Comparison D-Link DGS-1016C vs D-Link DGS-1016A

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 bandwidth of a switch is the maximum amount of traffic that it can handle. Specified in gigabits per second.

This parameter directly depends on the number of network ports in the device (excluding Uplink). Actually, even if the bandwidth is not given in the specifications, it can still be calculated using the following formula: the number of ports multiplied by the bandwidth of an individual port and multiplied by two (since both incoming and outgoing traffic are taken into account). For example, a model with 8 Gigabit Ethernet connectors and 2 SFP ports will have a bandwidth of (8*1 + 2*1)*2 = 20 Gbps.

The choice for this indicator is quite obvious: you need to evaluate the expected traffic volumes in the serviced network segment and make sure that the switch's bandwidth will cover it with a margin of at least 10-15% (this will give an additional guarantee in case of emergency situations). At the same time, if you plan to often work at high, close to maximum, loads, it will not hurt to clarify such a characteristic as the internal bandwidth of the switch. It is usually given in a detailed technical description, and if this value is less than the total throughput, serious problems may arise under significant loads.

The maximum number of MAC addresses that can be stored in the Switch's memory at the same time. Specified in thousands, for example, 8K — 8K.

Recall that the MAC address is the unique address of each individual network device used in physical routing (at layer 2 of the OSI network model). Switches of all types work with such addresses. And it is worth choosing a switch according to the size of the table, taking into account the maximum number of devices that are supposed to be used with it (including based on the possible expansion of the network). If the table is not enough, the switch will overwrite new addresses over the old ones, which can noticeably slow down the work.

— 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.

— 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.

The amount of voltage required by the switch for uninterrupted operation. The power supply voltage of network equipment can vary from 5 V to 230 V, which allows you to power compatible devices from either a low-voltage USB socket on your computer or a standard household outlet. Values in the middle assume that the switch is powered by the appropriate power supply.