Bridge : Computer Network

  " Bridge is May be a combination of hardware and software or individual is used to connect two segment of same LAN (Same IP Domain). Bridge decreases the network traffic and also used to connect two different platform LANs like UNIX and Windows. " 

    A network bridge is software or hardware that connects two or more networks so that they can communicate.

    People with home or small office networks generally use a bridge when they have different types of networks but they want to exchange information or share files among all of the computers on those networks.

     Here's an example. Let's say you have two networks: in one, the computers are connected with cables; and in the other, the computers are connected using wireless technology. The wired computers can only communicate with other wired computers, and the wireless computers can only communicate with other wireless computers. With a network bridge, all of the computers can communicate with each other.

Difference between switch and bridge

     Network Switches and Bridges are both Layer 2 devices. They operate at the Data Link Layer (Layer 2) of the OSI Reference Model. Network Switches and Bridges have many similarities and similar function. But Switches are considered as superior devices than bridges.

Bridge

    A bridge is a product that connects a local area network (LAN) to another local area network that uses the same protocol (for example, Ethernet or token ring). You can envision a bridge as being a device that decides whether a message from you to someone else is going to the local area network in your building or to someone on the local area network in the building across the street. A bridge examines each message on a LAN, "passing" those known to be within the same LAN, and forwarding those known to be on the other interconnected LAN (or LANs).In bridging networks, computer or node addresses have no specific relationship to location. For this reason, messages are sent out to every address on the network and accepted only by the intended destination node. Bridges learn which addresses are on which network and develop a learning table so that subsequent messages can be forwarded to the right network.

Switch

     A Switch of data to its next destination. A switch may also include the function of the router, a device or program that can determine the route and specifically what adjacent network point the data should be sent to. In general, a switch is a simpler and faster mechanism than a router, which requires knowledge about the network and how to determine the route.

    Relative to the layered Open Systems Interconnection (OSI) communication model, a switch is usually associated with layer 2, the Data-Link layer . However, some newer switches also perform the routing functions of layer 3, the Network layer. Layer 3 switches are also sometimes called IP switches.