What you mean by bridge ?
A bridge is a hardware device that is used to connect two or more local area network for exchange of data. They can connect that LANS having different cabling or protocol and operate the data link layer of OSI model . for managing flow of data between two LANS it depends on the address of every packet of data receiving . by it .
Bridge are used to connect two subnetworks which use identical protocol .
It basically connect two LANS to from an extand LAN.
A bridge basic function
Examining and learning the address of the nodes .
Frams filtering reformatting and forwarding.
Routing the frames.
Bridge connecting two LANS . main function of such bridge
Marketing LAN Accounting LAN
1. It reads all frames transmitted on first LAN and accpect those addressed to any station on second LAN.
2. It uses the medium access control protocol for second LAN and retransmit each frames onthat.
3. It similarly reads frames from second LAN accpect them and retransmits them to first LAN.
A bridge makes no modification to formate or content of the frames .rather it simply copies it from LAN 1 and retransmits it on LAN2 .
A bridge should have enough buffer space to meet peak demands as many frames at a faster rate may arrive over a short period of time to it .it also contain addressing and routing intelligence.