Thursday, 1 November 2018

Layer 2 Switching



Switching  uses the hardware address of devices on a LAN to segment the network. Switching break up large collision domains into smaller domain and that a collision domain is a network segment with two or more devices sharing the same bandwidth. each port on a switch is actually its own collision domain. Layer 2 switching increase the bandwidth because each port of the switch, is its own self collision domain.  

Switch services  bridges used software to create and manage a Content Addressable Memory (CAM) table. new switches uses Application-Specific Integrated Circuits (ASICs) to build and maintain their MAC filter table. 

Advantage of using Layer 2 switchings:
  • Hardware-based bridging 
  • Wire speed
  • Low latency
  • Low cost 
Layer 2 switching increase the bandwidth because each port of the switch, is its own self collision domain.

 Layer 2 Switch Functions:


Address learning layer 2 switches remember the source hardware address of each frame received on an on interface and enter this information into a MAC database called a forward/filter table.

Forward/filter decisions when a frame is received on an interface, the switch looks at the destination hardware address, than choose the appropriate exit interface for it in the MAC database. This way, the frame is only forward out of the correct destination port.

Loop avoidance if the multiple connections between switches are created for redundancy purposes, network loops can occur, spanning tree protocol (STP) is used to prevent network.



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