Anonymous asked in Computers & InternetComputer Networking · 1 decade ago

What is Carrier Sense Mulitple Access(CSMA), and Carrier Sense Multiple Access with Collision Detection?

What is Wavelength Division Multiplexing Access (WDMA). I heard these are access protocols and where would these types of protocols would be used?

3 Answers

  • 1 decade ago
    Favorite Answer

    Carrier Sense Multiple Access/Collision Detect (CSMA/CD) is the protocol for carrier transmission access in Ethernet networks. On Ethernet, any device can try to send a frame at any time. Each device senses whether the line is idle and therefore available to be used. If it is, the device begins to transmit its first frame. If another device has tried to send at the same time, a collision is said to occur and the frames are discarded. Each device then waits a random amount of time and retries until successful in getting its transmission sent.

    CSMA/CD is specified in the IEEE 802.3 standard.

    In fibre optic telecommunications, wavelength-division multiplexing (WDM) is a technology which multiplexes multiple optical carrier signals on a single optical fibre by using different wavelengths (colours) of laser light to carry different signals. This allows for a multiplication in capacity, in addition to making it possible to perform bidirectional communications over one strand of fibre.

    The term wavelength-division multiplexing is commonly applied to an optical carrier (which is typically described by its wavelength), whereas frequency-division multiplexing typically applies to a radio carrier (which is more often described by frequency). However, since wavelength and frequency are inversely proportional, and since radio and light are both forms of electromagnetic radiation, the two terms are closely analogous.

  • 1 decade ago

    Carrier Sense Multiple Access with Collision Detection

    (CSMA/CD) is the LAN access method used in Ethernet. When a device wants to gain access to the network, it checks to see if the network is free. If the network is not free, the device waits a random amount of time before retrying. If the network is free and two devices access the line at exactly the same time, their signals collide. When the collision is detected, they both back off and wait a random amount of time before retrying.

    for WDMA... read white paper at

  • Anonymous
    1 decade ago

    ITS from Network communications fild.

    it means when u have computers connected in network .

    if they are in the same colision domain(mean only one can send information in time) can happen more then one to send data so signal will be damaged.ex. 1V from first + 1 V from second computer = 2V All computers can see that something is wrong "Carrier Sense Multiple Access with Collision Detection".

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