---

---

Hub is a physical layer device and have no built-in intelligence in it. Hub simply repeats signal given to them on all other ports and also perform regeneration of data signals. Hubs need no configuration and no processing is done at the hub to slow down the network performance. Hib is basically a multi-port repeater.The other function of Hub is to extend the network but that factor also depend on the type of cable i.e. co-axial or twisted pair cable. Brcause of no intelligence built in it it cannot perform any filtering of data that on which port data need to be send or not. Hub simply used on shared LAN's.
Bridge on the other hand is a layer 2 device with some intelligence built in it and it works on the method of MAC addresses (hardware address of the device burned into the ROM of LAN Card, a physical identification of the device on the LAN). It connects similar LAN's together that use identical protocols for the physical and data link layer, because the devices use same protocols the amount of processing is minimal and bridges are also capable of connecting dissimilar LAN's together like Token Ring and Ethernet.Bridge is basically a two port device.
Switch is also a layer 2 device and work on the same principle as bridge does but there is a difference that switch is a multiport bridge that ranges from 8-ports to 16-ports and so on, here layer 2 switching is hardware based and handled by a specialized hardware called application specific integrated circuits (ASIC). This chip allows a silicon chip to be programmed to perform a specific task and the function si perfromed at much higher speeds and it provide low latency due to higher speed. Both bridge and switch uses a MAC table for traffic flow and uses these addresses to filter and forward traffic. Basic deifference between switch and Bridge is that switch have superior throughput performance, high port densities. As bridge connect two LAN's both LAN's have multiple PC's in them so there is huge chances of frame collision on a wire sent by two PC's at the same time that disturb the network lower the network performance and also congestion that clog the network too so there is a single collision domain on one LAN that is connected to one port of the bridge whereas switch has a single port attach to only one computer(PC) and there is absolutely no chance of collision as the PC has a dedicated bandwidth so each port on switch is in a separate collison domain and this eliminates the posibility of collisions and contention issues in the network this concept is somewhat different from bridge device in which there is both contention and collision problem in LAN.
Router is specialized device work at layer 3 of the tcp/ip and osi model and connects different LAN's together. It uses IP addresses to differentiate between the networks and perform routing to select the best through the network towards the intended destinatin using the routing table built with the help of routing protocol.Security parameters and Quality of Service (QoS) parameters both implement on routers for specified type of network traffic. It provide connectivity between VLAN's in a switched environment.It divides the network into multiple collision and broadcast domains.An administrator can allow or deny specific IP addresses based traffic using router and it work on lower three layers and switch & bridge on lower two layers and hub on physical layer.Router has an IOS built in it for configurations and connect multiple remote locations of a network.

---

Posted by sizzlingfauji

Please visit:

www.experts-exchange.com/Networking/Q_21139422.html

---

Posted by sagitraz

www.edaboard.com/search,switch-lan.html

---

Posted by crouse

www.nutt.net/2004/difference-in-hub-switch-bridge-router

---

Posted by crouse