ADTRAN Express L128FP User Manual

ADTRAN Express L128FP User Manual Manual pdf 27 page image

Chapter 1. Understanding IDSL and the Express L128FP61202070L4-20 Express L128FP User Manual 1-5BridgingIn Bridge Mode, the Express L128FP can be used to connect two LANsegments. In this mode, all protocols are supported because they aretransported across the IDSL link at the MAC layer. The Spanning TreeAlgorithm can be used to guarantee a loop-free topology. MAC ad-dresses are “learned” by each Express L128FP to prevent non-WANpackets from being bridged.IP RoutingThe Express L128FP operates as an IP router when the Configuration/IP/IP Router/Mode option is configured to On. In PPP mode, the Ex-press L128FP uses an IP unnumbered WAN interface; the IP addressand mask assigned to the unit’s LAN interface apply to all routing andIP operations for the unit. In Frame Relay mode, each PVC can bespecified as numbered or unnumbered links. If a default gateway isspecified on the network of the Ethernet interface, the unit attempts toreach the gateway through that interface. If no default gateway isspecified (i.e., 0.0.0.0) the WAN interface becomes the default gateway(recommended for remote applications when there are no other rout-ers on the remote LAN).IPX RoutingNetwork routes and services are learned and advertised using Nov-ell’s RIP and SAP.Concurrent Routing And BridgingThe Express L128FP can route IP and IPX as well as bridge non-IP/IPXpackets simultaneously. The PPP profile will by default negotiate PPPnetwork protocols to support the transmission and reception of IP,IPX, and Bridge packets. If the PPP peer does not accept a protocol, theExpress L128FP will fall back to any combination of routing andbridging.