Collision Broadcast Domains

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All stations on an Ethernet segment are connected to the same segment. Therefore, all signals are received by all the devices. When devices sent signals at the same time, a collision occurs. A scheme is need to detect and compensate for collisions.

  • Collision domain  -  A group of devices connected to the same physical medium so that if two devices access the medium at the same time, a collision results. This is a Layer 1 domain.

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  • Broadcast domain -  A group of devices on the network that receive on another’s broadcast messages. This is a layer 2 domain.

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  • Ethernet Hubs -  Device that allow the concentration of many devices into a single segment. They have the following characteristics.
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    1. Physical layer devices.
    2. Do no manipulate or view traffic.
    3. Do not create separate collision domains.
    4. Use carrier sense multiple access collision detect (CSMA/CD).
    5. When a collision occurs, both stations resent the signal after a random period.
    6. Collisions increase with the number of the stations.
    7. Regenerate the signal, allowing traffic to travel longer distances.