A bridge in a computer network is a device that connects multiple subnetworks or LAN segments to form a single, larger network. It operates at the data link layer (Layer 2) of the OSI model and uses MAC addresses to filter and forward network traffic intelligently between these segments

Key Functions of a Network Bridge:

• Connects multiple LANs to create an extended LAN.
• Divides a large network into smaller segments to reduce traffic and collisions.
• Maintains a MAC address table to learn which devices are on which segments.
• Forwards packets only to the segment where the destination device resides, filtering unnecessary traffic.
• Helps reduce network congestion and improve performance by controlling broadcast domains

How It Works:

• The bridge listens to all incoming frames on connected segments.
• It learns the MAC addresses of devices on each segment and records them in its table.
• When a frame arrives, the bridge checks the destination MAC address.
• If the destination is on the same segment as the source, the frame is filtered (not forwarded).
• If the destination is on a different segment, the frame is forwarded to that segment.
• If the destination MAC is unknown, the frame is broadcast to all segments

Types of Bridges:

• Transparent Bridge (Learning Bridge): Automatically learns MAC addresses and builds its forwarding table.
• Source Routing Bridge: Uses routing information provided by the sending device to avoid loops

Difference from Routers:

• Bridges operate at Layer 2 and forward traffic based on MAC addresses within the same network.
• Routers operate at Layer 3 and route traffic between different networks based on IP addresses

In summary, a network bridge is a Layer 2 device used to connect and segment LANs, improving network efficiency by filtering traffic and reducing collisions while extending the physical size of the network