C. ETHERNET TECHNICAL TERMS APPFNDIX B-62694ENlOlj
Now, in the standard of “IEEE802.3”, a node checks to
transmit the data normally. This function is called the
“heartbeat” function.
The Data Server board is made according to the standard of
“IEEE802.3”, so that this heartbeat function is supported.
Therefore, if you connect a tranceiver without this heartbeat
function, it may make the real transmission rate less because
an error occurs at all times transmitting the data.
Then the tranceiver connecting with the Data Server board
must support this heartbeat function.
SEGMENT
Originally, the extent which is connected by one
medium(cable) physically is called as “segment”. But the
meaning of the segment is changing for the lOBASE-T.
It is common opinion that the meaning of the segment is “the
extent which is act the CSMA/CD function”.
CSMA FUNCTION (Carrier Sense Multiple Access)
To transmit, a station waits for a quite period on the
medium(cable) (That is, no other station is transmitting) and
the sends the intended message in bit-serial form.
CD FUNCTION (Collision Detect)
If after initiating a transmission, the message collides with
that of another station, then each transmitting station
intentionally sends a few additional bytes to ensure
propagation of the collision throughout the system. The
station remains silent for a random amount of time before
attempting to transmit again.
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