Gigabit Switches: Tips for Choosing

Modernization of the local network of enterprise computers is a task that all system administrators face sooner or later. Improved interaction of computers with each other will create optimal conditions for the work of employees and in the future will lead to an increase in the company's success. The main device, the heart of any developed local network are gigabit switches. They provide uninterrupted multi-stream and high-speed data transmission and signal branching. From the correct choice of this element depends the functioning of the network and the entire enterprise as a whole.

Switch and Hub

Switch - a device that provides the integration of several computers into a single local network and serves to improve the quality of the transmitted signal. Exactly the same functions are performed by other network equipment - the hub (with the English Hub - the node of any network). However, when choosing experts for a long time recommend giving preference to the switches. What is the reason for this?

The work of the hub can be compared with the operation of a conventional repeater - it receives a signal and forwards it to all connected computers, regardless of which PC the information stream was intended for. As a result of such a "mass mailing", the local network quickly "hammered", the transmission rate as a whole decreased. In addition, the more hubs you installed in the network, the higher the probability of a packet storm - a situation where a large number of parasitic packets were sent over the network.

Ordinary and gigabit switches immediately after the connection are no different from the hub. However, over time, they form a switching table, or an ordered list of MAC addresses of computers, according to which in the future packet data is sent. Thus, optimal network functionality is supported.

Number of ports and speed

LAN performance depends on the parameters of the switch. Even the cheapest devices have a large set of functions that distinguish them among other representatives of this price category. However, when choosing one should pay attention to only a few of the most important parameters. The first is the number of ports. It determines the number of network devices that can be connected to the switch. Usually the number of ports varies from 5 to 48. Another important parameter is the data transfer rate - the speed at which each gigabit port on the switch functions. In our case, this is not less than 1000 Mb / sec. But most of the time the equipment supports the IEEE 802.3 Nway standard - auto-detection of packet transmission speed.

Throughput

Bandwidth is the product of the number of ports per maximum data rate. This parameter determines the system performance at the peak load moment. It is optimal if this indicator is higher than the data stream transmitted from all PCs simultaneously. For example, your switch has 10 ports at speeds up to 300 MB / s. Its bandwidth is 2 Gb / s. During maximum load, the ports will be able to transmit the information stream equal to 3 Gb / s, which is lower than the bandwidth. Such gigabit switches will not be able to cope with the peak load and will slow down the work of the whole enterprise.

The performance of the network depends on the coordination of Full-duplex and Half-duplex. In the Full-duplex mode, the transfer of data packets occurs simultaneously in two directions - from the switch to the computer and vice versa. In Half-duplex mode, the signal is transmitted only to one side. The built-in reconciliation function avoids conflicts during the operation of network devices using different modes.

Focus on

When choosing a switch, it is important to pay attention to the size of the switching table, which correlates the "names" of the ports with the MAC addresses of the computers. This parameter must be determined with the number of PCs on your network. In cases where there is not enough room left in the memory for the new network device to be written, it will delete the address of the rarely used PC, and after that it will start searching for it again. This significantly reduces performance.

Flow Control must have all gigabit switches, because it provides protection against data loss. With its help, two devices "agree" with each other, in what order and when to send a signal.

Switch Management

By the type of management switches are divided into two types - unmanaged and manageable. In the first case, we have a fully autonomous device without tools for manual adjustment and calibration. It is better suited for a small office network or for a home, because it has low cost, does not require human intervention. Its main drawback is low productivity, which does not allow it to be used in a large enterprise. The managed gigabit switch also functions in automatic mode, but it has a wide range of tools with which the administrator can easily adjust its operation. Typical representatives are JetStream, TP-Link, D-Link. A significant disadvantage is the high price.

10 Gigabit Switches

In a highly competitive environment it is important to be able to make decisions very quickly and give orders. To make this possible, it is necessary to equip the enterprise with high-speed switches providing data transmission at speeds up to 10 Gb / s. It is worth mentioning that such devices appeared on the market more than 10 years ago. However, they are still relevant, and they have not yet been replaced.

To connect a 10 Gigabit switch, you can use a fiber optic cable, a twinnaxial cable or a standard copper wire of the UTP / FTP standard. Today, the most popular devices are connected by a conventional copper wire. They provide data transfer using 10GBASE-T technology, have low cost and make the network as flexible as possible. Separately, it should be noted backward compatibility with gigabit networks.

Switch manufacturers

Our list is opened by Alcatel-Lucent. Its family of devices OmniSwitch is designed for building medium and large, as well as for the core device of small corporate networks. In the OmniSwitch 6850E, the 10 Gigabit switching function is available as an option, but the OmniSwitch 6900 already has 64 ports for high-speed packet transfer.

The company D-Link has in its assortment only two representatives of this category of devices. Its 8-port Gigabit desktop switch DXS-3600-16S provides PC connectivity through a fixed port SFP +, but in the DXS-3600-32S there are already 24 similar connectors. Both devices have a slot for the expansion module, through which it will be possible to connect to the network using 10GBASE-T technology.

Cisco can not please full-fledged equipment. However, it offers a more advantageous solution in the form of removable modules, for example, Nexus and Catalyst. Such "extensions" can be used to connect to the network both through a copper cable and through an optical fiber.

HP Corporation offers its gigabit switches for the needs of medium and small businesses. One of the brightest representatives is HP 6125G / XG, which is a hybrid device - a 1/10-gigabit switch. Only 10 Gigabit switches are represented by the models of the 5820 series. They support this speed at the SFP + landing sites. However, among devices, you can also find the PoE-Gigabit switch industrial series HP 5920.

What to choose for a home network?

If you use a wireless connection to connect devices to a home network is impossible or unacceptable due to the slow data transfer rate, it is better to use unmanaged switches. First, they are cheaper. Secondly, they are easy to connect and configure, do not require intervention from the user. The TP-LINK TL-SG1008D model promises to be the best option. The switch has 8 ports for connection, it works at the expense of the power supply unit, which is connected to the socket. Data transmission is guaranteed at speeds of 1 Gb / s.

If you want, you can choose for yourself an optical gigabit switch manufactured by TRENDnet or ASUS. The cost of such devices is at an acceptable level, and their functionality is sufficient to meet the needs of the home network.