Comparison Ubiquiti UniFi Switch 24-250W vs HP J9773A v1

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.

The type of connector(s) used in the switch as an Uplink interface.

See above for details on such an interface; 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") with support for speeds up to 100 Mbit. Such a speed is considered low by modern standards, while the Uplink port puts forward increased bandwidth requirements - after all, traffic from all devices served by the switch goes through it. Therefore, in this role, Fast Ethernet ports are used mainly in inexpensive and outdated models.

- Gigabit Ethernet - LAN connector with support for speeds up to 1 Gb / s. Such a speed is often enough even for a fairly extensive network, while the connectors themselves are relatively inexpensive.

- 2.5 Gigabit Ethernet - LAN connector with support for speeds up to 2.5 Gbps.

- 10Gigabit Ethernet - LAN connector with support for speeds up to 10 Gbps. 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. Socket for fiber optic cable that supports speeds of about 1 Gb / s. At the same time, over Gigabit Ethernet, which has a similar bandwidth, this connector has one noticeable advantage - a lon...ger connection range (usually up to 550 m).

- SFP+. An evolution of the SFP standard described above. The switches usually provide a connection speed of 10 Gb / s; like the original standard, it noticeably outperforms an Ethernet connection in terms of effective range. On the other hand, the real need for such speeds does not arise very 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 Gbps.

— QSFP / QSFP+. The fastest SFPs up to 40 Gbps.

We also note 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 common. This provides versatility in connection, allowing you to use the type of cable that is most convenient 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 buying this nuance does not hurt to clarify separately.

There are also switches that use a combination of two types of SFP - SFP/SFP+; however, there are few such models and they mainly belong to the professional level.

The switch has a console port. This connector is used to control the device settings from a separate computer, which plays the role of a control panel — a console. The advantage of this format of operation is that access to the functions of the switch does not depend on the state of the network; in addition, special utilities can be used on the console that provide more extensive capabilities than a regular web interface or network protocols (see "Management"). Most often, the console port uses an RS-232 connector.

— 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.

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 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.