Cabletron Systems CyberSWITCH CSX150 User Manual

Also see for CyberSWITCH CSX150: User guide Quick start guide

Contents

Small Office Remote Access Switch 183CONFIGURING A LTERNATE ACCESSESX.25 AccessesBEARER CHANNELSA list of bearers (a channel map) that will be used on the line associated with this X.25 access. Therange of channels is from 1 to 2. Separate bearer channels by commas, and/or list a range by usinga dash (-).LAPB C ONFIGURATION ELEMENTSLink Access Protocol-Balanced (LAPB), is a data link layer protocol that is used in X.25 connections.LAPB is based on the HDLC protocol.Note: If you are unsure of any of these values, use the default values where provided.LAPB S EQUENCE N UMBER RANGEThe LAPB sequence number range to use, regular, or extended. Extended sequence numberingallows for frames to be assigned sequence numbers from 0-127 (modulo 128), as opposed to 0-7(modulo 8). Using modulo 128, the DTEs can send up to 127 frames without receiving anacknowledgment. Using modulo 8, the DTEs can send up to 7 frames without receiving anacknowledgment. The default value is modulo 8.TIMER T1This timer defines the maximum time to wait for responses to pending commands. The range forthe T1 timer is 1 to 10 seconds. The default value is 1 second.TIMER T3This timer signals that an excessively long idle time is occurring on the link. LAPB requires thatTimer T3 be greater than Timer T1. The range for the T3 timer is 2 to 20 seconds. The default valueis 10 seconds.M AXIMUM NUMBER OF F RAME R ETRANSMISSIONSThis is the maximum number of frame retransmissions that can be performed (commonly knownas “N2”). If this maximum is exceeded, the link is considered out of order. The range for themaximum number of frame retransmissions is 1 to 5 retransmissions. The default value is 3retransmissions.MAXIMUM NUMBER OF OUTSTANDING FRAMESEnter the maximum number of frames that the transmitting station may have outstanding at anygiven time (commonly known as “K”). The range for this parameter will be 1-7 if the modulo 8sequence numbers are being used for LAPB, or 1-127 if modulo 128 sequence numbers are beingused. The range for the maximum number of outstanding frames is 1 to 7 frames. The default valueis seven frames.