Passive and Active Hubs

mgmguy1mgmguy1 Linux Essentials certified , Cisco CCENT certified PA Member Posts: 480 ■■■□□□□□□□
Am I right by thinking that Passive Hubs,Active hubs and Switching hubs all map to the Physical Layer. Even thou there are suttle differences between all 3 hubs they all still are maped to the physical layer.
"A lot of fellows nowadays have a B.A., M.D., or Ph.D. Unfortunately, they don't have a J.O.B."

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Comments

  • Danman32Danman32 Member Posts: 1,243
    A switching hub is a switch, so it is considered layer 2, as it bases its forwarding on the MAC address. It's a new name for a bridge, though a bridge is commonly thought of as having only 2 ports.

    A hub floods all ports with the data from the source port, ignoring MACs.

    A passive hub has no signal amplification, where an active hub regenerates the signal exiting a port. At least that was the definitions in Arcnet days. In those days coils, capacitors and resistors were in the passive hubs, and the active hubs had transistors and ICs.
  • bighornsheepbighornsheep Member Posts: 1,506
    Danman32 wrote:
    A switching hub is a switch, so it is considered layer 2, as it bases its forwarding on the MAC address. It's a new name for a bridge, though a bridge is commonly thought of as having only 2 ports.

    A hub floods all ports with the data from the source port, ignoring MACs.

    A passive hub has no signal amplification, where an active hub regenerates the signal exiting a port. At least that was the definitions in Arcnet days. In those days coils, capacitors and resistors were in the passive hubs, and the active hubs had transistors and ICs.

    My recent studies and certification in Network+ confirms your definition of active and passive hub.

    Danman=> A switching hub is not a hub because it handles MAC address, a layer 2 sublayer.

    Moreover,

    A bridge is a layer 2 device that handles MAC addresses, but it forwards frames with a software database, whereas a switching (or switching hub) forwards with hardware, ie. integrated circuits.
    Jack of all trades, master of none
  • Danman32Danman32 Member Posts: 1,243
    No, there used to be hardware bridges before they started calling them switches. Usually they were used to break up a bus topology into 2 collision domains. When multiport bridges came around, they started calling them switches because they used similar algorithms used in telephony switches.

    And I think the reason switching hubs were called as such is because it is the hub of a star topology, as well as to get those unfamiliar with switches to understand what that was used for. It most often could be a direct replacement for a hub but provide switching functions.

    There is yet another explanation for switching hubs when dealing with mult-speed. Many would have a 10Mb bus hub and a 100Mb bus hub, and switch between them.
  • nelnel Member Posts: 2,859 ■□□□□□□□□□
    judging danman's certs and experiance, i think we should just sit back and listen ;)
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  • Danman32Danman32 Member Posts: 1,243
    I appreciate the compliment. I am open to other suggestions or interpretations though. We can all learn and benefit from it.

    Even some humorous ones. Like a switching hub that can't decide what it wants to be. Or maybe it has a multiple personality disorder. icon_wink.gif
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