GarrettCom 4K16 Manual De Usuario

Magnum 4K16 Switches    Installation and User Guide       

(12/05) 

 

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connected to an another auto-negotiating device, there are 4 different speed and F/H 

modes selection depending on what the other device supports.  These are: (1) 100Mb 

full-duplex, (2) 100Mb half-duplex, (3) 10 Mb full-duplex and (4) 10 Mb half-duplex. 

The auto-negotiation logic will attempt to operate in descending order and will normally 

arrive at the highest order mode that both devices can support at that time. (Since auto-

negotiation is potentially an externally-controlled process, the original “highest order 

mode” result can change at any time depending on network changes that may occur).  If 

the device at the other end is not an auto-negotiating device, the 4K16-Switch’s RJ-45 

ports will try to detect its idle signal to determine 10 or 100 speed, and will default to 

half-duplex  at that speed per the IEEE standard. 

 

      General information - 

 the devices at both ends of the cable are capable of operation at either 10 

Mb or 100Mb speed and/or in full- or half-duplex mode, and can 

send/receive auto-negotiation pulses, and . . .  

 --   when the second of the two connected devices is powered up*, i.e., 

when LINK is established for a port, or 

--   when LINK is re-established on a port after being lost temporarily. 

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NOTE  –  some NIC cards only auto-negotiate when the computer system 

LINK – enabled” rule above, but may be occasionally encountered. 

When operating in 100Mb half-duplex mode, cable distances and hop-counts 

may be limited within that collision domain. The Path Delay Value (PDV) bit-times must 

account for all devices and cable lengths within that domain. For Magnum 4K-Series 

Fast Ethernet switched ports operating at 100Mb half-duplex, the bit time delay is 50BT. 

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

enabling simultaneous bi-directional collision-free data movements on a port.  The 

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

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