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.