Fast Ethernet
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.
Gigabit Ethernet
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.
Uplink
The number of Uplink connectors provided in the design of the switch.
“Uplink” in this case is not a type, but a connector specialization: this is the name of the network interface through which the switch (and network devices connected to it) communicate with external networks (including the Internet) or network segments. In other words, this is a kind of "gate" through which all traffic from the network segment served by the switch is transmitted further. Uplink, in particular, can be used to connect to a similar "switch" (for horizontal network expansion) or to a higher level device (like a core switch).
Accordingly, the number of Uplink connectors is the maximum number of external connections that the switch can provide without using additional equipment. The specific type of such a connector may be different, but this is usually one of the varieties of LAN or SFP; see "Uplink type" for details.
Uplink type
The type of connector(s) used as the Uplink interface on the switch.
For more information about such an interface, see above; Here we note that the same network ports are usually used as Uplink as for connecting individual devices to the switch. Here are the main options for such connectors:
— Fast Ethernet — LAN network connector (for twisted pair cables) supporting speeds up to 100 Mbit/s. This speed is considered low by modern standards, while the Uplink port places increased demands on throughput - after all, traffic from all devices served by the switch passes through it. Therefore, in this role, Fast Ethernet ports are used mainly in inexpensive and outdated models.
— Gigabit Ethernet — LAN connector supporting speeds up to 1 Gbit/s. This speed is often sufficient even for a fairly extensive network, while the connectors themselves are relatively inexpensive.
— 2.5 Gigabit Ethernet — LAN connector supporting speeds up to 2.5 Gbit/s.
— 10Gigabit Ethernet — LAN connector supporting speeds up to 10 Gbit/s. Such features allow you to work comfortably even with very large volumes of traffic, but they significantly affect the price of the switch. Therefore, this option is rare, mainly in high-end models.
— SFP. A connector for a fiber optic cable that supports speeds of about 1 Gbit/s. At the same time, over Gigabit Ethernet, which has a similar throughput, this connector has one noticeable advantage - a...longer connection range (usually up to 550 m).
- SFP+. Development of the SFP standard described above. Switches usually provide a connection speed of 10 Gbit/s; like the original standard, it noticeably exceeds the effective range of an Ethernet connection. On the other hand, the real need for such speeds does not arise so often, and SFP+ is quite expensive. Therefore, the presence of such Uplink connectors is typical mainly for high-end models with a large number of ports.
- SFP28. Another development of SFP with increased throughput up to 25 Gbit/s.
- QSFP / QSFP+. The fastest SFPs up to 40 Gbit/s.
Note also that the connectors described above (except perhaps Fast Ethernet) are rarely used as the only type of Uplink input. Combinations of electrical and fiber optic ports—SFP/Gigabit Ethernet and SFP+/10Gigabit Ethernet—have become noticeably more widespread. This provides versatility in connection, allowing you to use the most convenient type of cable in a given situation; and if necessary, of course, you can use all Uplink inputs at once. However, it is worth considering that in some models, Ethernet and SFP interfaces can be combined in one physical connector. So before purchasing, it doesn’t hurt to clarify this nuance separately.
There are also switches that use a combination of two types of SFP - SFP/SFP+; however, there are few such models and they are mainly of the professional level.
Basic features
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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.
