Other ITS Roadway Equipment --> ITS Roadway Equipment:
variable speed limit coordination
This triple is bi-directional. See also
ITS Roadway Equipment --> Other ITS Roadway Equipment: variable speed limit coordination
Definitions
variable speed limit coordination (Information Flow): The direct flow of information between field equipment. This includes information used to configure, control, and monitor variable speed limit systems including the equipment used to provide current speed limits and other information to drivers.
Other ITS Roadway Equipment (Source Physical Object): Representing another set of ITS Roadway Equipment, 'Other ITS Roadway Equipment' supports 'field device' to 'field device' communication and coordination, and provides a source and destination for information that may be exchanged between ITS Roadway Equipment. The interface enables direct coordination between field equipment. Examples include the direct interface between sensors and other roadway devices (e.g., Dynamic Message Signs) and the direct interface between roadway devices (e.g., between a Signal System Master and Signal System Local equipment) or a connection between an arterial signal system master and a ramp meter controller.
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 associated with the following Functional Objects:
This Triple is described by the following Functional View Data Flows:
- fors-variable_speed_limit_control
- fors-variable_speed_limit_display_data
- fors-variable_speed_limit_status
This Triple has the following triple relationships:
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Communication Solutions
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US: NTCIP Message Sign - SNMPv3/TLS (5)
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US: NTCIP Message Sign - SNMPv1/TLS (6)
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(None-Data) - Secure Internet (ITS) (32)
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US: NTCIP Message Sign - SNMPv1 (32)
Selected Solution
US: NTCIP Message Sign - SNMPv1/TLSSolution Description
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ITS Application Entity
NTCIP 1203  |
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Mgmt
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Facilities
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Security
IETF RFC 8446 |
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TransNet
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Access
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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 | Recent |
| Spatial Context | Local |
| Acknowledgement | True |
| Cardinality | Unicast |
| Initiator | Source |
| Authenticable | True |
| Encrypt | True |
| Interoperability | Description |
|---|---|
| Local | In cases where an interface is normally encapsulated by a single stakeholder, interoperability is still desirable, but the motive is vendor independence and the efficiencies and choices that an open standards-based interface provides. |
Security
| Information Flow Security | ||||
|---|---|---|---|---|
| Confidentiality | Integrity | Availability | ||
| Rating | Moderate | Moderate | Moderate | |
| Basis | Any control flow has some confidentiality requirement, as observation of the flow may enable an attacker to analyze and learn how to assume control. MODERATE for most flows as the potential damage is likely contained, though anything that could have a significant safety impact may be assigned HIGH. | Since this directly impacts device control, we consider it the same as a control flow. Control flows, even for seemingly innocent devices, should have MODERATE integrity at minimum, just to guarantee that intended control messages are received. Incorrect, corrupted, intercepted and modified control messages can or will result in target field devices not behaving according to operator intent. The severity of this depends on the type of device, which is why some devices are set MODERATE and some HIGH. | Since this directly impacts device control, we consider it the same as a control flow. Control flow availability is related to the criticality of being able to remotely control the device. For most devices, this is MODERATE. For purely passive devices with no incident relationship, this will be LOW. All devices should have default modes that enable them to operate without backhaul connectivity, so no device warrants a HIGH. | |
| Security Characteristics | Value |
|---|---|
| Authenticable | True |
| Encrypt | True |