Patent ID: 11943147
Assignee: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 24:
25. A non-transitory computer readable recording medium storing a computer program product for controlling a node in in a telecommunications system for determining a passive Round Trip Time (RTT) delay for exchanging data packets in accordance with a data transmission protocol between a first device and a second device operatively connected to the telecommunications system, wherein the first device is identified by a first device identification, wherein the second device is identified by a second device identification, wherein the data packets comprise an address part including a source address and a destination address, the computer program product comprising software instructions which, when run on processing circuitry of the node, causes the node to:
receive a data packet including an encrypted payload and originating from the first device and directed to the second device, the address part of the data packet comprising the first device identification as source address and the second device identification as destination address;
modify the first device identification of the source address of the received data packet;
modify the received data packet having an address part comprising the modified first device identification as source address and the second device identification as destination address to provide a modified data packet including the encrypted payload;
link, in an address translation table, the address part of the received data packet with the address part of the modified data packet;
transmit, at a first point in time, the modified data packet to the second device;
receive, at a second point in time and from the second device, a response data packet, the response data packet having an address part comprising the modified first device identification as destination address and the second device identification as source address;
modify the received response data packet having an address part comprising the first device identification as destination address and the second device identification as source address, using the address translation table, to provide a modified response data packet;
transmit the modified response data packet to the first device; and
determine the RTT delay from the first and second points in time.