FC-2 Features
96122 • Revision: F Chapter 5 Fibre Channel Operations 65
Timers
Sun StorageTek libraries use the timer values in TABLE 5-16.
Arbitrated Loop Timeout
The Arbitrated Loop timeout value (AL_TIME) is two times the worst case round-
trip latency of a very large loop.
Receiver_Transmitter Timeout
The Receiver_Transmitter timeout value (R_T_TOV) is used by the receiver logic to
detect a loop failure.
Error_Detect Timeout
The Error Detect Timeout value (E_D_TOV) is the maximum time permitted for a
Sequence Initiator between the transmission of consecutive data frames within a
single sequence. This is also the minimum time that a Sequence Recipient waits for
the reception of the next frame within a single sequence before recognizing a
Sequence timeout.
E_D_TOV includes the time required to gain access to the loop in addition to the
actual frame transmission time.
TABLE 5-16 Timer Summary
Timer Value
Implemented By
Initiator Target StorageTek
AL_TIME 15 ms R R Y
R_T_TOV 100 ms R R Y
E_D_TOV Private = 2 s
Public = supplied + 2 s
R
R
A
2
R
Y
Y
R_A_TOV
SEQ_QUAL
Private = 0 s
Public = 10 s (See note 1)
R A
2
Y
R_A_TOV
ELS
Private = 2 s
Public = 10 s
RRY
RR_TOV 300 s R Y
REC_TOV > = E_D_TOV + 1 s
minimum
RRY
ULP_TOV >= Operation specific
timer + 4 x REC_TOV
RN
Notes:
1. The division of R_A_TOV usage differs from the FC-PH because of the unique characteristics of an
Arbitrated Loop environment.
2. SCSI target devices that support Class 2 are required to implement this timer.
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