ADTRAN Express 4120 - Manual (Page 39)

Chapter 1. Understanding ISDN and the Express 4110/4120
61200176L3-1 Express 4110/4120 User Manual 1-9
Figure 1-10. SOHO to Corporate LAN (4120)
The Express 4110/4120 provides the following basic functions:
1. LAN Bridge: Bridging provides a point-to-point connection between
two LANs. The bridge learning function scans the source and desti-
nation media access control (MAC) addresses of all packets on its
local LAN and determines which packets should be transmitted over
the ISDN link. Applications include connectivity between single
user or small offices to corporate LANs. The Express 4110/4120 uses
the Spanning Tree Algorithm (IEEE 802.1d-ISO/IEC10038), which
provides a loop-free topology and redundancy.
2. IP Router: The Express 4110/4120 can function as an IP router using
the Routing Information Protocol (RIP) for advertising and learning
routes among other routers. Static routes may also be entered into
the routing table.
3. IPX Router: IPX routers and services can be exchanged between the
Express 4110/4120 and other devices using RIP and Service Advertis-
ing Protocol (SAP). Watch dog serialization filtering and spoofing can
permit the ISDN to be idle during no application traffic periods.