Comparison HP Aruba Instant On 1830-48G-4SFP vs Cisco CBS250-48T-4G

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.

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.

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.

— 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.

Recall that routing is the definition of the best path through which each data packet can be delivered to the recipient. For this, special tables are used, stored in the memory of the control network device with the routing function. According to the method of filling these tables, this procedure is divided into two main varieties — static and dynamic.

Static routing is a method in which all data routes (entries in the routing table) are manually written by the administrator; this applies both to the initial creation of the table and to making changes to it when changes are made to the network configuration. The main advantage of this method is the minimum load on the switch processor, which has a positive effect on the speed and reliability of the network. The main disadvantages of static routing are associated with the need for manual control. So, the larger the network, the more complex and time-consuming it is to manage it; Administrator's inattention can become an additional cause of failures; and diagnosing some problems is noticeably more difficult — for example, if there is a failure at the link layer, the static route remains visible as active, although no data is transmitted.

Power consumed by network equipment during operation. Knowing the indicator of energy consumption, you can, for example, calculate the battery life of equipment from an uninterruptible power supply or choose a suitable “uninterruptible power supply”.

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.