Type
—
Unmanaged. The simplest kind of switch that does not have, as the name suggests, the ability to manage; and the possibilities of monitoring the state of the device are usually limited to the simplest indicators in the form of light bulbs (power supply, port activity). The advantages of such models are battery life, ease of use and low cost. The main disadvantage of this type is obvious — the impossibility of configuring the operation parameters. Unmanaged switches are well suited for small LANs like a home or small office where little administration tricks are required; but for large organizations they should not be used.
—
Customizable. This category includes switches that allow you to change some of the operating parameters. At the same time, the possibilities for such changes are much narrower than in managed models, and the matter is usually limited to disabling individual ports, switching standard speeds for Ethernet connectors (for example, from 100 Mbps to 10 Mbps) and simple monitoring tools like browsing the network statistics. In addition, after reconfiguration, the device, usually, needs to be rebooted — in other words, it is impossible to control the operation of the switch on the fly. However, professional models designed for large networks can also belong to this type.
—
Managed 2 levels. The term "managed" means that the switch has the ab
...ility to reconfigure "on the fly" — in contrast to the configurable models described above. In addition, the overall functionality of such devices in most cases is noticeably wider. And "layer 2" means that the device supports only the second layer of the OSI network model — the channel, which is responsible for physical addressing. In fact, this means that the switch is able to work with the MAC addresses of connected devices, but IP addressing is beyond its capabilities.
— Managed 3 levels. A kind of managed switches (see above) that supports the third level of the OSI network model. This layer is responsible for logical addressing and route definition, which allows the device to work with IP addresses. Due to this, models of this type are considered the most advanced, they often provide not only the traditional features for "switches", but also individual functions of routers. On the other hand, the abundance of features significantly affects the price. These switches are commonly used in data centers, telecommunications companies, and other professional networking environments; it hardly makes sense to purchase such a device for a home or small office.Mount
The form factor determines how the switch is installed.
—
Desktop. Devices designed to be placed on a flat surface such as a countertop or shelf; some models also allow hanging on the wall. Significantly easier to install than rack or DIN rail equipment (see below), but most desktop switches are entry-level, maximum mid-range. This is because desktop placement is less secure than rack or rail mounting, making it less suitable for professional equipment.
—
Rack mounted. Switches designed for installation in a telecommunications rack. To do this, the design provides for an appropriate set of fasteners, and the body is made in a standard size. This size is quite large, which allows for numerous network ports; and the rack mounting itself is reliable. Therefore, this option is used by most professional-level switches, although there are also relatively simple models with this installation method.
—
Mounted on a DIN rail. Switches mounted on a standard DIN rail. Such rails are used as mounting fixtures, in particular, on electrical panels and in cabinets for special equipment, however, if desired, they can be fixed to any vertical surface, including a regular wall. Specifically, "switches" with a similar installation, as well as rack-mounted ones, are mainly of a professional level; however, rail-mounted models are much smaller, resulting in more m
...odest functionality and fewer ports. Also note that they are usually executed in a vertical rather than a horizontal layout.
— Street (on the mast). Switches that can be installed outdoors. A characteristic feature of such equipment is the enhanced protection of the case, which protects the internal components from dust, moisture, high and low temperatures, etc. winter application (if you need a frost-resistant model, you can use the "Operating temperature" list below). However, if the equipment needs to be placed on the street (or in a room where the conditions are not very different from the street ones), then it is definitely worth choosing from this category.Control
Management methods and protocols supported by the switch.
—
SSH. Abbreviation for Secure Shell, i.e. "Safe shell". The SSH protocol provides a fairly high degree of security, because. encrypts all transmitted data, including passwords. Suitable for managing almost all major network protocols, but requires a special utility on the host computer.
—
Telnet. A network management protocol that provides configuration using a text-based command line. It does not use encryption and does not protect transmitted data, and is also devoid of a graphical interface, which is why in many areas it has been supplanted by more secure (SSH) or more convenient (web interface) options. However, it is still used in modern network equipment.
—
Web interface. This function allows you to open the management interface of the switch in a common Internet browser. The main convenience of the web interface is that it does not require additional software — a browser is enough (and it is available in any "self-respecting" modern OS). Thus, knowing the device address, login and password, you can manage the settings from almost any computer on the network (unless, of course, otherwise specified in the access parameters).
—
SNMP. Abbreviation for Simple Network Management Protocol, i.e. "simple network control protocol". It is a stan
...dard part of the common TCP/IP protocol on which both the Internet and many local networks are built. It uses two types of software — "managers" on control computers and "agents" on managed computers (in this case, on a router). The degree of security is relatively low, but SNMP can be used for simple management tasks.
Note that this list is not exhaustive — modern switches may provide other management options, for example, support for proprietary utilities and special technologies from the same manufacturer.Basic features
—
DHCP server. A feature that makes it easy to manage the IP addresses of devices connected to the switch. Without its own IP address, the correct operation of the network device is impossible; and DHCP support allows you to assign these addresses both manually and fully automatically. At the same time, the administrator can set additional parameters for the automatic mode (range of addresses, maximum time for using one address). And even in fully manual mode, work with addresses is performed only by means of the switch itself (whereas without DHCP, these parameters would also have to be specified in the settings of each device on the network).
—
Stacking support. The ability to operate the device in stack mode. A stack consists of several switches that are perceived by the network as one “switch”, with one MAC address, one IP address, and with a total number of connectors equal to the total number of ports in all involved devices. This feature is useful if you want to build an extensive network that lacks the capabilities of a single switch, but do not want to complicate the topology.
—
Link Aggregation. Switch support for link aggregation technology. This technology allows you to combine several parallel physical communication channels into one logical one, which increases the speed and reliability of the connection. Simply put, a switch with such a fun
...ction can be connected to another device (for example, a router) not with one cable, but with two or even more at once. The increase in speed in this case occurs due to the summation of the throughput of all physical channels; however, the total speed may be less than the sum of the speeds — on the other hand, combining several relatively slow connectors is often cheaper than using equipment with a more advanced single interface. And the increase in reliability is carried out, firstly, by distributing the total load over individual physical channels, and secondly, by means of "hot" redundancy: the failure of one port or cable can reduce the speed, but does not lead to a complete disconnection, and when the channel is restored, the channel is switched on automatically.
Note that both the standard LACP protocol and non-standard proprietary technologies can be used for Link Aggregation (the latter is typical, for example, for Cisco switches). In addition, there are quite a few alternative names for this technology — port trunking, link bundling, etc.; sometimes the difference is only in the name, sometimes there are technical nuances. All these details should be clarified separately.
— VLAN. Support of the VLAN function by the switch — virtual local area networks. In this case, the meaning of this function is the ability to create separate logical (virtual) local networks within the physical "local area". Thus, it is possible, for example, to separate departments in a large organization, creating for each of them its own local network. The organization of VLAN allows you to reduce the load on network equipment, as well as increase the degree of data protection.
— Protection against loops. The switch has a loop protection function. The loop in this case can be described as a situation where the same signal is launched in the network in an endless loop. This may be due to incorrect cable connection, the use of redundant links and some other reasons, but anyway, such a phenomenon can “put down” the network, which means it is highly undesirable. Security prevents loops, usually by disabling looped ports.
— Limiting the speed of access. The ability to limit the data exchange rate for individual switch ports. Thus, it is possible to reduce the load on the network and prevent the "clogging" of the channel by individual terminals.
Note that the matter is not limited to this list: other features may be found in modern switches.PoE (output)
The switch supports
the Power over Ethernet function.
This feature allows the switch to supply power to network devices over the same Ethernet cable that transmits data. This reduces the number of wires and simplifies power supply, which is especially convenient if the device is installed in a hard-to-reach place where there is no outlet nearby, and it is difficult to pull an additional cable. An example is an IP surveillance camera installed under the ceiling.
The number of PoE outputs may vary. It should also be borne in mind that when several consumers are connected at the same time, specific power restrictions apply; see "Total PoE Power" for details.
Accordingly, such devices are much more expensive than
switches without PoE.
PoE outputs
The number of PoE-enabled outputs (see above) provided in the design of the switch. This number corresponds to the maximum number of PoE network devices that can be connected to this model at the same time.
PoE output power
The PoE power (see above) provided by the switch to each individual PoE output. This indicator allows you to evaluate whether a particular device can be connected to such an output — the power consumption of the load in peak mode should not exceed the output power of the port. There are three standards EEE 802.3af (
PoE, ~15W), IEEE 802.3at (
PoE+, ~30W) and IEEE 802.3bt (
PoE++, ≥40W)
Note that when connecting several PoE devices at the same time, the total PoE power must also be taken into account — see below for more details.
Total PoE power
The total output power provided by the switch when powering devices using the PoE standard (see above).
This indicator usually corresponds to the sum of the powers of all outputs — that is, the power of one PoE port, multiplied by their total number. However, the power limits for one output and for the entire switch are somewhat different: if a load with a power equal to the output power of the power supply on this connector can be connected to a single connector, then the total power consumption of all devices connected via PoE should ideally not exceed 75% of the total power supply — this gives an additional guarantee in case of malfunctions. In fact, this means that all PoE outputs cannot be used “to the fullest” at the same time. For example, if there are two such outputs, and one is loaded at 100%, then the second can be loaded with a maximum of 50% — the total power consumption in this case will be the same 75% of the total output. Therefore,
a large total power is needed when using the device to the maximum.
PSU
— Built-in.
The built-in power supply does not take up space on the outside, but can significantly increase the size and weight of the entire switch. Because of this, this option is quite rare — mainly among rack-mount models (see "Form factor"), where an external unit can create significant inconvenience, as well as among the most powerful desktop switches, for which restrictions on dimensions and weight is not critical.
— External. Theoretically
, an external power supply requires additional space, and therefore is not as convenient as an internal one. In fact, most blocks of this type are quite compact in size and are equipped with “plugs” for sockets right on the case — in other words, the block is installed on a socket, and from there the wire stretches to the switch. And the absence of power circuits and transformers inside the case has a positive effect on compactness. Thanks to all this, this option is very popular among desktop models (see "Form factor"), primarily entry-level and mid-level.
— No BP. The absence of a power supply both in the design and in the delivery set is a rather rare case found in three types of switches. The first variety is models that use PoE power (see above) and do not require separate power sources. PoE power is relatively small, so relatively simple devices with a small number of ports fall into this category. The second variety is professional switc
...hes, the power supplies for which are sold as separately installed internal modules; such equipment may even provide the possibility of using two PSUs simultaneously (main and backup) and hot-swapping them. The third type — switches with installation on a DIN rail (see "Form factor") and having terminals for connecting a specialized external power source.