Network switch
A network switch (switch) is a network device that connects computers, servers and other nodes into a local network and transmits data between them, sending frames only to the recipient. It operates at the data link layer of the OSI model and provides fast, reliable and secure connections within a network.
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A network switch (switch) is a network device that connects computers, servers and other nodes into a local network and transmits data between them, sending frames only to the recipient. Unlike a router, which connects different networks and directs traffic between them, a switch operates within a single network, increasing its performance and reducing the load on the line.
What is a network switch
A network switch (switch) is a device with several ports to which network devices are connected: computers, servers, printers, access points and other switches. When transmitting data, the switch remembers which port each device is on (a MAC address table) and sends a frame only to the intended recipient. This advantageously distinguishes a switch from a hub, which broadcasts data to all devices at once and heavily overloads the network. Modern switches operate at speeds of 1/10/25/40/100 Gbps and support management, VLANs, QoS, port aggregation and security functions.
Types of switches
Several types are distinguished by level and purpose. Unmanaged switches are simple and cheap, configure automatically, and are suitable for home and small office, but give no control over traffic. Managed switches support configuration of VLANs, traffic priorities, mirroring and monitoring; they are used in corporate networks. Access layer switches connect user devices at the edge of the network. Aggregation switches combine access switches and connect to the core. Core switches are high-performance devices at the heart of a data center network with redundancy. PoE switches power surveillance cameras, phones and access points over copper cable.
How to choose a switch
When choosing, the number of ports is assessed (leaving 20–30% for growth), the required speed (1 Gbps for workstations, 10–40 Gbps for servers and the core), the need for management and PoE support for powering devices. For medium businesses, managed switches with VLANs and security functions are recommended; data centers use switches with redundant power supplies and support for high-speed modules.
Switch and network security
Managed switches support security functions: port and VLAN isolation, port access control (802.1X), MAC address filtering and protection against frame forwarding to foreign segments. QoS configuration gives priority to services (telephony, video conferencing, DBMS). For critical infrastructure, redundant power supplies, link redundancy (spanning-tree, aggregation) and port monitoring are used. Regular firmware updates close vulnerabilities and extend the service life of equipment.
Frequently asked questions
What is a network switch and why is it needed?
A network switch is a device that connects computers, servers and other network nodes into one local network and transmits data strictly between the required devices. It is used to connect computers in an office, power cameras and access points, organize VLANs and build a network core in a data center.
How does a switch differ from a router?
A switch operates within one local network and transmits frames between its nodes based on MAC addresses. A router connects different networks and directs packets between them by IP addresses, and also provides internet access, NAT and inter-network protection.
What types of switches exist?
Unmanaged — simple, without configuration; managed — with VLAN, QoS and monitoring; access, aggregation and core switches — by the level of the network hierarchy; PoE switches — power devices over a network cable; industrial — for harsh operating conditions.
How many ports does a switch need?
Count the number of devices to be connected and add 20–30% of headroom for growth. For a small office, 8–24 ports are usually enough, for a medium company — 48-port models with several 10 Gbps uplink ports to the server room and higher-level equipment.
What is VLAN in a switch?
VLAN (virtual local area network) is a function of a managed switch that allows one physical network to be logically divided into several isolated segments: for example, separate VLANs for employees, guests, servers and IP telephony. This increases security and simplifies traffic management.
What is PoE and why is it needed?
PoE (Power over Ethernet) is a technology for supplying power to a device over the same network cable that carries data. PoE switches power surveillance cameras, WiFi access points and IP phones, which simplifies installation and does not require separate outlets at each device.
How is a managed switch better than an unmanaged one?
A managed switch allows configuring VLANs, QoS priorities, port aggregation, mirroring and traffic monitoring. This is necessary for corporate networks that require segmentation, performance control and information security.
Which switch should I choose for a data center?
For the data center core, high-performance 10/25/40/100 Gbps switches with redundant power supplies and fans, support for expansion modules and management via CLI/NETCONF are chosen. For server racks, models with port aggregation for connection to the core and storage systems are used.
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Network switch
A network switch (switch) is a network device that connects computers, servers and other nodes into a local network and transmits data between them, sending frames only to the recipient. It operates at the data link layer of the OSI model and provides fast, reliable and secure connections within a network.
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