Bridge

A bridge goes one step up on a hub in that it looks at the destination of the packet before sending. If the destination address is not on the other side of the bridge it will not transmit the data.

• A bridge only has one incoming and one outgoing port.

• To build on the email analogy above, the bridge is allowed to decide if the message should continue on. It reads the address bob@smith.com and decides if there is a bob@smith.com on the other side. If there isn’t, the message will not be transmitted.

• Bridges are typically used to separate parts of a network that do not need to communicate regularly, but still need to be connected.

Bridges are used to extend networks by maintaining signals and traffic.

OSI: Bridges are on the data link layer so in principle they are capable to do what switches do like data filtering and separating the collision domain, but they are less advanced. They are known to be used to extend distance capabilities of networks.

In a comparison with switches, they are slower because they use software to perform switching. They do not control broadcast domains and usually come with less number of ports.