What Is Bridge?
A bridge is a device used to connect more than one local area Network (LAN) segments together. It operates at the data link layer and provides packet filtering by sending only those packets that are addressed to the other side of the network. A bridge is capable of connecting to networks with different hardware architecture, like Ethernet and token ring.
Types of Bridges
There are 3 Primary Bridging methods
· Transparent Basic Bridge: A transparent basic bridge is the simplest type of bridge and it stays “transparent” or invisible to the other devices on the network. This type of bridge can briefly store data before it can forward it to the next network, but only serves the basic purpose of blocking or forwarding data based on MAC address and no conversion of traffic is performed.
· Source Routing Bridge: This type of bridge deduces the route a packet should take through the network by searching for information embedded by the source of the traffic. It does so by looking for a special data field in the packet, the routing information field (RIF). if it fails to get that information, it transmits an “explorer” packet which collects information about the IDs of the bridges and the networks as it travels through the network and sequential map of the network is sent back to the transmitting device. An SRT bridge uses such information to determine the path of the data packets on the network.
· Source Routing Transparent Bridge: This type of bridge is a hybrid of transparent and source bridges. Such bridges are capable of transmitting data packets irrespective of whether or not the source routing information is available. The image illustrates the source routing and transparent bridges.