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switches

Network switches route data packet traffic inside the network.
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Description

A switch is a device or component placed along a line that directs or redirects the path of electrons, bits or data packets.

Types of switches
Network switches
Network switches are devices that direct data packets coming in from multiple inputs to a destination on a local area network (LAN). The data packet comes into the switch, which forwards the packet. Using switches avoids the limitations of network hubs, which in a LAN are central point of connection for devices that have to share limited bandwidth through the hub. The switch can send data packets at the same time to different devices on the LAN. (The switch deals with traffic inside a network; a router connects networks together.)

The network switch is a hardware device that consists of input ports and output ports, where cables are connected. Encased in a housing, the switch usually has boards with integrated circuits for forwarding engine, replication engines, virtual output queues (VOQs) media access control (MAC), fabric connections and encryption. In the past, general purpose chips were used in switches, which created latency. Most of the network switch chips and infrastructure has moved to custom designs, mostly working at 28nm, but the chips in switches will be migrating to 7nm over the next year or two, which will significantly improve performance due to much greater density. Those are more generic chips, too, which means they will be less expensive than building a new chip from scratch (estimated to be somewhere in the neighborhood of $300 million at 7nm), and there will be an awful lot of them sold.

Right now, the industry is moving from 8.5 terabits to 26 terabits to keep up with SerDes.

The network switch has different configurations, architectures and throughput/speed capabilities. The requirements for switches depend on use case, such as:
• metropolitan area networks (MANs)
• data centers
• enterprise networks: a network switch here connects printers, computers, access points, servers, lights, among other devices.

Switches found in networks:
• LAN switch, such as LAN digital building switches
• Unmanaged switch: fewer connections, used in a home or conference room. Plug in and it works, without configuring the switch.
• Managed switch: more features and security for customizing the network. Good for managing traffic on a LAN and running bandwidth intensive applications.
• PoE switch: Power over Ethernet switch delivers power over existing Ethernet cables to devices.
• Stackable switch: switches that can be stacked and linked together.
Some network architectures are set up with multiple network switches that work together and take over for each if one fails. This configuration is called MLAG (Multi-Chassis Link Aggregation).

Optical switches
High-speed optical networks make it possible for people around the world to instantaneously communicate and share ideas. Tiny MEMS optical switches play a critical role in these enormous optical fiber systems. These switches combine mechanical, optical, and electrical domains.