Nortel Networks Corporation

Lee C Himbeault

Paul Andrew Senyshyn

Martin Wollensak

Steven Rhodes

Ronald Wellard

William W Gage

Ken Chow

A distributed PBX, KSU and the like system has at least one time domain multiplexed (TDM) switch unit interfaced with transparent wideband channels such as Ethernet by means of at least one Public Switched Telephone Network (PSTN) interface unit and at least one service module (SM) interconnecting it to remote station terminals. One or more applications servers may be located where available or convenient and interact with the TDM switch unit by means of IP addressable path or paths.

Distributed PBX, KSU and the like system utilizing internet protocol

A node on a collision detection protocol based network forces collisions to gain control of the network when it has real time data that needs to be transferred to another node on the network, and then begins transmitting the real time data prior to other nodes gaining control of the network. Each node which has real time data to transfer keeps track of a maximum wait time parameter to determine when the real time data must be transferred to ensure it arrives at a destination on time. As the maximum wait time is approached, the node forces a collision by transmitting even though it senses another node is already transmitting to force the network into a quiet mode. It then starts transmitting the real time data prior to other nodes beginning transmission.

Data network for real time information

The present invention discloses a method for securely adding a new end station to a local area network (LAN) segmented into a number of virtual local area networks (VLANs). The invention is applicable to various types of LANs such as Ethernet and token ring. The LAN comprises an authentication server (AS) which interacts with each new end station before connection to a VLAN is allowed. The method involves the AS administering a test to the new end station, which may involve prompting the new end station for a password or asking it to encrypt a given number using a secret algorithm known only to the new end station and to the AS. The AS examines the results of this test and determines whether the new end station is permitted to join the VLAN. For added security, the new end station can verify authenticity of the AS by administering a test of its own, which may consist of prompting the AS for a password of its own or asking it to encrypt a new number, the new end station subsequently determining whether the AS is indeed genuine before beginning to transmit any further information. In this way, an end station cannot join a VLAN without authentication by the AS and a legitimate end station can verify whether the test it is asked to pass comes from a legitimate source, thereby avoiding network security breaches.

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Calgary, Canada

Lee C Himbeault