Configuration

Configuring the X.25 Link

Step

2. Enter or modify field values as required (refer to the field descriptions

 

 

 

 

below). Use the Help button to display information and instructions for

 

 

 

 

each field.

 

Table 3-11

 

 

 

Verify Level 2 Values Field Descriptions

 

 

 

 

 

 

 

 

 

 

k - Level 2

Maximum number of frames that can be

 

 

 

 

Window Size

transmitted without an acknowledgment. The

 

 

 

 

 

range is 1 through 7 for Modulo-8 and 1 through

 

 

 

 

 

127 for Modulo-128. The default is 7. Use the

 

 

 

 

 

value given on your subscription form.

 

 

 

 

 

 

 

 

 

 

T1 -

Maximum number of milliseconds to wait for an

 

 

 

 

Retransmission

acknowledgment before retransmitting a frame.

 

 

 

 

Timer

The range is 100 to 12000. The default is 3000.

 

 

 

 

 

Use the value given on your subscription form.

 

 

 

 

 

 

 

 

 

 

T3 - Idle Timer

Maximum number of milliseconds that a line can

 

 

 

 

 

be idle before it is declared disconnected. This

 

 

 

 

 

value should be greater than or equal to the

 

 

 

 

 

Retransmission Timer (T1) times the

 

 

 

 

 

Retransmission Count (N2). The range is 1000 to

 

 

 

 

 

240000. The default is 60000. Use the value given

 

 

 

 

 

on your subscription form.

 

 

 

 

 

 

 

 

 

 

N1 - Frame Size

Maximum number of octets that can be

 

 

 

 

 

transmitted in a single frame. The range is 149

 

 

 

 

 

(minimum) through 4103. The default is 149.

 

 

 

 

 

 

 

 

 

 

N2 -

Maximum number of times a given frame can be

 

 

 

 

Retransmission

transmitted before an error condition is

 

 

 

 

Count

identified. The range is 0 through 255. The

 

 

 

 

 

default is 20.

 

 

 

 

 

 

 

 

 

 

 

 

NOTE

 

 

 

Because the timer values count the amount of time between

 

 

 

 

unacknowledged frames, you may need to increase the values of T1

 

 

 

 

(Retransmission Timer) and T3 (Idle Timer) if you use Modulo-128 with

 

 

 

 

a window size greater than seven.

 

 

 

 

 

Step

3. Click on OK to return to the “Configure X.25 Card” dialog when you have

 

 

 

 

finished verifying level 2 values.

46

Chapter 3