main difference between bridge and hub
HUBS/CONCENTRATORS
Hubs, also known as concentrators or multiport repeaters, are used in star/hierarchical networks to connect multiple stations/cable segments. There are two main types of hubs: passive and active. An active hub takes the incoming frames, amplifies the signal, and forwards it to all other ports, a passive hub simply splits the signal and forwards it. Another type of hubs can be managed allowing individual port configuration and traffic monitoring, these are know as intelligent- or managed hubs.
Hubs operate on the physical layer of the OSI model and they are protocol transparent, that means they are not aware of the upper-layer protocols and such as IP, IPX nor MAC addressing
SWITCHES
To improve network performance even more switches were developed, switches are very similar to bridges; they also keep a table with MAC addresses per port to make switching decisions, operate in the OSI model and are protocol transparent.
Some of the main differences are:
- a switch has more ports than a bridge
- bridges switch in software whereas switches switch in hardware (integrated circuits)
- switches offer more variance in speed, an individual port can be assigned 10 Mb/s or 100 Mb/s or even more.
Added after 5 minutes:
i think no comparison between hub an switches coz hub layer first device an swtich layer two device similar to briges we use switches coz having asic processing its integrated circuits where in bridges software processing its slow an bridges haaving maximum 15 port where switches upto 500 ports
i think its clear now