Cabletron Systems CSX1200, CSX1000 manual Accesses

CONFIGURING ALTERNATE ACCESSES

X.25 Accesses

7.Enter a list of bearers (a channel map). For PRI lines, the range of channels is from 1 to 24. For BRI lines, the range of channels is from 1 to 2. Separate bearer channels by commas, and/or list a range by using a dash (-).

LAPB CONFIGURATION INFORMATION

Note: You will not be prompted for this information if you are using X.25 over a D-Channel. The system will “know” what type of X.25 access you are using by the line you selected for the access. If you select a line that has its data link configured to support X.25 communications, then you are selecting a line that will do X.25 over a D-Channel.

1.Enter the LAPB sequence number range to use, regular, or extended. Extended sequence numbering allows for frames to be assigned sequence numbers from 0-127 (modulo 128), as opposed to 0-7 (modulo 8).

2.Enter the duration of Timer T1, which is the maximum time to wait for responses to pending commands.

3.Enter the duration of Timer T3, which is used to signal that an excessively long idle time is occurring on the link. LAPB requires that Timer T3 be greater than Timer T1.

4.Enter the maximum number of frame re-transmissions that can be performed (this is commonly known as “N2”).

5.Enter the maximum number of frames that the transmitting station may have outstanding at any given time (this is commonly known as “K”). The range for this parameter will be 1-7 if the Modulo 8 sequence numbers are being used for LAPB, or 1-127 if Modulo 128 sequence numbers are being used.

X.25 CONFIGURATION INFORMATION

1.Configure the X.25 Logical Channel Assignments. This requires entering the maximum number of PVCs and SVCs to be supported. For X.25 over B-channel, a total of 48 virtual circuits are supported; over D-channel 8 virtual circuits are supported. Therefore, the total number of PVCs and SVCs combined cannot exceed the maximum number of VCs.

a.Enter the maximum number of PVCs to support.

b.Enter the maximum number of SVCs to support.

2.Configure the X.25 Timers.

a.Enter the duration of Timer T20.

This timer designates the time limit in which a restart confirmation must be returned by the DCE (the PPSN) after a restart request has been issued by the DTE (the CyberSWITCH).

b.Enter the duration of Timer T21.

This timer designates the time limit in which a call connected response must be returned by the DCE (the PPSN) after a call request has been issued by the DTE (the CyberSWITCH).

c.Enter the duration of Timer T22.

This timer designates the time limit in which a reset confirmation must be returned by the DCE (the PPSN) after a reset request has been issued by the DTE (the CyberSWITCH).

d.Enter the duration of Timer T23.

This timer designates the time limit in which a clear confirmation must be returned by the DCE (the PPSN) after a clear request has been issued by the DTE (the CyberSWITCH).

Workgroup Remote Access Switch 199