8, which are not used for data transfer.

Let's look at a small example of how to calculate the use of PoE in a combination of Yealink SIP-T48G phones supporting PoE (Power over Ethernet, 802.3af) Class 0 with a power consumption of 2.4-10.5W and switches Huawei Quidway S5700-28C-PWR-EI 24 ports.

The S5700 PWR switches comply with IEEE 802.3af and 802.3at (PoE+) standards. And they can provide ports with a maximum load of up to 30W. In our case, the S5700-28C-PWR-EI has a power supply installed with a power of 500W and output for PoE369.6W. According to the 802.3af standard, we can power 24 ports from it with a load of 15.4 W per port, or according to the 802.3at standard, 12 ports with a load of 30 W.

Having carried out simple mathematical calculations we get:

10 phones at 10.5 W = 105 W in total, which is less than the maximum output for PoE369.6W.

It turns out that we can connect 24 Yealink SIP-T48G phones to the Huawei Quidway S5700-28C-PWR-EI switch via PoE. Or other equipment with 12 ports according to the 802.3at (PoE+) standard with a power of up to 30W, for example, HP t410AiO thin clients supporting the 802.3at (PoE+) standard with a power consumption of 24W 12 pieces.

Or combine various equipment, a video camera with Grandstream GXV3674_HD_VF with support for PoE IEEE802.3af, video intercom ROBIN SV 130 with support for PoE IEEE802.3af, etc. You can create quite a few different combinations of using PoE equipment.

Conclusion

There is quite a lot of controversy regarding the feasibility of PoE. The most common argument (in terms of power supply for IP phones) - we will supply for each workplace additional Pilot for 300 rub. and everything will work much cheaper. So, 300 rub. roughly we spend on each workplace (24 in total) = 7200 rubles. (about 110 USD)

Now let’s transfer this to switches and money:

• Huawei S2700-26TP-EI-AC - 24 ports without PoE - 441 USD

Huawei S2700-26TP-PWR-EI - 24 ports with PoE - 563 USD

The difference is 122 USD versus savings on “pilots” - 110 USD. Doubtful, isn't it?

Savings in terms of energy consumption in our realities are most likely a questionable thing. Better positioning this technology as an additional convenience and a unique solution to the aesthetic issue with a bunch of wires under the table.

When choosing a switch for the office, we chose the model with PoE.

PoE (Power over Ethernet) switch is a switch that uses the technology of transmitting data and power over the same wires, using twisted pair. Switches are necessary to connect several nodes of a computer network.

This is what a POE switch looks like, it is also called a switch (switch)

Computers are connected using an Ethernet cable to a switch. This device can receive and transmit data, determining its source and recipient and transmitting packets of information only to those nodes on the network for which they are intended. For this purpose, switches use switching tables— schemes for matching the MAC address of a computer on the network to a switch port. The switch that was just turned on has an empty table. When transmitting data over the network, it analyzes the MAC addresses of the sending device and enters them into a table located in associative memory. If the device then receives data assigned to a computer whose MAC address is in the table, the switch will send a signal only through the port associated with this node. The advantages of switches are high speed their work, unlike concentrators.

Using switches for video surveillance

Network video surveillance is used to organize video surveillance through the use of computer networks, allowing you to transfer data anywhere in the world.

The visual signal is recorded using IP cameras that transmit digitized data over networks using the IP protocol. Switches provide additional functionality for surveillance systems. Several cameras of a video surveillance system can be connected to a switch, which distributes digital data streams between output devices: computers, video servers, monitors, etc.

The most modern systems video surveillance uses managed switches that have an interface for setting the behavior of devices depending on the signals received by them, transmitting information in the event of alarm sensors triggering to certain network nodes, etc.

PoE technology and video switches

Recently, technology has become widely used to organize digital video surveillance systems.

Benefits of PoE:

• Simplification of the electrical system: absence of a large number of power cables stretched to all devices.
• Security: PoE switches convert 220V into the voltage needed to power cameras, usually 12V.
• Increasing the range to the powered device.
• Ability to shut down/reboot devices in the system remotely.
• Possibility of extensive management of devices on the network.

Video cameras that support PoE can be powered via an Ethernet cable. Video surveillance switch included in electrical network, converts alternating current at constant required power. The same function can be performed by a PoE injector connected to a switch or directly to an outlet.

PoE injector circuit

A typical POE injector: a connector for connecting a power supply, a connector for connecting a LAN line and for transmitting a signal to a camera, already powered by POE

A typical injector has two ports: a device supporting the technology is connected to POE, and a computer/switch/router is connected to LAN.

Connection diagram of the injector to the system

The figure above shows that one switch, depending on the number of ports, can include several devices powered by Power over Ethernet technology. For equipment that does not support PoE, you can use splitters that convert the Ethernet signal into a digital data stream and an electrical power supply component.

Popular models of PoE video switches

Sigrand

The company produces products for video surveillance systems: IP cameras, switches (including with PoE), PoE floodlights, etc. In the SG-1 series, models have 6 Ethernet ports and provide power up to 60 V. The interesting thing about Sigrand’s equipment is that that the equipment can be connected in series in one line. This saves money and reduces the cost of consumables.

Diagram of building a network based on Sigrand equipment

Appearance of Sigrand POE switch

Building and testing the network before installation

Raisecom

The brand provides a wide selection of various equipment and switches that can be used in video surveillance systems. ISCOM series switches are distinguished by a large number of ports and the possibility of remote management.

RAISCOM equipment can be integrated in different ways

Cisco

The company has a large selection of switches that can be used in industry. The devices are compact in size, energy efficient, and programmable. A well-thought-out API is used for programming. Cisco is a fairly common brand whose catalog includes high-quality equipment for industrial use. The company's quality is greatly inflated, and the price, as you know, always depends on this indicator.

There are many different other brands that are no worse or better (depending on how you look). It is better to make a choice according to technical specifications, appearance, installation method and location, as well as price. I would also recommend using reviews.

In the next article we will talk about POE injectors: how they differ from POE switches, what are the advantages and disadvantages.

Video cameras and video recorders connected to various network switches with and without POE, routers, have firmly established themselves in the video surveillance systems market. About the widespread transition to digital equipment It’s too early to say. However, the trend towards consistent market conquest and displacement of coordinate matrix structures has been visible over the past five years.

In the relevant trade industry, manufacturing companies have appeared that specialize only in video surveillance devices operating via the Internet. In turn, the demand for specialized equipment to create stable functioning of the system has increased.

You can often come across the point of view that IP video surveillance devices connected to world wide web, can be connected to an organization’s already functioning network, which guarantees savings on installation costs. However, in practice, work efficiency similar system is not different high quality. Typical network devices cannot cope with the increased load on them. As a result, problems arise not only in the functioning of video surveillance devices, but also in the entire enterprise network.

For this reason, you should focus on network switches for video surveillance systems, since these devices bear the main burden of redirecting an array of information.

Video surveillance switch - what is it?

Internet Protocol video surveillance structures often use standard network switches, better known as switches. They are also called switches (from the English “switch”). Such devices create an association of connecting elements of the local network. During operation, the switch analyzes the MAC addresses of all connected equipment and creates a special input correspondence table, which makes it possible to limit the transfer of information to the local network.

In the course of developing the structure of video monitoring connected to the Internet, attention is focused on the combination of technical parameters of the switch, mounted video surveillance devices and general requirements for the functioning of the system.

Switch Bandwidth

Each network switch for video surveillance is equipped with certain information processing capabilities. In other words, this is the real amount of information that devices are capable of processing in a given period of time. In addition, the processing capability of each connector is also taken into account. The most common indicators are ten - one hundred megabits per second and one gigabit per second.

It must be kept in mind that often the total processing capacity of a switch may be less than the combined value of all inputs. If such a device is installed in full, then the structure is not able to function in proper quality. In particular, the user will experience slow video recording. In addition, the signal will drop out from time to time.

Number of LAN ports

This switch characteristic reflects the maximum number of connected video surveillance devices or other network components. For home video monitoring, switches with a small number of inputs (from 4) are often used. For specialized structures, equipment with eight, sixteen or twenty-four connectors is used. Taking into account the number of inputs, it is necessary to keep in mind the compatibility of the overall ability to process information per unit of time.

Degree of protection

As well as video surveillance devices with Internet Protocol, switches can be developed for external (street) and internal networks video control. Switches for outdoor use must guarantee operation regardless of weather conditions. For this reason, devices are manufactured in reinforced shells with a protection level of at least IP66.

For structures installed inside buildings, switches for video tracking devices in ordinary production are used. Portable devices that can be mounted on a DIN rail are common. But they are characterized by a small number of connectors.

Switch with Power over Ethernet technology

The presence of Power over Ethernet greatly simplifies the installation of a video control structure, since power is routed through a regular network cable (). It should be noted that a switch with POE is used together with video surveillance devices that support this option (this is necessarily reflected in the technical parameters).

Specifics of switches with Power over Ethernet

PoE is a technology for organizations information channel together with power supply for IP video cameras using a regular Ethernet connection. Taking into account the difficulty of installing IP video control structures, power supply and image transmission over a single wire are the most the best option. For this reason, experienced users often give priority to devices with Power over Ethernet.

The maximum distance for transmitting a video signal from an IP video camera over twisted pair cable without the use of additional devices is 100 meters. It is worth noting that it is necessary to power the camera at such a distance directly next to the video camera. The POE switch allows you to transmit both signal and voltage over one cable over a distance of up to 150 meters.

A POE switch is an excellent solution in the field of IP video surveillance in 99% of cases, with the exception (that same 1%) when, for example, current cameras with panning, zooming and Ptz control with a power of approximately ninety watts are not able to function without laying an extra power cable, i.e. .To. the usual twenty-five watts of Power over Ethernet switch is definitely not enough.

But in last years Manufacturers create profile solutions with increased power, which makes it possible to use quite powerful video monitoring devices with, as well as power additional devices(such as infrared illuminators). But you shouldn't rely on them too much. In any situation, it is necessary to carefully calculate the power consumed by the structure, correlating it with the capabilities of the switch.

UPLINK

A switch with poe not only has a certain number of Power over Ethernet ports, but also an uplink port thanks to which the device can be combined with various network components: routers, computers, DVRs, etc.

On video: Selecting a switch for video surveillance

All commercially available switches are divided into Fast Ethernet and Gigabit Ethernet. A parameter that is required to be taken into account when selecting. This is the bandwidth characteristic: Fast Ethernet - 10/100 Mbit/s, Gigabit Ethernet - 10/100/1000 Mbit/s.

Symmetrical and asymmetrical switches

Symmetry and asymmetry characterize a network switch based on the bandwidth of each port. A symmetric switch connects ports with the same bandwidth - 10 Mbps, 100 Mbps or 1000 Mbps. An asymmetric switch connects ports with different bandwidths - 10 Mbit/s with 100 Mbit/s, 100 Mbit/s with 1000 Mbit/s. Such devices are used when there are large client-server network flows: users simultaneously exchange data with the server, and this requires wide bandwidth for the port. When forwarding traffic from a 100 Mbps port to a 10 Mbps port, the switch uses a memory buffer to avoid congestion. Memory buffer size is an important selection criterion.

Unmanaged and managed PoE switches

An unmanaged switch is easier to use - ready to install out of the box, it does not need to be configured. Ideal for typical systems. Available on a managed switch fine tuning many parameters. The devices are designed to solve complex problems and build extensive large systems that include equipment with different technical characteristics. A modern PoE switch is a full-fledged element of a comprehensive security system.

The very name “PoE switch” indicates that the device performs communication tasks and distributes energy at the same time. But connecting several nodes to a network and powering devices over twisted pair cables are not all the functions. PoE switches are not inferior in functionality to network switches, on board:

• Configuring the bandwidth of each port.
• Reserving bandwidth for applications.
• Traffic prioritization.
• Static routing.
• Network storm protection.
• Port mirroring.
• Aggregation.
• Supports SSL and SSH encryption.
• Detection of loops in the network with further port isolation and cable diagnostics.
• Quantitative limitation of the studied mac addresses.
• Access list and the like.

The indicated functions are mostly present in unmanaged models, but they do not have the ability to customize (it is not always needed - it depends on the tasks).

Voltage

At the output, the PoE switch produces 48 V. The voltage of the powered device is 12 V. This is due to inevitable electrical losses when transmitting over long cables. Thus, the required amount of energy reaches the energy consumers, which would not happen if the output of the switch was 12 V. When the distance between devices is small, losses are minimal. In such a case, each end device is equipped with a converter that adapts the voltage level, and there are switches on sale that operate in several modes.

Number of ports

The number of ports is an ambiguous characteristic. 4-port, 8-port, 16-port, 24-port are common names that do not indicate the number of connectors with PoE support. When you need to connect 8 video surveillance cameras to the switch, you need 8 PoE ports, but in fact there are at least one more ports: in addition to RJ-45 with PoE, there is also Ethernet without PoE support, SFP, and combined ones. When buying a switch, keep in mind that for 4 devices you need exactly 4 PoE ports, for 16 - 16. 4, 8, 24, 48 are the international standard. 16 ports are a Russian invention. Manufacturers focused on solving customer problems produce switches with 2, 5, 6, 7, 9, 10 or more ports with PoE support.

PoE budget

The PoE budget is a characteristic of each port and their combination. Please note: the budget of each port individually is higher than the budget of the same port, but maximum load(using all connectors). Example: a port with a budget of 15 W, a total of 8 ports, a total budget of 100 W. If there is overconsumption, energy is not supplied to one of the ports - according to the specified (manual or manufacturer) priority. When buying a PoE switch, you should consider your overall PoE budget.

You can buy PoE switches from Netis, Osnovo, TP-Link, Hikvision, Trassir, Hikvision. Trassir products are produced by us, the rest are produced by partners. Netis, Osnovo, TP-Link, Hikvision are on sale at manufacturer prices.