Draytek VigorSwitch P1280, Руководство пользователя, Страница: 116 / 120

VigorSwitch P1280 User’s Guide 110
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
In full-duplex operation mode, both transmitting and receiving frames are processed
simultaneously. This doubles the total bandwidth. Full duplex is much easier than half duplex
because it does not involve media contention, collision, retransmission schedule, 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 the same as that in the half-duplex operation.
Because no collision will happen in full-duplex operation, for sure, there is no mechanism to
tell all the involved devices. What will it be if 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 introduced in the full-duplex operation.