Link Type: Network Time Protocol
Network Time Source --> ITS Roadway Equipment:
time
Definitions
time (Information Flow): Current time expressed in Universal Time Coordinated (UTC) format from a Stratum-2 time server.
Network Time Source (Source Physical Object): The 'Network Time Source' represents the external time source the Connected Vehicle Service Monitor System uses as the basis for time. This is likely implemented as a Stratum-2 Network Time Server that is 2 steps removed from a basic time source (e.g., atomic clock).
ITS Roadway Equipment (Destination Physical Object): 'ITS Roadway Equipment' represents the ITS equipment that is distributed on and along the roadway that monitors and controls traffic and monitors and manages the roadway. This physical object includes traffic detectors, environmental sensors, traffic signals, highway advisory radios, dynamic message signs, CCTV cameras and video image processing systems, grade crossing warning systems, and ramp metering systems. Lane management systems and barrier systems that control access to transportation infrastructure such as roadways, bridges and tunnels are also included. This object also provides environmental monitoring including sensors that measure road conditions, surface weather, and vehicle emissions. Work zone systems including work zone surveillance, traffic control, driver warning, and work crew safety systems are also included.
Included In
This Triple is in the following Service Packages:
This Triple is in the following Functional Objects:
This Triple is described by the following Functional View Data Flows:
This Triple has the following triple relationships:
None |
Communication Solutions
- NTP - UDP/IP (3)
Selected Solution
Solution Description
ITS Application Entity
No Standard Needed |
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Mgmt
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Facilities
No Standard Needed |
Security
(None) |
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TransNet
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Access
Internet Subnet Alternatives |
Note that some layers might have alternatives, in which case all of the gap icons associated with every alternative may be shown on the diagram, but the solution severity calculations (and resulting ordering of solutions) includes only the issues associated with the default (i.e., best, least severe) alternative.
Characteristics
Characteristic | Value |
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Time Context | Now |
Spatial Context | Local |
Acknowledgement | True |
Cardinality | Unicast |
Initiator | Destination |
Authenticable | True |
Encrypt | False |
Interoperability | Description |
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National | This triple should be implemented consistently within the geopolitical region through which movement is essentially free (e.g., the United States, the European Union). |
Security
Information Flow Security | ||||
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Confidentiality | Integrity | Availability | ||
Rating | Not Applicable | High | Moderate | |
Basis | Time reference is intended to be univerally available. | Time must be highly coordinated for some applications. This support function must meet the highest requirement. | Time coordination must always be in place, but local mechanisms for tracking time should suffice to avoid catastrophic failures for known use cases, thus MODERATE. |
Security Characteristics | Value |
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Authenticable | True |
Encrypt | False |