Safety extension for precision time protocol (PTP)
A network element, for use in an automotive network in a vehicle, includes one or more ports, packet processing circuitry and a validation data collector. The one or more ports are configured for communicating over the automotive network in the vehicle. The packet processing circuitry is configured to receive packets from the automotive network via the one or more ports, the packets including time-protocol packets, to process the received packets, and to forward the processed packets to the automotive network via the one or more ports. The validation data collector is configured to derive, from at least some of the time-protocol packets that are processed by the packet-processing circuitry, validation data indicative of compliance of the network element with a vehicle-safety requirement, and to make the validation data accessible from outside the network element.
1. A network element for use in an automotive network, the automotive network being disposed within a vehicle, the network element comprising:
one or more ports for communicating with other network elements of the vehicle over the automotive network in the vehicle;
packet processing circuitry, configured to:
receive packets from electronic subsystems of the vehicle via the one or more ports, the packets including time-protocol packets carrying time-stamps in accordance with a time protocol used for synchronizing the electronic subsystems to a common time-base,
process the received packets, including adding (i) time delays incurred over links over which the time-protocol packets were received and (ii) time delays incurred by the network element to values of the timestamps in the received packets, and forwarding the processed packets to the electronic subsystems of the vehicle via the one or more ports; and
a validation data collector, configured to derive, from at least some of the time-stamp of at least some of the time-protocol packets processed by the packet-processing circuitry and used for synchronizing the electronic subsystems, validation data indicative of compliance of the network element with a vehicle-safety requirement, and to make the validation data accessible from outside the network element.
2. The network element according to claim 1 , wherein the validation data collector is configured to derive and export validation records comprising one or more of:
one or more of the time-stamps extracted from the at least some of the time-protocol packets processed by the packet processing circuitry;
one or more parameters of the one or more ports used for communicating the at least some of the time-protocol packets processed by the packet processing circuitry; and
error events relating to the at least some of the time protocol packets processed by the packet processing circuitry.
3. The network element according to claim 1 , wherein the time-protocol packets comprise Precision Time Protocol (PTP) packets.
4. The network element according to claim 1 , wherein the validation data collector is configured to store the validation data in a memory, and to provide at least part of the validation data in response to a request from outside the network element.
5. The network element according to claim 1 , wherein the validation data collector is configured to transmit at least part of the validation data from the network element, irrespective of any request from outside the network element.
6. A safety validation apparatus for use in a vehicle, the apparatus comprising:
an interface for communicating at least with a network element of an automotive network, the automotive network disposed within the vehicle; and
a validation processor, configured to
obtain from the network element validation data derived from time-stamps carried in time-protocol packets processed by the network element, wherein the time-protocol packets carry the time-stamps in accordance with a time protocol used for synchronizing electronic subsystems of the vehicle to a common time-base, the timestamps carried by at least some of the time-protocol packets having been set by the network device by adding
(i) time delays incurred over links over which the time-protocol packets were received and (ii) time delays incurred by the network element, to values of the timestamps in the at least some of the time protocol packets entering the network
element, and wherein the validation processor is and to verify, based on the validation data, that the network element complies with a vehicle-safety requirement.
7. The safety validation apparatus according to claim 6 , wherein the validation processor is configured to verify that the network element complies with the vehicle-safety requirement by verifying an accuracy of one or more of the time-stamps in the time-protocol packets.
8. The safety validation apparatus according to claim 6 , wherein the validation processor is configured to verify that the network element complies with the vehicle-safety requirement by verifying that a temporal pattern of the time-protocol packets matches an expected pattern.
9. The safety validation apparatus according to claim 6 , wherein the validation processor is configured to verify that the network element complies with the vehicle-safety requirement by verifying a topology of the automotive network.
10. A method for use in a network element of an automotive network, the automotive network disposed within a vehicle, the method comprising:
receiving in the network element packets, the packets including time-protocol packets carrying time-stamps in accordance with a time protocol used for synchronizing electronic subsystems of the vehicle to a common time-base,
processing the received packets, including adding (i) time delays incurred over links over which the time-protocol packets were received and (ii) time delays incurred by the network element to values of the timestamps in the received packets, and forwarding the processed packets to the electronic subsystems of the vehicle;
deriving in the network element, from at least some of the time-stamps of at least some of the time-protocol packets processed by the network element and used for synchronizing the electronic subsystems, validation data indicative of compliance of the network element with a vehicle-safety requirement; and
making the validation data accessible from outside the network element.
11. The method according to claim 10 , wherein deriving and the validation data accessible comprises deriving exporting validation records comprising one or more of:
one or more of the time-stamps extracted from the at least some of the processed time-protocol packets;
one or more parameters of one or more ports of the network element used for communicating the at least some of the processed time-protocol packets; and
error events relating to the at least some of the processed time-protocol packets.
12. The method according to claim 10 , wherein the time-protocol packets comprise Precision Time Protocol (PTP) packets.
13. The method according to claim 10 , wherein making the validation data accessible comprises storing the validation data in a memory, and providing at least part of the validation data in response to a request from outside the network element.
14. The method according to claim 10 , wherein making the validation data accessible comprises transmitting at least part of the validation data from the network element, irrespective of any request from outside the network element.
15. A safety validation method for use in a vehicle, the method comprising:
obtaining, from a network element of an automotive network, the automotive network disposed within the vehicle, validation data derived from time-stamps carried in time-protocol packets processed by the network element, wherein the time-protocol packets carry the time-stamps in accordance with a time protocol used for synchronizing the electronic subsystems to a common time-base,
wherein the timestamps carried by at least some of the time-protocol packets have been set by the network device by adding (i) time delays incurred over links over which the time-
protocol packets were received and (ii) time delays incurred by the network element to values of the timestamps in the at least some of the time protocol packets entering the network element;
and
verifying, based on the validation data, that the network element complies with a vehicle-safety requirement.
16. The safety validation method according to claim 15 , wherein verifying that the network element complies with the vehicle-safety requirement comprises verifying an accuracy of one or more of the timestamps in the time-protocol packets.
17. The safety validation method according to claim 15 , wherein verifying that the network element complies with the vehicle-safety requirement comprises verifying that a temporal pattern of the time-protocol packets matches an expected pattern.
18. The safety validation method according to claim 15 , wherein verifying that the network element complies with the vehicle-safety requirement comprises verifying a topology of the automotive network.