4.4. Basic structure

Unicode (ISO 10646) and UTF-8 are used for all messages.

Parsing needs to be performed case sensitive.

All enum values (e.g. Alarm status) must use the exact casing stated in this specification.

Empty values are sent as “” for simple values and as [] for arrays. Optional values can be omitted, but can not be sent as null unless otherwise stated.

In the following example the message type is an alarm message.

{
    "mType": "rSMsg",
    "type": "Alarm",
    "mId": "E68A0010-C336-41ac-BD58-5C80A72C7092",
    "ntsOId": "F+40100=416CG100",
    "xNId": "23055",
    "cId": "AB+84001=860SG001",
    "aCId": "A0001",
    "xACId": "Serious lamp error",
    "xNACId": "3143",
    "aSp": "Issue",
    "ack": "notAcknowledged",
    "aS": "Active",
    "sS": "notSuspended",
    "aTs": "2009-10-01T11:59:31.571Z",
    "cat": "D",
    "pri": "2",
    "rvs": [
        {
            "n": "color",
            "v": "red"
        }
    ]
}

JSon code 2: An RSMP message

The following table is describing the variable content of all message types.

Table 4.2 Variable content

Element	Value	Description
mType	rSMsg	RSMP identifier
type	Alarm	Alarm message
	AggregatedStatus	Aggregated status message
	AggregatedStatusRequest	Aggregated status request message
	StatusRequest	Status message. Request status
	StatusResponse	Status message. Status response
	StatusSubscribe	Status message. Start subscription
	StatusUpdate	Status message. Update of status
	StatusUnsubscribe	Status message. End subscription
	CommandRequest	Command message. Request command
	CommandResponse	Command message. Response of command
	MessageAck	Message acknowledegment. Successful
	MessageNotAck	Message acknowledegment. Unsuccessful
	Version	RSMP / SXL version message
	Watchdog	Watchdog message
mId (or) oMId	(GUID)	Message identity

Note

• mId is a generated GUID (Globally unique identifier) in the equipment that sent the message

• mId is used in all messages as a reference for the message ack

• oMId is used in the message ack to refer to the message which is being acked

• Only version 4 of Leach-Salz UUID is used for the GUID

• Each message sent should have a new GUID, even if the message is resent or the content is the same

The following table describes the variable content in all message types which is defined by the signal exchange list (SXL), except version messages, message acknowledgement messages and watchdog messages.

Table 4.3 Variable content

Element	Description
ntsOId	Component ID for the NTS object
xNId	External NTS id
cId	Component ID

4.4.1. Alarm messages

An alarm message is sent to the supervision system when:

• An alarm becomes active / inactive

• An alarm is requested

• An alarm is acknowledged

• An alarm is being suspended / un-suspended

An acknowledgment of an alarm does not cause a single alarm event to be acknowledged but all alarm events for the specific component with the associated alarm code id. This approach simplifies both in implementation but also in handling - if many alarms occur on the same equipment with short time intervals.

The ability to request an alarms is used in case the supervision system looses track of the latest state of the alarms.

A suspend of an alarm causes all alarms from the specific component with the associated alarm code id to be suspended. This means that alarm messages stops being sent from the site as long as the suspension is active. As soon as the suspension is inactivated alarms can be sent again.

Suspending alarms does not affect alarm acknowledgment. This means that when unsuspending an alarm an alarm can be inactive and not acknowledged.

Alarm messages are event driven and sent to the supervision system when the alarm occurs. Acknowledgement of alarms and alarm suspend messages are interaction driven.

Alarm events are referring to ‘active’ (aSp:Issue), ‘suspended’ (aSp:Suspend) and ‘acknowledged’ (aSp:Acknowledged).

The timestamp (aTs) reflects the individual event according to the element ‘aSp’.

4.4.1.1. Message structure

4.4.1.1.1. Structure of an alarm message

An alarm message has the structure according to the example below.

{
    "mType": "rSMsg",
    "type": "Alarm",
    "mId": "E68A0010-C336-41ac-BD58-5C80A72C7092",
    "ntsOId": "F+40100=416CG100",
    "xNId": "23055",
    "cId": "AB+84001=860SG001",
    "aCId": "A0001",
    "xACId": "Serious lamp error",
    "xNACId": "3143",
    "aSp": "Issue",
    "ack": "notAcknowledged",
    "aS": "Active",
    "sS": "notSuspended",
    "aTs": "2009-10-01T11:59:31.571Z",
    "cat": "D",
    "pri": "2",
    "rvs": [
        {
            "n": "color",
            "v": "red"
        }
    ]
}

JSon code 3: An alarm message

The following table describes the variable content of the message which is defined by the SXL.

Table 4.4 Alarm message

Element	Description
aCId	Alarm code id
xACId	External alarm code id
xNACId	External NTS alarm code id

The following table describes additional variable content of the message.

Table 4.5 Alarm status change

Element	Value	Origin	Description
aSp	Issue	Site	An alarm becomes active/inactive.
	Request	Supervision system	Request the current state of an alarm
	Acknowledge	Supervision system	Acknowledge an alarm
		Site	An alarm becomes acknowledged.
	Suspend	Supervision system	Suspend an alarm
		Site	An alarm becomes suspended/unsuspended
	Resume	Supervision system	Unsuspend an alarm

4.4.1.1.2. Alarm status

Alarm status are only used by alarm messages (not by alarm acknowledgement or alarm suspend messages).

Table 4.6 Alarm status

Element	Value	Description
ack	Acknowledged	The alarm is acknowledged
	notAcknowledged	The alarm is not acknowledged
aS	inActive	The alarm is inactive
	Active	The alarm is active
sS	Suspended	The alarm is suspended
	notSuspended	The alarm is not suspended
aTs	(timestamp)	Timestamp for when the alarm changes status. See the contents of aSp to determine which type of timestamp is used - aSp: Issue: When the alarm gets active or inactive - aSp: Acknowledge: When the alarm gets acknowledged or not acknowledged - aSp: Suspend: When the alarm gets suspended or not suspended All timestamps are set at the local level (and not in the supervision system) when the alarm occurs (and not when the message is sent). See also the data type section.

Fig. 4.1 show possible transitions between different alarm states.

Continuous lines defines possible alarm status changes controlled by logic and dashed lines defines possible changes controlled by user.

Fig. 4.1 Alarm transitions

Alarms should not be sent unless:

• Alarms are unblocked and it’s state changes

• Alarms are sent as part of Communication establishment between sites and supervision system

• Alarms are explicitly requested using Structure for an alarm request message

The following table describes the variable content of the message which is defined by the SXL.

Table 4.7 Alarm status details defined by SXL

Element	Description
cat	Alarm category
pri	Alarm priority

4.4.1.1.3. Return values

Return values (“rvs”) are used by alarm messages (but not by alarm acknowledgment or alarm suspend messages) and is always sent but can be empty (i.e. []) if no return values are defined.

Table 4.8 Alarm return values

Element	Value	Description
rvs	(array)	Return values. Contains the element n and v in an array

The following table describes the content for each return value which is defined by the signal exchange list (SXL).

Table 4.9 Return values

Element	Description
n	Name of the return value
v	Value from equipment

4.4.1.1.4. Structure for an alarm request message

An alarm request message has the structure according to the example below.

{
     "mType": "rSMsg",
     "type": "Alarm",
     "mId": "3d2a0097-f91c-4249-956b-dac702545b8f",
     "ntsOId": "",
     "xNId": "",
     "cId": "AB+84001=860VA001",
     "aCId": "A0004",
     "xACId": "",
     "xNACId": "",
     "aSp": "Request"
}

JSon code 4: An alarm request message

4.4.1.1.5. Structure for an alarm acknowledgement message

An alarm acknowledgement message has the structure according to the example below.

{
     "mType": "rSMsg",
     "type": "Alarm",
     "mId": "3d2a0097-f91c-4249-956b-dac702545b8f",
     "ntsOId": "",
     "xNId": "",
     "cId": "AB+84001=860VA001",
     "aCId": "A0004",
     "xACId": "",
     "xNACId": "",
     "aSp": "Acknowledge"
}

JSon code 5: An alarm acknowledgement message which acknowledges an alarm

An alarm acknowledgement response message has the structure according to the example below.

{
     "mType": "rSMsg",
     "type": "Alarm",
     "mId": "f6843ac0-40a0-424e-8ddf-d109f4cfe487",
     "ntsOId": "",
     "xNId": "",
     "cId": "AB+84001=860VA001",
     "aCId": "A0004",
     "xACId": "",
     "xNACId": "",
     "aSp": "Acknowledge",
     "ack": "Acknowledged",
     "aS": "Active",
     "sS": "notSuspended",
     "aTs": "2015-05-29T08:55:04.691Z",
     "cat": "D",
     "pri": "3",
     "rvs": [
         {
             "n": "Temp",
             "v": "-18.5"
         }
     ]
}

JSon code 6: Response of an alarm acknowledgement message

4.4.1.1.6. Structure for an alarm suspend message

An alarm suspend message has the structure according to the example below.

{
     "mType": "rSMsg",
     "type": "Alarm",
     "mId": "b6579d6d-3a9d-4169-b777-f094946a863e",
     "ntsOId": "",
     "xNId": "",
     "cId": "AB+84001=860VA001",
     "aCId": "A0004",
     "xACId": "",
     "xNACId": "",
     "aSp": "Suspend"
}

JSon code 7: Suspending an alarm using an alarm suspend message

{
     "mType": "rSMsg",
     "type": "Alarm",
     "mId": "2ea7edfc-8e3a-4765-85e7-db844c4702a0",
     "ntsOId": "",
     "xNId": "",
     "cId": "AB+84001=860VA001",
     "aCId": "A0004",
     "xACId": "",
     "xNACId": "",
     "aSp": "Suspend",
     "ack": "Acknowledged",
     "aS": "Active",
     "sS": "Suspended",
     "aTs": "2015-05-29T08:56:25.390Z",
     "cat": "D",
     "pri": "3",
     "rvs": [
         {
             "n": "Temp",
             "v": "-18.5"
         }
     ]
}

JSon code 8: Response of alarm suspend message

{
     "mType": "rSMsg",
     "type": "Alarm",
     "mId": "2a744145-403a-423f-ba80-f38e283a778e",
     "ntsOId": "",
     "xNId": "",
     "cId": "AB+84001=860VA001",
     "aCId": "A0004",
     "xACId": "",
     "xNACId": "",
     "aSp": "Resume"
}

JSon code 9: Resuming an alarm using an alarm suspend message

{
     "mType": "rSMsg",
     "type": "Alarm",
     "mId": "3313526e-b744-434a-b4dd-0cfa956512e0",
     "ntsOId": "",
     "xNId": "",
     "cId": "AB+84001=860VA001",
     "aCId": "A0004",
     "xACId": "",
     "xNACId": "",
     "aSp": "Suspend",
     "ack": "Acknowledged",
     "aS": "Active",
     "sS": "notSuspended",
     "aTs": "2015-05-29T08:58:28.166Z",
     "cat": "D",
     "pri": "3",
     "rvs": [
         {
             "n": "Temp",
             "v": "-18.5"
         }
     ]
}

JSon code 10: Response of a resume message

Allowed content in alarm suspend message is the same as for alarm messages (See Structure of an alarm message) with the exception for alarm status (See Alarm status) and (See Return values).

4.4.1.2. Message exchange between site and supervision system

Message acknowledgement (see section Message acknowledgement) is implicit in the following figures.

An alarm is active/inactive

1. An alarm message is sent to supervision system with the status of the alarm (the alarm is active/inactive)

An alarm is requested

1. An alarm is requested from the supervision system

2. An alarm message is sent to supervision system with the status of the alarm

An alarm is acknowledged at the supervision system

1. An alarm acknowledgement message is sent to the site

2. An alarm message is sent to the supervision system (that the alarm is acknowledged)

An alarm is acknowledged at the site

1. An alarm message is being sent to the supervision system with the status of the alarm (that the alarm is acknowledged)

An alarm is suspended/unsuspended from the supervision system

1. An alarm suspend message is being sent to the site

2. An alarm message is sent to the supervision system with the status of the alarm (that the suspension is activated/deactivated)

An alarm is suspended/unsuspended from the site

1. An alarm message is sent to the supervision system with the status of the alarm (that suspension is activated/deactivated)

4.4.2. Aggregated status message

This type of message is sent to the supervision system to inform about the status of the site. The aggregated status applies to the component which is defined by ComponentType in the signal exchange list. If no component is defined then no aggregated status message is sent.

Aggregated status message are interaction driven and are sent if state, functional position or functional status are changed at the site.

4.4.2.1. Message structure

An aggregated status message has the structure according to the example below.

{
     "mType": "rSMsg",
     "type": "AggregatedStatus",
     "mId": "be12ab9a-800c-4c19-8c50-adf832f22420",
     "ntsOId": "O+14439=481WA001",
     "xNId": "",
     "cId": "O+14439=481WA001",
     "aSTS": "2015-06-08T08:05:06.584Z",
     "fP": null,
     "fS": null,
     "se": [
             true,false,false,false,false,false,false,false
           ]
}

JSon code 11: An aggregated status message

The following tables are describing the variable content of the message:

Table 4.10 Aggregated status

Element	Value	Description
aSTS	(timestamp)	Timestamp for the aggregated status. All timestamps are set at the site (and not in the supervision system) when the event occurs (and not when the message is sent). See also the data type section.

The following table describes the variable content defined by the signal exchange list (SXL).

Table 4.11 Aggregated status SXL content

Element	Description
fP	Functional position
fS	Functional state
se	Array of eight booleans. See State bits

fP and fS is set to null or empty string if no value is defined in the SXL.

4.4.2.1.1. State bits

State bits se is an array of eight booleans, with the meaning defined below. The signal exchange list (SXL) for a particular type of equipment can detail the interpretation of each bit, but is not allowed to change the fundamental meaning or modify the rules for which bits can or must be set together.

Table 4.12 State bits

Bit	Status	Description	Color
1	Local	The site is controlled locally
2	Disconnected	Connection lost (not used by sites)
3	Error	The site has one or more alarm with priority 1
4	Warning	The site has one or more alarm with priority 2
5	Notice	The site has one or more alarm with priority 3
6	Active	The site is in active mode
7	Idle	The site is in idle mode
8	Not configured	Connection not configured (not used by sites)

Bit 1: Local

In case equipment require on-street maintenance it might be necessary to override operating modes for safety or testing purposes. For example, the site might be put in idle mode. When local overrides are active, the site is in local control and this bit is set.

Bit 2: Disconnected (not used by sites)

Set by supervisor when reporting that connection to a site was lost. Not used by sites, which must always clear this bit.

Bit 3: Error

Set if one or more alarm with priority 1 (high) is active.

Bit 4: Warning

Set if one or more alarm with priority 2 (medium) is active.

Bit 5: Notice

Set if one or more alarm with priority 3 (low) is active.

Bit 6: Active

Set if the site is in active mode, i.e. intended to operate normally. This bit is unaffected by alarms and can be set at the same time as bits 3, 4 and 5. A site can be either in active or idle mode, not both, so bits 6 and 7 cannot both be set at the same time.

Bit 7: Idle

Set if the site is in idle mode, meaning it is turned on but not in active use. For example, a traffic light controller in idle mode might have all lamps turned off or in flashing yellow. This bit is unaffected by alarms and can be set at the same time as bits 3, 4 and 5. A site can be either in active or idle mode, not both, so bits 6 and 7 cannot both be set at the same time.

Bit 8: Not configured

Set by supervisors when reporting that connection to a site is not configured. Not used by sites, which must always clear this bit.

Alarm priorities

For more details about alarm priorities, please see section Alarm priority.

4.4.3. Aggregated status request message

This type of message is sent from the supervision system to request the latest aggregated status, in case the supervision system has lost track of the current status.

4.4.3.1. Message structure

An aggregated status request message has the structure according to the example below.

{
     "mType": "rSMsg",
     "type": "AggregatedStatusRequest",
     "mId": "be12ab9a-800c-4c19-8c50-adf832f22425",
     "ntsOId": "O+14439=481WA001",
     "xNId": "",
     "cId": "O+14439=481WA001",
}

JSon code 12: An aggregated status request message

4.4.3.2. Message exchange between site and supervision system

Message acknowledgement (see section Message acknowledgement) is implicit in the following figures.

Functional state, functional position or state booleans changes at the site

1. An aggregated status message is sent to the supervision system.

The supervision system request aggregated status

1. An aggregated status request message is sent to the site.

2. An aggregated status message is sent to the supervision system.

4.4.4. Status Messages

The status message is a type of message that is sent to the supervision system or other equipment with the value of one or more requested statuses, for the referenced component.

The status message can both be interaction driven or event driver and can be sent during the following prerequisites:

• When status is requested from the supervision system or other equipment.

• According to subscription – either by using a fixed time interval or when the status changes.

4.4.4.1. Message structure

4.4.4.1.1. Structure of a status request

A status request message has the structure according to the example below.

{
     "mType": "rSMsg",
     "type": "StatusRequest",
     "mId": "f1a13213-b90a-4abc-8953-2b8142923c55",
     "ntsOId": "O+14439=481WA001",
     "xNId": "",
     "cId": "O+14439=481WA001",
     "sS": [
         {
             "sCI": "S0003",
             "n": "inputstatus"
         },{
             "sCI": "S0003",
             "n": "extendedinputstatus"
         }
     ]
}

JSon code 13: A status request message

The status code id (sCI) and name (n) are placed in an array (sS) in order to enable support for requesting multiple statuses at once.

The following table is describing the variable content of the message.

Table 4.13 Status request

Element	Description
sCI	Status code id
n	Name of the return value

4.4.4.1.2. Structure for a status response message

A status response message has the structure according to the example below.

The status code id (sCI) and name (n) are placed in an array (sS) in order to enable support for responding to multiple statuses at once. The following table is describing the variable content of the message.

{
     "mType": "rSMsg",
     "type": "StatusResponse",
     "mId": "0a95e463-192a-4dd7-8b57-d2c2da636584",
     "ntsOId": "O+14439=481WA001",
     "xNId": "",
     "cId": "O+14439=481WA001",
     "sTs": "2015-06-08T09:15:18.266Z",
     "sS": [
         {
             "sCI": "S0003",
             "n": "inputstatus",
             "s": "100101",
             "q": "recent"
         },{
             "sCI": "S0003",
             "n": "extendedinputstatus",
             "s": "100100101",
             "q": "recent"
         }
    ]
}

JSon code 14: A status response message

The following table is describing the variable content of the message:

Table 4.14 Status response

Element	Value	Description
sTs	(timestamp)	Timestamp

All timestamps are set at the site (and not in the supervision system) when the status is fetched (and not when the message is sent). See also the data type section.

4.4.4.1.3. Return values (returnvalue)

Return values (“sS”) are always sent but can be empty if no return values exists.

Table 4.15 Return values (returnvalue)

Element	Value	Description
sS	(array)	Return values. Contains the elements “sCI”, “s”, “n” and “q” in an array.

Table 4.16 Return values

Element	Description
sCI	Status code id
n	Name of the return value
s	Value from equipment

The following table describes additional variable content of the message.

Table 4.17 Return value quality

Element	Value	Description
q	recent	The value is up to date
	old	The value is not up to date. Used when sending buffered values
	undefined	The component does not exist
	unknown	The value is unknown

If the component does not exist or the value s is unknown then:

• Subscription will not be performed

• q is set according to the table above

• s must be set to null

4.4.4.1.4. Structure for a status subscription request message

A message with the request of subscription to a status has the structure according to the example below. The message is used for constructing a list of subscriptions of statuses, digital and analogue values and events that are desirable to send to supervision system, e.g. temperature, wind speed, power consumption, manual control.

{
     "mType": "rSMsg",
     "type": "StatusSubscribe",
     "mId": "d6d97f8b-e9db-4572-8084-70b55e312584",
     "ntsOId": "O+14439=481WA001",
     "xNId": "",
     "cId": "O+14439=481WA001",
     "sS": [
         {
             "sCI": "S0001",
             "n": "signalgroupstatus",
             "uRt": "5",
             "sOc": false
         },{
             "sCI": "S0001",
             "n": "cyclecounter",
             "uRt": "5",
             "sOc": false
         },{
             "sCI": "S0001",
             "n": "basecyclecounter",
             "uRt": "5",
             "sOc": false
         },{
             "sCI": "S0001",
             "n": "stage",
             "uRt": "5",
             "sOc": false
         }
     ]
}

JSon code 15: A status subscribe message

The following table is describing the variable content of the message:

Table 4.18 Status Request

Element	Type	Description
uRt	number_as_string	updateRate
sOc	boolean	sendOnChange

The updateRate uRt and sendOnChange sOc determines when a status update should be sent.

The following applies:

• updateRate defines a specific interval when to send updates. Defined in seconds with decimals, e.g. “2.5” for 2.5 seconds.

• If updateRate is set to 0 it means that no update is sent using an interval.

• sendOnChange defines if an status update should be sent as soon as the value changes. Note that an SXL can define when an attribute is updated, e.g. a timestamp might only update when another attribute changes.

• It is possible to combine updateRate and sendOnChange to send an update when the value changes and at the same time using a specific interval.

• If updateRate and sendOnChange=true are combined, the updateRate timer is reset when the value changes. For example, if updateRate is set to 5 seconds but the value changes after 2 seconds (triggering sendOnChange) the updateRate timer starts over and waits another 5 seconds to trigger.

• It is not valid to set updateRate=0 and sendOnChange=false since it means that no subscription updates will be sent.

• It is allowed to change updateRate and sendOnChange by sending a new StatusSubscribe during an active subscription.

4.4.4.1.5. Attribute updates

When you set sendOnChange to true you will get an update whenever that attribute changes. However, the SXL can define when a particular attribute is updated. For example, a traffic light that report changes to signal groups might need to include a precise timestamp that indicates when in the cycle the change happened. But even though the cycle counter updates continuously, this should not in itself trigger an update. Instead the cycle counter should be sent along when the signal group state changes. In this case the SXL can define that the cycle counter is updated only when the signal group state changes.

4.4.4.1.6. Structure for a status update message

The status update message is an answer to a request for status subscription. It has the structure according to the example below.

The following applies:

• A StatusUpdate is always sent immediately after subscription request, unless the subscription is already active. The reason for sending the response immediately is because subscriptions usually are established shortly after RSMP connection establishment and the supervision system needs to update with the current statuses.

• If an subscription is already active then the site must not establish a new subscription but use the existing one. It’s allowed to change updateRate and sendOnChange.

{
     "mType": "rSMsg",
     "type": "StatusUpdate",
     "mId": "dabb67f9-2601-4db9-bb8a-c7c47f57e100",
     "ntsOId": "O+14439=481WA001",
     "xNId": "",
     "cId": "O+14439=481WA001",
     "sTs": "2015-06-08T09:33:04.735Z",
     "sS": [
         {
             "sCI": "S0001",
             "n": "signalgroupstatus",
             "s": "A021BC01",
             "q": "recent"
         },{
             "sCI": "S0001",
             "n": "cyclecounter",
             "s": "20",
             "q": "recent"
         },{
             "sCI": "S0001",
             "n": "basecyclecounter",
             "s": "10",
             "q": "recent"
         },{
             "sCI": "S0001",
             "n": "stage",
             "s": "1",
             "q": "recent"
         }
     ]
}

JSon code 16: A status update message

The allowed content is described in Table Status response and Return values.

Since different UpdateRate can be defined for different components it means that partial StatusUpdates can be sent.

{
     "mType": "rSMsg",
     "type": "StatusSubscribe",
     "mId": "6bbcb26e-78fe-4517-9e3d-8bb4f972c076",
     "ntsOId": "",
     "xNId": "",
     "cId": "O+14439=481WA001",
     "sS": [
         {
             "sCI": "S0096",
             "n": "hour",
             "uRt": "120",
             "sOc": false
         },{
             "sCI": "S0096",
             "n": "minute",
             "uRt": "60",
             "sOc": false
         }
     ]
}

JSon code 17: A subscription request to subscribe to statues with different update rates

{
     "mType": "rSMsg",
     "type": "StatusUpdate",
     "mId": "b6bd7c96-f150-4756-9752-47a661e116db",
     "ntsOId": "",
     "xNId": "",
     "cId": "O+14439=481WA001",
     "sTs": "2015-05-29T13:47:56.740Z",
     "sS": [
         {
             "sCI": "S0096",
             "n": "minute",
             "s": "47",
             "q": "recent"
         }
     ]
}

JSon code 18: A partial status update. Only a single status is updated

4.4.4.1.7. Structure for a status unsubscription message

A message with the request of unsubscription to a status has the structure according to the example below. The request unsubscribes on one or several statuses. No particular answer is sent for this request, other than the usual message acknowledgement.

{
     "mType": "rSMsg",
     "type": "StatusUnsubscribe",
     "mId": "5ff528c5-f2f0-4bc4-a335-280c52b6e6d8",
     "ntsOId": "O+14439=481WA001",
     "xNId": "",
     "cId": "O+14439=481WA001",
     "sS": [
         {
             "sCI": "S0001",
             "n": "signalgroupstatus"
         },{
             "sCI": "S0001",
             "n": "cyclecounter"
         },{
             "sCI": "S0001",
             "n": "basecyclecounter"
         },{
             "sCI": "S0001",
             "n": "stage"
         }
     ]
}

JSon code 19: A status unsubscribe message

The allowed content is described in Table Status Request

4.4.4.2. Message exchange between site and supervision system/other equipment - request

Message acknowledgement (see section Message acknowledgement) is implicit in the following figure.

1. Status request

2. Status response

4.4.4.3. Message exchange between site and supervision system/other equipment - subscription

Message acknowledgement (see section Message acknowledgement) is implicit in the following figure.

Example of message exchange with subscription, status updates and unsubscription.

4.4.5. Command messages

A command request is sent to a specific component on a site to execute a command.

If all required arguments are present and valid, the site immediately sends a MessageAck and starts executing the command. Once the execution completes, fails or times out the site sends a CommandResponse.

If a required argument is missing or any argument is invalid the site responds with a MessageNotAck and does not send a CommandResponse.

All arguments in a CommandRequest are required unless specifically marked as optional in the SXL. See the section about Incomplete commands.

Only a single command (cCI) is allowed in a CommandRequest or CommandResponse. See the section about More than one command.

4.4.5.1. Message structure

4.4.5.1.1. Structure of a command request

A command request message has the structure according to the example below. A command request message with the intent to change a value of the requested component.

{
     "mType": "rSMsg",
     "type": "CommandRequest",
     "mId": "cf76365e-9c7b-44a4-86bd-d107cdfc3fcf",
     "ntsOId": "O+14439=481WA001",
     "xNId": "",
     "cId": "O+14439=481WA001",
     "arg": [
         {
             "cCI": "M0001",
             "n": "status",
             "cO": "setValue",
             "v": "YellowFlash"
         },{
             "cCI": "M0001",
             "n": "securityCode",
             "cO": "setValue",
             "v": "123"
         },{
             "cCI": "M0001",
             "n": "timeout",
             "cO": "setValue",
             "v": "30"
         },{
             "cCI": "M0001",
             "n": "intersection",
             "cO": "setValue",
             "v": "1"
         }
     ]
}

JSon code 20: A command request message

The command code (cCI) and name of the argument (n) are placed in an array (arg).

The following table is describing the variable content of the message:

Values to send with the command (arguments)

Table 4.19 Command argument

Element	Type	Description
arg	array	Arguments. Contains the elements cCI, n, cO, v in an array

The following table describes the variable content of the message which is defined by the SXL.

Table 4.20 Command arguments defined by SXL

Element	Type	Description
cCI	string	Command code id
n	string	Name of the argument
cO	string	Command. Optionally used for RPC (Remote Procedure Call)
v	(defined in SXL)	(defined in SXL)

4.4.5.1.2. Structure of a command response message

A command response message has the structure according to the example below. A command response message informs about the updated value of the requested component.

The command code (cCI) and name (n) are placed in an array (rvs) in order to enable support for responding to multiple commands at once.

{
     "mType": "rSMsg",
     "type": "CommandResponse",
     "mId": "0fd63726-be19-4c09-8553-48451735cb0b",
     "ntsOId": "O+14439=481WA001",
     "xNId": "",
     "cId": "O+14439=481WA001",
     "cTS": "2015-06-08T11:49:03.293Z",
     "rvs": [
          {
             "cCI": "M0001",
             "n": "status",
             "v": "YellowFlash",
             "age": "recent"
          },{
             "cCI": "M0001",
             "n": "securityCode",
             "v": "123",
             "age": "recent"
          },{
             "cCI": "M0001",
             "n": "timeout",
             "v": "30",
             "age": "recent"
          },{
             "cCI": "M0001",
             "n": "intersection",
             "v": "1",
             "age": "recent"
          }
     ]
}

JSon code 21: A command response message

The following table is describing the variable content of the message:

Table 4.21 Command response

Element	Type	Description
cTS	(timestamp)	Timestamp for the command reponse. All timestamps are set at the site (and not in the supervision system) when the event occurs (and not when the message is sent). See also the data type section.

4.4.5.1.3. Return values (returnvalue)

Return values (rvs) is always sent but can be empty if not return values are defined.

Table 4.22 Command return values

Element	Type	Description
rvs	(array)	Return values. Contains the elements cCI, v, n and q in an array.

The following table describes the variable content defined by the signal exchange list (SXL).

Table 4.23 Return values

Element	Type	Description
cCI	string	Command code id
n	string	Name of the return value
v	(defined in SXL)	(defined in SXL)

The following table describes additional variable content of the message.

Table 4.24 Command return value

Element	Value	Description
age	recent	The value is up to date
	old	The value is not up to date
	undefined	The component does not exist. v should be set to null.
	unknown	The value is unknown. v should be set to null.

4.4.5.2. Message exchange between site and supervision system/other equipment

Message acknowledgement (see section Message acknowledgement) is implicit in the following figure.

1. Command request

2. Command response

4.4.6. Message acknowledgement

Message acknowledgement is sent as an initial answer to all other messages. This type of message should not be mixed up with alarm acknowledgement, which has a different function. The purpose of message acknowledgement is to detect communication disruptions, function as an acknowledgment that the message has reached its destination and to verify that the message was understood.

There are two types of message acknowledgement – Message acknowledgment (MessageAck) which confirms that the message was understood and Message not acknowledged (MessageNotAck) which indicates that the message was not understood.

• If no message acknowledgement is received within a predefined time, then each communicating party should treat it as a communication disruption. (See Communication disruption)

• The default timeout value should be 30 seconds.

• If the version messages has not been exchanged according to communication establishment sequence (See Communication establishment between sites and supervision system and Communication establishment between sites) then message acknowledgement (MessageAck/MessageNotAck) should not be sent as a response to any other messages other than the version message (See RSMP/SXL Version). The lack of acknowledgement forces the other communicating party to treat it as communication disruption and disconnect and reconnect, ensuring that the connection restarts with communication establishment sequence.

The acknowledgement messages are interaction driven and are sent when any other type message are received.

4.4.6.1. Message structure – Message acknowledgement

An acknowledgement message has the structure according to the example below.

{
     "mType": "rSMsg",
     "type": "MessageAck",
     "oMId": "49c6c824-d593-4c16-b335-f04feda16986"
}

JSon code 22: An acknowledgement message

4.4.6.2. Message structure – Message not acknowledged

A “not acknowledgement” message has the structure according to the example below.

{
     "mType": "rSMsg",
     "type": "MessageNotAck",
     "oMId": "554dff0-9cc5-4232-97a9-018d5796e86a",
     "rea": "Unknown packet type: Watchdddog"
}

JSon code 23: A not acknowledgement message

The following table is describing the variable content of the message:

Table 4.25 Message not ack

Element	Type	Description
rea	string	(optional) Error message where all relevant information about the nature of the error can be provided.

4.4.6.3. Message exchange between site and supervision system/other equipment

Supervision system sends initial message

1. A message is sent from supervision system or other equipment

2. The site responds with an message acknowledgement

Site sends initial message

1. A message is sent from the site

2. The supervision system or other equipment responds with an message acknowledgement

4.4.7. RSMP/SXL Version

RSMP/SXL Version is the initial message when establishing communication.

It contains:

• Site Id

• SXL versions

• All supported RSMP versions

The Site Id and SXL revision must match between the communicating parties.

If there is a mismatch or if there are no RSMP version that both communicating parties support, see Communication rejection.

The version message should be implemented in such a way that it should be possible to add additional tags/variables (e.g. date) without affecting existing implementations.

The principle of the message exchange is defined by the communication establishment (See Communication establishment between sites and supervision system and Communication establishment between sites).

4.4.7.1. Message structure

A version message has the structure according to the example below. In the example below the system has support for RSMP version 3.1.1, 3.1.2 and SXL version 1.0.13 for site O+14439=481WA001.

{
     "mType": "rSMsg",
     "type": "Version",
     "mId": "6f968141-4de5-42ff-8032-45f8093762c5",
     "step": "Request"
     "RSMP": [
         {
             "vers": "3.1.1"
         },{
             "vers": "3.1.2"
         }
     ],
     "siteId": [
         {
             "sId": "O+14439=481WA001"
         }
     ],
     "SXL": "1.0.13",
     "receiveAlarms": false
}

JSon code 24: A RSMP / SXL message

The following table describes the variable content of the message which is defined by the SXL.

The Site config columns describes the correlation between the JSon elements and the titles in the site configuration.

Table 4.26 Version information defined by site configuration

Element	Type	Site config (Excel)	Site config (YAML)	Description
sId	string	SiteId		Site id
SXL	string	SXL revision	version	Revision of SXL. E.g ”1.3”

It is possible to use more than one site id in a single RSMP connection. Therefore the site ids that are used in the RSMP connection are sent in the message using an array with sId.

The following table describes additional variable content of the message.

Table 4.27 Version information

Element	Type	Description
step	string	Must be set to ‘Request’ in the initial Version message sent by the site, and to ‘Response’ in the Version message returned by the supervisor.
vers	string	Version of RSMP. E.g. ”3.1.2”, ”3.1.3” or ”3.1.4”. All the supported RSMP versions are sent in the message using an array (RSMP).
receiveAlarms	boolean	Supervisor can set this to false if they do not want to receive alarms.

The receiveAlarms attribute is optional and can only be set in the Version response sent by the supervisors, not the initial Version request sent by the site.

• If set to false, the site must not send any alarm message to the supervisor except if the supervisor requests, suspends or acknowledges an alarm.

• If set to true, or omitted, site must send alarms to the supervisor as normal.

The supervisor can request, acknowledge and suspend/resume alarms even if the receiveAlarms attribute was set to false.

4.4.8. Watchdog

The primary purpose of watchdog messages is to ensure that the communication remains established and to detect any communication disruptions between site and supervision system. For any subsystem alarms are used instead.

The secondary purpose of watchdog messages is to provide a timestamp that can be used to check time synchronization. However watchdog messages should not be used to adjust the clock. Instead more robust synchronization methods, e.g. NTP or GPS, should be used to synchronize clocks.

The interval duration for sending watchdog messages should be configurable at both the site and the supervision system. The default setting should be (1) once a minute.

Watchdog messages are sent in both directions, both from the site and from the supervision system. At initial communication establishment (after version message) the watchdog message should be sent.

4.4.8.1. Message structure

A watchdog message has the structure according to the example below.

{
     "mType": "rSMsg",
     "type": "Watchdog",
     "mId": "f48900bc-e6fb-431a-8ca4-05070016f64a",
     "wTs": "2015-06-08T12:01:39.654Z"
}

JSon code 25: A watchdog message

The following table is describing the variable content of the message:

Table 4.28 Watchdog

Element	Type	Description
wTs	(timestamp)	Timestamp for the watchdog. See also the data type section.

4.4.8.2. Message exchange between site and supervision system/other equipment

Message acknowledgement (see section Message acknowledgement) is implicit in the following figures.

Site sends watchdog message

1. Watchdog message is sent from site

Supervision system/other equipment sends watchdog message

1. Watchdog message is sent from supervision system/other equipment