Cisco IOS Wide-Area Networking Configuration Guide - Free Books

Configuring X.25 and LAPBX.25 and LAPB Configuration Examples• X.29 Access List Example• X.29 Profile Script ExampleTypical LAPB Configuration ExampleIn the following example, the frame size (N1), window size (k), and maximum retransmission (N2)parameters retain their default values. The encapsulation interface configuration command sets DCEoperation to carry a single protocol, IP by default. The lapb t1 interface configuration command sets theretransmission timer to 4,000 milliseconds (4 seconds) for a link with a long delay or slow connectingDTE device.interface serial 3encapsulation lapb dcelapb t1 4000Transparent Bridging for Multiprotocol LAPB Encapsulation ExampleThe following example configures transparent bridging for multiprotocol LAPB encapsulation:no ip routing!interface Ethernet 1no ip addressno mop enabledbridge-group 1!interface serial 0no ip addressencapsulation lapb multibridge-group 1!bridge 1 protocol ieeeTypical X.25 Configuration ExampleThe following example shows the complete configuration for a serial interface connected to acommercial X.25 PDN for routing the IP protocol. The IP subnetwork address 172.25.9.0 has beenassigned for the X.25 network.NoteWhen you are routing IP over X.25, you must treat the X.25 network as a single IP network orsubnetwork. Map entries for routers that have addresses on subnetworks other than the one on which theIP address of the interface is stored are ignored by the routing software. Additionally, all routers usingthe subnet number must have map entries for all other routers. Moreover, using the broadcast option withdynamic routing can result in significantly larger traffic loads, requiring a larger hold queue, largerwindow sizes, or multiple VCs.interface serial 2ip address 172.25.9.1 255.255.255.0!encapsulation X25!! The “bandwidth” command is not part of the X.25! configuration; it is especially important to understand that it does not63