Which one had more overhead a router or a bridge?

a. Routers are more expensive than bridges.

b. Routers operate at the first three-layers; bridges operates at the first two layers.

Routers are not designed to provide direct filtering the way the bridges do. A

router needs to search a routing table which is normally longer and more time

consuming than a filtering table.

c. A router needs to decapsulate and encapsulate the frame and change physical

addresses in the frame because the physical addresses in the arriving frame

define the previous node and the current router; they must be changed to the

physical addresses of the current router and the next hop. A bridge does not

change the physical addresses. Changing addresses, and other fields, in the

frame means much unnecessary overhead.