GarrettCom Quad 사용자 설명서

Magnum Quad-Series Fiber Switches 

Installation and User Guide (06/03) 

enabling sim

ovements on a port.  The 

network t

, the 

cabl

ist

The

re

-

a port’s a

 

 Magnum Q- Series Switches incorporate a flow-control mechanism for Full-

ng 

 of a

his is 

most likely

he 

ltiple 

y 

ement the 802.3x flow control (non-

blocking) on F

3x flow control standard in order to communicate properly during 

normal operation. 

quad-switch implements a 

back-pre

tion 

Full-duplex Ethernet provides separate Transmit and Receive data paths, 

ultaneous bi-directional collision-free data m

opology must be a “star” type, not a “bus” type.  With full-duplex mode

e d

ance is only limited by the physical layer line driver and cable attenuation. 

re a  no collision-domain restrictions or limitations.  

The Magnum Quad-Series Switches perform half- or full-duplex mode auto

negotiation independently on all switched ports. If the device or node on the other end of 

ttached cable supports F/H mode auto-negotiation or is set to operate as full-

duplex, the Magnum Quad-Port Switch will negotiate to run full-duplex.  If the attached 

device or node doesn’t support F/H mode auto-negotiation (for example, if it is a 10 Mb

repeater or a standard 10 Mb hub), the Quad-Switch’s RJ-45 ports will default to operate 

at half-duplex. 

Duplex mode. The purpose of flow-control is to reduce the risk of data loss if a lo

burst

ctivity causes the switch to save frames until its buffer memory is full. T

 to occur when data is moving from a 100Mb port to a 10 Mb port, and t

speed difference makes the 10Mb port unable to keep up. It can also occur when mu

100Mb ports are attempting to transmit to one 100Mb port, and in other protracted heav

traffic situations.  

Magnum Q-Series Fiber Switches impl

ull-Duplex ports, which provides for a “PAUSE” packet to be transmitted 

to the sender when the packet buffer is nearly filled and there is danger of lost packets. 

The transmitting device is commanded to stop transmitting into the Quad-switch port for 

sufficient time to let the Switch reduce the buffer space used. When the available free-

buffer queue increases, the Switch will send a “RESUME" packet to indicate the 

transmitter to start sending the packets. Of course, the transmitting device must also 

support the 802.

Note: When in Half-Duplex mode, the 

ssure algorithm on 10/100 Mb ports for flow control. That is, the 

switch prevents frames from entering the device by forcing a collision indica
on the half-duplex ports that are receiving. This temporary “collision” delay 
allows the available buffer space to improve, as the switch catches up with the 
traffic flow. 

 

33 

.

.