METHOD TO SIGNAL A FAILURE IN A MIXED PDH/SDH NETWORK IN ORDER TO ENABLE THE LATTER TO PROVIDE A SERVICE SUCH AS A PROTECTION MECHANISM

摘要

To signal a failure in a mixed PDH/SDH network in order to enable this network to provide a service such as a protection mechanism, an alarm indication has to be provided to an SDH node in the event of that failure. A PDH node linked to that SDH node creates an alarm data stream and provides this alarm data stream to the SDH node in the event of any of: - an internal PDH node failure; and - a link failure between the previous node and the PDH node; and - upon reception of such an upstream created alarm data stream; The SDH node creates the alarm indication in the event of any of: - a link failure between the PDH node and the SDH node; and - upon reception of such an alarm data stream coming from the PDH node.