A network switch is a hardware device that channels incoming data from
multiple input ports to a specific output port that will take it toward
its intended destination. It is a small device that transfers data
packets between multiple network devices such as computers, routers,
servers or other switches.
Network devices can be separated by the layer they operate on, defined by the OSI model. The OSI model conceptualizes networks separating protocols by layers. Control is typically passed from one layer to the next.
Some layers include:
Layer 1- or the physical layer or below, which can transfer data but cannot manage the traffic coming through it. An example would be Ethernet hubs or cables.
Layer 2- or the data link layer, which uses hardware addresses to receive and forward data. A network switch is an example of what type of device is on layer 2.
Layer 3- or the network layer, which performs similar functions to a router and also supports multiple kinds of physical networks on different ports. Examples include routers or layer 3 switches.
Other layers include layer 4 (the transport layer), layer 5 (the session layer), layer 6 (the presentation layer) and layer 7 (the application layer).
Whenever a host sends a frame to any other host, then the source host is stored with the port in the address table of the MAC address switch. A switch always stores the address of the source in the table. Unless a host does send some data, its MAC address and port number will not be stored in the table of the switch. Unless a host does send some data, its MAC address and port number will not be stored in the table of the switch. When you initialize the switch, the switch does not contain any information about any host and its address. In such a situation, when a host frame sends, its MAC address is stored in the table but due to no destination information, the switch sends the frame to all the hosts.
When you initialize the switch, the switch does not contain any information about any host and its address. In such a situation, when a host frame sends, its MAC address is stored in the table but due to no destination information, the switch sends the frame to all the hosts. As soon as the second host sends some data, its address also gets stored in the table. As soon as the second host sends some data, its address also gets stored in the table. Whenever a host sends the frames, the switch stores it if its address is not already present in the table. Thus a switch creates its table. When all the hosts’ addresses and port numbers come in the switch, the switch delivers the frame to all hosts only, delivering the same host to the host for which the data has been sent.
A network switch can be deployed in the following ways:
- Edge, or access switches: These switches manage traffic either coming into or exiting the network. Devices like computers and access points connect to edge switches.
- Aggregation, or distribution switches: These switches are placed within an optional middle layer. Edge switches connect into these and they can send traffic from switch to switch or send it up to core switches.
- Core switches: These network switches comprise the backbone of the network, connecting either aggregation or edge switches, connecting user or device edge networks to data center networks and, typically, connecting enterprise LANs to the routers that connect them to the internet.
Types of Switches
- Unmanaged switches
These are the switches that are mostly used in home networks and small businesses as they plug-in and instantly start doing their job and such switches do not need to be watched or configured. These require only small cable connections. It allows devices on a network to connect with each other such as a computer to a computer or a computer to a printer in one location. They are the least expensive switches among all categories.
- Managed switches
These type of switches have many features like the highest levels of security, precision control and full management of the network. These are used in organizations containing a large network and can be customized to enhance the functionality of a certain network. These are the most costly option but their salability makes them an ideal option for a network that is growing. They are achieved by setting a simple network management protocol(SNMP).
They are of two types:
- Smart switches:
These switches offer basic management features with the ability to create some levels of security but have a simpler management interface than the other managed switches. Thus they are often called partially managed switches. These are mostly used in fast and constant LANs which support gigabit data transfer and allocations.It can accept configuration of VLANs (Virtual LAN).
- Enterprise managed switches:
They have features like ability to fix, copy, transform and display different network configurations along with a web interface SNMP agent and command line interface. These are also known as fully managed switches and are more expensive than the smart switches as they have more features that can be enhanced. These are used in organisations that contain a large number of ports, switches and nodes.
- Smart switches:
- LAN switches:
These are also known as Ethernet switches or data switches and are used to reduce network congestion or bottleneck by distributing a package of data only to its intended recipient. These are used to connect points on a LAN.
- PoE switches:
PoE switches are used in PoE technology which stands for power over Ethernet that is a technology that integrates data and power on the same cable allowing power devices to receive data in parallel to power.Thus these switches provide greater flexibility by simplifying the cabling process.
Source: tech target, geeksforgeeks, include help, google.