A system and method for calculating round trip delay (RTD) values in a switched digital network such as an asynchronous transfer mode (ATM) network. A loopback cell such as an ATM operation and maintenance (OAM) cell is used to carry a delta value through the network. The delta value, which represents...http://www.google.de/patents/US6545979?utm_source=gb-gplus-sharePatent US6545979 - Round trip delay measurement
