Patent ID: 6442132
Filing Date: 2002-08-27
Classification: H04L,H04Q

Abstract:
A method of maintaining communication, in an asynchronous cell-based digital communications network having a plurality of switching nodes, between first and second endpoints attached to respective endpoint switching nodes during transfer between a primary bi-directional virtual connection established over a first route between said endpoints and a secondary bi-directional virtual connection available over an alternate route through said network, comprising the steps of:establishing a precursor secondary virtual connection between said fit and second endpoints over said alternate route, said precursor secondary virtual connection consisting of unidirectional connections in the receive direction at said endpoint switching nodes and bi-directional connections between said endpoint switching nodes; and progressively switching to said secondary bi-directional virtual connection by sequentially establishing a bi-directional connection at said first endpoint switching node, transmitting cells toward the second endpoint switching node over said alternate, establishing a bi-directional connection at said second endpoint switching node upon receipt of an indication over said alternate route that the first endpoint switching node has transferred to the alternate route, and transmitting cells toward the first endpoint from the second endpoint over the alternate route to complete the transfer of communication between said first and second endpoints to said secondary bi-directional virtual connection.