3com Corporation

C Paul Douglas

Rajiv Bhatia

Daniel M Brennan

Jyh-Ming J Wang

Suiling C Zhang

Siuling C Zhang

A LAN modem permits unambiguous routing for multiple workstations located on a LAN to each gain access through the LAN modem to any one of a number of different remote servers located on a number of different remote networks using a combination of public port number and public address of the workstation. There are instances where sessions are changed between the same workstation/server. This changing of sessions changes the public port numbers associated with each session, which destroys the above unambiguous routing, since the combination of a public destination IP address and a private destination port number is no longer the same unique value contained in an address translation table of the LAN modem. A four step hierarchical procedure is provided in which the LAN modem determines which workstation the packet is to be routed based upon value of fields stored in the network address translation (NAT) table or value of fields stored in a static table. The NAT table or static table entries are compared to the values of fields stored in the packet header.

Apparatus and methods for determining the correct workstation within a LAN for a LAN modem to route a packet

Apparatus, and accompanying methods for use therein, for an ISDN LAN modem that is suited for small user environments and which contains an internal ISDN router having a self-contained network hub for inter-connecting multiple network devices, such as workstations, to each other through a local area network (LAN) and for permitting each of those devices to each gain access through the router to any one of a number of different remote networks. Through use of a multi-tiered routing hierarchy including both destination- and source-based routing, the LAN modem accommodates several modalities of network communication not heretofore possible in a conventional router. Specifically, several different workstations can simultaneously communicate through the LAN modem with a common remote network and share a single user account at a corresponding network service provider. Also, the LAN modem can simultaneously route packet traffic between multiple workstations on the LAN and different remote networks through different ISDN connections simultaneously existing between the LAN modem and corresponding network service providers.

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Matawan, NJ, United States of America

C Paul Douglas