10 Replies Latest reply: May 21, 2014 6:47 PM by Chandan Singh Takuli RSS

    Switch Vs. Bridge

    Ashiq

      What is the major difference between a switch and a bridge ?

      I am aware that they both are Layer 2 devices and they are both hardware based devices, Can someone give me an example where actually a bridge is used.

       

      Thanks in advance

        • 1. Re: Switch Vs. Bridge
          Steven Williams

          A bridge looks at the destination of the frame before sending, if the destination address is not on the other side of the bridge it will not transmit the data across. This helps break up one large broadcast domain into 2 by using one bridge device.

           

          A switch has multiple ports in which each port is its own collision domain, a switch will determine the source and destination of the incoming data and switch it to the port it needs to go to. Switch ports can be broken into many separate broadcast domains using vlans. A switch is more efficient in today's large networks.

          • 2. Re: Switch Vs. Bridge
            Ashiq

            So how does the bridge learns the address of the devices ?

            Does it learn the same way as the switch does, by filling entries in the filter table ?

            • 3. Re: Switch Vs. Bridge
              jneiberger

              There is no difference except for the number of ports. A switch is nothing more than a multiport bridge.

              • 4. Re: Switch Vs. Bridge
                Elvin Arias

                The bride is very software-dependent, but the switch is not. The switch use more sophisticated methods like ASICs. The port density is higher on switches,

                 

                Elvin

                • 5. Re: Switch Vs. Bridge
                  Selvin

                  A bridge make its decision in software (done by the Main Processor) and a switch make is decision in hardware.

                   

                  When we say anything is  done in the hardware it means that it's not done by the Main Processor.

                   

                  A bridge has one instance of spanning tree.. switch as mulitple instance of Spanning Tree.

                   

                  Bridge Supports only one VLAN

                  Switch Supports multiple VLAN - one spanning tree per-Vlan.

                   

                  Bridge...Design to connect multiple network

                  Switch...Design to connect End devices

                  • 6. Re: Switch Vs. Bridge
                    alib_15

                    Hmm .. not sure about that bit "Bridge Supports only one VLAN" and "A bridge has one instance of spanning tree".

                     

                    Cisco WAPs are often referred to as bridges and they support many VLANs.

                    • 7. Re: Switch Vs. Bridge
                      Chandan Singh Takuli

                      Hi Ashiq

                       

                      2 Major difference:

                       

                      1 -> Every port of bridge is connected to a shared common memory And port sends data to each other through that memory only. so it will be a bottle neck.just like a hub & spoke topology. where hub is common memory & spokes are port. Where as in switches every port is connected to every other port on switch creating a mesh topology and every port is also connected to the ASIC.

                       

                      2-> Bridges are software based where as switches are hardware based. for example: bridge functionality works like Windows running over a pc where as switches like BIOS runs on a pc.

                       

                      HTH