Network Time Source --> Connected Vehicle Roadside Equipment:
time

Definition
Included In
Communication Solutions
Characteristics
Security

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).

Connected Vehicle Roadside Equipment (Destination Physical Object): 'Connected Vehicle Roadside Equipment' (CV RSE) represents the Connected Vehicle roadside devices that are used to send messages to, and receive messages from, nearby vehicles using Dedicated Short Range Communications (DSRC) or other alternative wireless communications technologies. Communications with adjacent field equipment and back office centers that monitor and control the RSE are also supported. This device operates from a fixed position and may be permanently deployed or a portable device that is located temporarily in the vicinity of a traffic incident, road construction, or a special event. It includes a processor, data storage, and communications capabilities that support secure communications with passing vehicles, other field equipment, and centers.

Included In

This Triple is in the following Service Packages:

SU05: Location and Time

This triple is associated with the following Functional Objects:

RSE Support Services

This Triple is described by the following Functional View Data Flows:

fnts-external_source_time

This Triple has the following triple relationships:

None

Communication Solutions

NTP - UDP/IP (3)

Solutions are sorted in ascending Gap Severity order. The Gap Severity is the parenthetical number at the end of the solution.

Selected Solution

NTP - UDP/IP

Solution Description

This solution is used within Australia, Canada, the E.U. and the U.S.. It combines standards associated with NTP with those for I-I: UDP/IP. The NTP standards include standards required to reliably set time information in a subsystem. The I-I: UDP/IP standards include lower-layer standards that support the Network Time Protocol that allows NTP servers to provide time synchronization services to other NTP servers and clients.

ITS Application Entity No Standard Needed			Click gap icons for more info.
Mgmt Bundle: NTP Bundle: SNMPv3 MIB	Facilities No Standard Needed	Security (None)
	TransNet IETF RFC 768 IP Alternatives
	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
Time Context	Now
Spatial Context	Local
Acknowledgement	True
Cardinality	Unicast
Initiator	Destination
Authenticable	True
Encrypt	False

Interoperability	Description
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
	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
Authenticable	True
Encrypt	False

Network Time Source --> Connected Vehicle Roadside Equipment:time