30
Parameter
value/LAN 10Base 100Base 1000Base
Max. collision
domain DTE to
DTE
100 meters 100 meters for UTP
412 meters for fiber
100 meters for UTP
316 meters for fiber
Max. collision
domain with
repeater
2500 meters 205 meters 200 meters
Slot time 512 bit times 512 bit times 512 bit times
Interframe Gap 9.6us 0.96us 0.096us
AttemptLimit 16 16 16
BackoffLimit 10 10 10
JamSize 32 bits 32 bits 32 bits
MaxFrameSize 1518 1518 1518
MinFrameSize 64 64 64
BurstLimit Not applicable Not applicable 65536 bits
Table 3-4 Ethernet parameters for half duplex mode
In full-duplex operation mode, both transmitting and receiving frames are
processed simultaneously. This doubles total effective bandwidth. Full duplex is
much easier than half duplex because it does not involve media contention, collision,
retransmission schedule and padding bits for short frame. The rest functions follow
the specification of IEEE802.3. For example, it must meet the requirement of
minimum inter-frame gap between successive frames and frame format remains the
same as that in the half-duplex operation.
Because no collision will occur in full-duplex operation, there is no
mechanism to tell all the involved devices. What will it be if the receiving device is
busy and a frame is coming at the same time? Can it use “backpressure” to tell the
source device? A function flow control is this introduced in the full-duplex operation.