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CrossFire 8600/860 5 Token-Ring Switches v. 1. 2, P/N: 710001641 Switc h Theory of Operatio n
faulty packets is high, the store and fo rward mode is us ed. This provide s opt imiz ed
performance but introduces variable latency.

Token-Ring Port Operation Modes

Each Token-Ring port may operate in one of the following modes:
•Half-duplex concentrator port
The port behaves like an active MAU port for classical Token-Ring. Connects
to a single station in half-duplex mode. This is also known as Token Passing
(TKP) port mode.
•Half-duplex station emulation
The port is connected to a port on a MA U. Connec ts to a clas sic al Token-Ring
segment with multiple stations. This is also kno wn as Token Passing (TKP)
station mode.
•Full-duplex concentra tor port
Connects to a single station or to another switch in full-duplex mode. This is
also known as Transmit Immediate (TXI) port mode.
•Full-duplex station emulation
Connects to another Token-Ring switch. This is also known as Transmit
Immediate (TXI) station mode.
•RI/RO-like connection
The mode of operation can be configured manually or sensed automatically with
the exception of RI/RO, when equipment is connected to the port. T he media speed
(4 or 16 Mbps) can also be manually configured or automati call y sensed in all por t
modes.

RI/RO-Like Connection

On CrossFire 8600, a RI/RO-like connection is availabl e on fiber expansion ports
and on ports 19 and 20. On CrossFire 8605, a RI /RO-like conne ction is pos sible on
all the 20 fiber ports and on fiber expansion ports.
This feature allows the switch to connect to CAU/LAM systems using the RI/R O
connections thus providing a RI/RO-like functi onality. This enables the switch to
be easily instal le d in existing Tok e n-Ring network s.
A loop-back function has been implemented on these ports so that if the port is
disabled or the switch is powered off there will not be a break in the at tache d main
ring. This means that attaching a cable from the RI port of a MAU port to one of
the two switch ports in effect joins the primar y and the bac kup ring in a MAU/CAU
main ring system. Connecting the other end of the RI/RO connection to the other
switch port, creates redundant paths becau se t he two swi tch port s are c onn ected to