Network Bridge and Router serve different purposes in a network environment. Here are the key differences between the two:
1. Function: A network bridge operates at Layer 2 of the OSI model and connects two separate networks, allowing them to communicate as one. It simply extends the network by forwarding data between two physical or virtual network segments without modification. On the other hand, a router operates at Layer 3 and connects different networks (LANs, WANs, or the Internet) by choosing the best path for data packets to reach their destination.
2. Addressing: A bridge works with MAC addresses, which are unique identifiers assigned to network interfaces, to forward traffic between connected networks. It doesn't modify the source or destination addresses of the data packets. In contrast, a router uses IP addresses to direct traffic. It examines the IP header of a packet and determines the optimal path to forward the packet based on the destination IP address.
3. Decision Making: Bridges make forwarding decisions based on the destination MAC address present in the frame's header. They maintain a MAC address table to keep track of which devices are connected to each network segment. Routers, on the other hand, utilize routing tables, which store information about networks and their associated IP addresses, to make intelligent decisions regarding the path of data packets.
4. Network Segmentation: Bridges are commonly used to segment large networks into smaller parts to improve performance and security, such as dividing a LAN into multiple smaller LANs. Routers, on the other hand, connect different networks and enable communication between them.
5. Broadcast Domain: Bridges extend the broadcast domain, meaning that broadcasts sent on one side of the bridge will be received by devices on the other side. Routers, however, do not propagate broadcast messages. They use techniques like network address translation (NAT) to allow multiple devices on a network to share a single public IP address.
6. Network Layer Functions: Routers provide additional functionalities at the network layer, such as network address translation (NAT), port forwarding, firewall capabilities, and traffic shaping. These features give routers more control over network traffic and enhance network security.
In summary, network bridges primarily extend networks and connect two separate networks as one, while routers connect different networks and make intelligent decisions about routing data packets between them. Routers offer more advanced functionalities at the network layer and are commonly used for connecting networks and providing access to the Internet.