At which OSI layer do bridges operate?

Bridges operate at the Data Link Layer of the OSI model. This layer is responsible for node-to-node data transfer and handles error correction from the physical layer. Bridges primarily function to connect and manage traffic between different segments of a local area network (LAN) by analyzing MAC (Media Access Control) addresses. They filter traffic to ensure that data packets are sent only to the correct segment, thereby reducing unnecessary collisions and improving network efficiency.

In contrast, the other layers perform different functions; the Network Layer manages packet routing, the Transport Layer oversees end-to-end communication and data integrity, and the Physical Layer involves the transmission of raw data bits over a physical medium. Thus, bridges specifically enhance the efficiency of data flow at the Data Link Layer.