Bridge is termed as a network device which is helpful in filtering the data load of the traffic by dividing it into segments or packets. They sare used to lower the load of traffic on the LAN and other networks. Bridges are passive devices, because there is no interaction between bridged and the paths of bridging. Bridges operate on the second layer of the OSI model that is the data link layer.
How Bridges Works
When various network segments are established at the data link layer of the OSI model, we refer to it as bridge. However when the packets of data are transferred along a network , without locating the network addresses this process is termed as bridging. The process of bridging is helpful in locating the addresses of unknown addresses to which it is viable to send data. In bridging the data packets contain a header or a packet header which holds the address to the intended device. Bridge can remember and recall the address of the devices for further transmission. There are two kinds of bridging modes, the transparent bridging and the source routing bridging. When the process of bridging occurs, it makes a bridging table along side where it stores the MAC addresses of the various terminals. This table helps the bridges to send the data packet to the exact location next time. However when a specific address does not meet the contents of the bridging table, the data packet is forwarded further ahead to every attached terminal in LAN except from the computer it is connected to. This type of bridging is called transparent bridging. When the source computer presents pathway information within the packet, this type of bridging is known as source route bridging. It is most commonly used in used on Token Ring networks.
Major limitations of network bridges
A network bridge does not incur any communication between network path and the physical hosts of the data. The data packets are not guided as through which path to travel along. Therefore a network data packet is sent to every network terminal. Bridging does not acquire any address placement related to the physical address of the connected terminals. Thus a data packet is sent to every address. This is a bungling way of transporting data. Crippling overhead can occur in stumpy and slow links. In more sever cases broadcasting storm can occur.
Advantages and disadvantages of network bridges
There are many advantages and disadvantages of using network bridges. Bridges have simple configuration modes. Bridges are simple to use and they are relatively inexpensive. It can prove to be an alternative to switches and help resulting in micro segmentation. Bridges help to lower the data load over the data link layer. It appears to be translucent over the MAC layer. Bridges can be effectively programmed to disallow packets from meticulous networks. Bridges are more reliable if one wants to lower the bandwidth utilization. The disadvantages of bridges are that first of all bridges are unable to read specific IP address; they are more concerned with the MAC addresses. Bridges cannot help to build a communication network between the networks of different architectures. Bridges transfer all types of broadcast messages, thus bridges are unable to limit the scope of these messages. Extremely large networks cannot rely on bridges; therefore the large networks as WAN which are IP address specific can not make use of it. Bridges are expensive if we compare the prices of repeaters and hubs to it. Bridging is most suitable to be used for LAN network traffic data load. It is unable to handle more complex and variable data load such as occurring from WAN.