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Basic Rate Interface (BRI)Feature
Description: Timers and Counters
This option sets the timer and counter thresholds. The factory settings for
thresholds are standard and rarely need to be changed. (See "At
a Glance" in this section for factory settings and valid ranges.) When
no response is received from the network before the duration of the timer setting,
the system takes the appropriate corrective action.
The programmable timers and counters are as follows:
- T200 Timer - Times the minimum time that the link layer waits
for an acknowledgment of link establishment, information, or polling supervisory
frames sent from the system to the network before resending
the frames.
- T203 Timer - Maximum time that the link layer can remain inactive.
- T303 Timer - Times the delay in network response when the system sends a setup message to initiate an outgoing call.
- T305 Timer - Times the delay in network response when the system sends a disconnect message to clear a call.
- T308 Timer - Times the delay in network response when the system sends a release message to clear a call.
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CAUTION! |
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After initial installation, these timers rarely, if ever, should be
changed. |
Other timers and counters used by the system are not programmable:
- N200 Counter - Counts the number of times the system can transmit
a message on a D-channel because no link layer acknowledgment is received
from the network. The value for this counter is 3.
- N201 Counter - Counts the maximum number of Layer 3 bytes the system
can send or receive in a single D-channel message. The value for this counter
is 260.
- N202 Counter - Counts the maximum number of times that Layer 2 should
retransmit TEI-REQUEST frames before notifying Layer 3. The value of this
counter is 3.
- K Counter - Counts the number of Layer 3 unacknowledged messages
sent from the system to the network on a D-channel. The value for this counter
is 1.
- T202 Timer - Minimum time Layer 2 must wait for an acknowledgment
of a TEI-REQUEST frame before initiating retransmission. The value of this
timer is 2 seconds.
- T309 Timer - Times the duration of a D-channel data link failure
(a loss of signaling for the entire BRI connection). The value of this timer
is 90 seconds.
- T310 Timer - Times the network delay following the receipt of a
call-preceding message on an outgoing call. The value of this timer is 60
seconds.
- T313 Timer - Times the delay in network response when the system
sends a connect message that indicates the completion of an incoming call.
The value of this timer is 4 seconds.
