3Com Router Command Reference Guide — V1.00Option MeaningSystem view on the X.25 interface.For related commands, see display x25 map, x25 reverse-charge-accept, x25call-facility, x25 timer idle, x25 vc-per-map.Example# Set two mappings on the X.25 interface Serial0 and Serial1 respectively. The attributefor each of the four mappings is different.[3Com]channel interface serial 0[3Com-Serial0]x25 map ip 202.38.160.11 x121-address 20112451reverse-charge-request reverse-charge-accept[3Com-Serial0]x25 map ip 202.38.160.138 x121-address 20112450 packet-size 512512 idle-timer 10[3Com]channel interface serial 1[3Com-Serial1]x25 map ipx 20.30.4.1 x121-address 25112451 window-size 4 4broadcast[3Com-Serial0]x25 map ipx 20.30.4.8 x121-address 25112450 no-callinlogic-channel 65.1.29 x25 moduloSyntaxx25 modulo modulusundo x25 moduloViewInterface viewParametermodulus: modulo size, whose value is 8 or 128. By default, modulo 8 is used..DescriptionUsing the x25 modulo command, you can configure the window modulus of an X.25interface. Using the undo x25 modulo command, you can restore to the default value.The slip window is the basis for X.25 traffic control, and the key about the slip window isthat the sent packets are numbered cyclically in order and are to be acknowledged bythe remote end. The order in numbering refers to the ascending order, like “…2, 3, 4, 5,6…” “Cyclically” means that the numbering starts again from the beginning when acertain number (called modulo) is reached. For example, when the modulo is 8, thenumbering goes “…4, 5, 6, 7, 0, 1…”66
