Comparison Dahua DH-PFS3110-8P-96 vs Cisco SG110D-08HP

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.

The number of standard RJ-45 network connectors in the Fast Ethernet format provided in the design of the switch.

Fast Ethernet is the most modest of the wired connection formats over a twisted-pair network cable nowadays — it provides data transfer rates up to 100 Mbps. However, even this speed is often enough for relatively simple tasks that are not associated with large amounts of data. Therefore, this interface is still widely used in modern switches.

As for the number of connectors, it corresponds to the number of network devices that can be connected to the "switch" directly, without the use of additional equipment. In the case of Fast Ethernet, the number of connectors up to 10 inclusive is considered relatively small, from 10 to 25 — average, and the presence of more than 25 ports of this type is typical for professional-level models.

The number of standard Gigabit Ethernet RJ-45 network connectors provided in the design of the switch.

As the name suggests, these connectors provide data transfer rates up to 1 Gbps. Initially, Gigabit Ethernet was considered a professional standard, and even now the real needs for such speeds arise mainly when performing special tasks. Nevertheless, even relatively inexpensive computers are now equipped with gigabit network adapters, not to mention more advanced technology.

As for the number of connectors, it corresponds to the number of network devices that can be connected to the "switch" directly, without the use of additional equipment. In the case of Gigabit Ethernet, the number of connectors up to 10 inclusive is considered relatively small, from 10 to 25 — average, and the presence of more than 25 ports of this type is typical for professional-level models. At the same time, it is worth noting that in some "switches" individual connectors of this type are combined with optical SFP or SFP + (see below). Such connectors are marked "combo" and are taken into account both in the RJ-45 count and in the SFP/SFP+ count.

The number of optical network ports of the SFP standard provided in the design of the switch. We emphasize that we are talking about "ordinary" SFPs; SFP+ data is usually listed separately.

Specifically, in switches, the marking “SFP” usually means a connector for fiber with a connection speed of 1 Gbps. Technically, this is not much compared to RJ-45 speeds; however, this connection format has a number of advantages. One of the main ones is a greater effective range: the mentioned gigabit standard used in switches works with a cable length of up to 550 m, and by the standards of fiber, this is still very little. True, the cable itself is sensitive to kinks and requires quite delicate handling; on the other hand, it is completely immune to electromagnetic interference. On the other hand, in general, the SFP format is noticeably less popular in network equipment than RJ-45; therefore, there are few ports of this type even in advanced devices. So, solutions for 2 or 4 SFP connectors are most widely used, although there are more - 6, 8, or even 10 or more. It is also worth considering that the so-called combo connectors can be used in switches, combining SFP and RJ-45; the presence of such ports is specified in the notes, they are taken into account both in the calculation of RJ-45 and in the calculation of SFP.

To clarify, Uplink inputs also often use this type of connector; however, their...number is specified separately (see below).

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.

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.

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.

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.

The range of operating temperatures allowed for the switch, in other words, the air temperature at which the device is guaranteed to remain operational.

All modern switches are able to normally endure conditions that are comfortable for a person. Therefore, you should pay attention to this indicator, first of all, in cases where the conditions at the installation site of the switch will differ markedly from home / office; a typical example is the placement of ISP equipment in the attic of a multi-storey building. At the same time, special attention should be paid to the lower limit of the temperature range — not every device is able to operate at sub-zero temperatures. If we talk about specific numbers, then for an unheated room frost resistance is desirable at least at the level of -5 °C, and ideally — — 20 °C(although, of course, this also depends on the climate).

Also note that, in addition to temperature, most switches have restrictions on the relative humidity of the air; these restrictions are usually specified in the documentation.