As a side note, Full Dup and CSMA/CD are impossible to have together, since Full dup uses separate paths (wires) there can be no collisions.
=======================
Clayton Dukes
Sr. Network Engineer
Landstar System, Inc.
Jacksonville, FL
904-390-1109
http:/www.landstar.com
=======================
-=]-----Original Message-----
-=]From: Vern Stitt [mailto:[EMAIL PROTECTED]]
-=]Sent: Wednesday, May 10, 2000 10:33 AM
-=]To: [EMAIL PROTECTED]
-=]Subject: Re: CSMA/CD : full duplex
-=]
-=]
-=]Full duplex does not require CSMA/CD. Full duplex requires a switch.
-=]Transmit and receive are done on separate wires to a switch.
-=] The switch
-=]then performs all arbitration internally. This
-=]theoretically makes 200Mbps
-=]possible, if the transmit and receive pipes are both kept
-=]full at 100Mbps.
-=]
-=]Half duplex was originally done on a single wire (10base5
-=]and 10base2) so
-=]the receive wire and the transmit wire were the same wire.
-=]10baseT only
-=]changed the physical media but it still "acts" like a single
-=]wire if it is
-=]attached to a hub rather than a switch. In this case,
-=]CSMA/CD (Carrier
-=]Sense Multiple Access with Collision Detect) must be used by
-=]all users of
-=]the 10baseT hub, 10base2 or 10base5.
-=]
-=]Vern Stitt, AE, ASE, CCNA, MCSE
-=]
-=]Dan West <[EMAIL PROTECTED]> wrote in message
-=][EMAIL PROTECTED]" TARGET="_blank">news:[EMAIL PROTECTED]...
-=]> Sorry to ask such a simple question--but the CCNA book
-=]> is still unclear as to what's going on.
-=]>
-=]> Half-duplex ethernet uses CSMA/CD for arbitration on
-=]> the link. Does full duplex use it as well for
-=]> arbitration? The book makes it sound like if you are
-=]> running full-duplex that the CSMA/CD is not necessary.
-=]> It mentions half-duplex looping a duplicate frame onto
-=]> the recieve wire from the transmit wire.
-=]>
-=]> Thanks.
-=]>
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