Networking Basics: A Comprehensive Guide

Switches

Network switches are similar to network hubs, but they are more intelligent. A network switch examines incoming packets, determines the source and destination addresses, and routes the packet accordingly. By forwarding packets only to the intended recipient, switches significantly conserve bandwidth.

Modern network switches commonly offer speeds of 10/100/1000 Mbit/sec, as well as 10/100 Gbit/s ports. Switches operate at Layer 2 of the OSI model and are often recognized as multiport bridges.

Packet Forwarding Methods in Layer 2 Switches

Layer 2 switches use several methods to forward packets:

1. Store and Forward: This method buffers the entire frame and performs a checksum before forwarding it.

2. Cut-Through: This method doesn’t perform error checking. The switch reads the frame’s hardware address and immediately forwards the packet.

3. Fragment-Free: This is a hybrid approach combining Store and Forward and Cut-Through. The switch checks the first 64 bytes of the frame, which contain addressing information, to determine the destination. Error checking is typically handled by Layer 3 and 4 devices, usually the router or the end device.

4. Adaptive Switching: This method automates the switching between the other three modes based on network conditions.