Patent ID: 7660236
Filing Date: 2010-02-09
Classification: H04J,H04L

Abstract:
1. An automatic protection switching system comprising: a local node for transmitting a first data stream to be protected; and a redundant protection pair of nodes comprising: a first data link that couples the local node to the first remote node; and a second data link that couples the local node to the second remote node; wherein each periodic liveliness message sent on the first control link to said second remote node comprises an I Heard You (IHY) message, the IHY message indicating whether the first remote node received within a duration of a single liveliness message cycle a previously transmitted periodic liveliness message from the second remote node on the second control link, and wherein a protection switching behavior of the second remote node is triggered within substantially a single liveliness message cycle, depends upon the IHY message sent to the second remote node, and prevents duplication of data on the first data link and the second data link by deactivating one of the data links.