or more precisely, it's the 52 bit-time rule. Where the maximum round-trip
time
in a segment can not exceed the time needed to transmit 52 bits. Ie, if it's
a 10M
network, it has to take less than 5.2 us, if it's 100Mb network, then it'll
be 0.52 us
Leon Chang
CCNP, CCDA
----- Original Message -----
From: "Priscilla Oppenheimer" <[EMAIL PROTECTED]>
To: "Bowen, Shawn" <[EMAIL PROTECTED]>; "Li Song" <[EMAIL PROTECTED]>;
<[EMAIL PROTECTED]>
Sent: Tuesday, December 26, 2000 1:47 PM
Subject: RE: is this statement true ??
> At 01:07 PM 12/25/00, Bowen, Shawn wrote:
> >According to IEEE NO, 100 Meters is the max cable distance for Half or
Full
> >100MB Ethernet over TP. In reality, Yes it will extend the range, The
> >reason why is that at full duplex you can not have collisions, and
> >collisions are the main reason for the distance limitation (Cross Talk
comes
> >into play as well). The reason behind this is that in the original IEEE
> >spec the distance limitation was set so that a single 64Byte packet (the
> >smallest) could be transmitted down the line and would collide with
another
> >packet before the 64Byte packet header had been completely transmitted,
when
>
> Minor correction: The distance limitation is defined so that if a station
> is transmitting a minimum-size frame (64 bytes) and a collision occurs at
> the other end of the network, the collision will reflect back to the
sender
> while the sender is still sending. If this didn't happen, the sender would
> have stopped monitoring for a collision with its transmission, and would
> not automatically retry. An upper layer would have to retransmit, which
> takes a lot longer.
>
> >this does not happen properly you see late collisions, these indicate a
> >collision past the preamble header of the packet and indicate a cable
length
> >that is to long.
>
> A late collision is one that happens past the preamble and past the first
> 64 bytes of the frame. A collision within the first 64 bytes is legal,
> normal, and not late.
>
> Priscilla
>
> >If you need to even go close to the 100 Meter mark you
> >should consider 100BaseFX or similar.
> >
> >Shawn
> >
> >-----Original Message-----
> >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Li
> >Song
> >Sent: Monday, December 25, 2000 4:33 AM
> >To: [EMAIL PROTECTED]
> >Subject: is this statement true ??
> >
> >"full-duplex can be used over longer distance than
> >half-duplex" ??
> >what 's your opinion ??
> >
> >
> >_________________________________
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> >
> >_________________________________
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>
>
> ________________________
>
> Priscilla Oppenheimer
> http://www.priscilla.com
>
> _________________________________
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>
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