NS3000/iX Operations and Maintenance Reference Manual (36922-90039)

176 AppendixA
LINKCONTROL Command
NS 3000/iX LAP-B Link Statistics
LAPB Parm K. The LAPB Parm K field displays the configured
number of unacknowledged frames that are allowed in the network at
any given time. For example, if this value is set to seven (7) for a node,
and that node transmits seven (7) packet frames onto the network, it
cannot transmit another frame until one or more of the transmitted
frames are acknowledged.
Connect Timeout. The Connect Timeout field displays the current
logical link level 2 connection timeout. The Connect Timeout parameter
sets the amount of time a node will wait for a logical connection to a
remote node to be established. If this timer expires, the node aborts the
connection attempt. The abort process can take several additional
seconds.
LAPB Parm T1. The LAPB Parm T1 field displays the current value of
the T1 timer. The T1 timer waits the specified number of
hundredths-of-seconds for a particular frame to be acknowledged. A
frame that is transmitted, but not acknowledged, before the T1 timer
expires, is retransmitted.
Local Timeout. The Local Timeout field displays the value specified
for the Local timer. This timer, also called a heartbeat timer, is used to
monitor whether the system and/or the PSI card are functioning. The
PSI card, and the system, transmit a signal, called a heartbeat signal,
to each other on a specified schedule. If, for example, the heartbeat does
not arrive at the PSI card from the system (or vice-versa), the card or
system waits the number of seconds specified by this field. If no
heartbeat arrives before this timer expires, the link is dropped. You can
determine whether the PSI card or the system failed by checking to see
which device is still active. The default for this field is 60 seconds and it
is recommended that you do not change the value of this field. The PSI
always waits 20 seconds longer than the system waits before it drops
the link.
LAPB Parm N2. The LAPB Parm N2 field displays the maximum
number of times a frame is retransmitted after the LAPB Parm T1
expires. The frame is retransmitted at the LAPB Parm T1 interval for
the number of times specified in this field. When this count is depleted,
the frame is retransmitted at 20 second intervals. If no response is
received after these transmissions, the link is brought down.
A node that is configured with the value specified in Figure A-2 will
attempt to retransmit an unacknowledged frame a maximum of
20 times at T1 intervals.
Transmission Speed. The Transmission Speed field displays the
current transfer rate, or clocking, configured for the node in the
NMMGR Link screen. If modems are used, the modems will control the
clocking. The PSI card transmits at the clocking setting of the modem
and ignores the value configured in this field.