Lucent Technologies 6000 User Manual

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6-4
MAX 6000/3000 Network Configuration Guide
Configuring X.25
Configuring the logical link to an X.25 network
The next set of parameters in Ethernet > X.25 > X.25 profile includes defining the maximum 
number of seconds before recovery procedures begin, how many times the MAX can resend 
frames when the timer expires, and the maximum number of sequentially numbered frames 
that can be unacknowledged:  
X.25 profile parameters
The next set of parameters in Ethernet > X.25 > X.25 profile includes defining features on a 
X.25 connection, such as the minimum and maximum X.25 packet size to the duration of 
timers to receive or send X.25 packets:
Parameter
Specifies
LAPB T1
Maximum number of seconds the transmitter waits for 
acknowledgment before initiating a recovery procedure (Response 
timeout). The default is 3 seconds.
LAPB N2
How many times the MAX can resend a frame when the LAPB T1 
timer expires. The default is 20. This relatively high value increases the 
probability of a correct transfer of data.
LAPB k
Maximum number of sequentially numbered frames that can be 
unacknowledged at a given time. This value is also called the Level 2 
Window Size or the Frame Window Size. The default is 7. Higher 
values enable faster throughput. 
Parameter
Specifies
X.25 Seq Number 
Mode
The number of frames a sender can transmit before requiring an 
acknowledgment of the first frame. The protocol increments a 
sequence number in the frame header, and places the value into the 
next outgoing frame. The sequence number identifies each frame that 
has not yet been acknowledged.
X.25 Link Setup 
Mode 
Whether or not the X.25 link comes up in active- or passive- 
disconnect mode. In active-disconnect mode (the default), the link 
layer sends a DISC, and the packet layer sends a Restart-Request 
packet, upon initialization. In passive-disconnect mode, the link layer 
sends SABM(E) upon initialization and issues a restart to the network 
only upon receipt of a Restart-Request packet. It does not issue a 
Restart-Request packet upon initialization, but responds to Restart 
packets it receives.
X.25 Node Type
Whether or not the MAX interacts with the remote end of the 
connection as a DTE (the default) or a DCE (when emulating the X.25 
network). Data Terminal Equipment (DTE) is a device that an operator 
uses, such as a computer or a terminal. Data Circuit-Terminating 
Equipment (DCE) is a device that connects the DTE to a 
communications channel.
X.25 window size
The default for maximum number of outstanding data packets that can 
accumulate before the MAX requires an acknowledgment. The default 
is 2.