4 Messaging

Prepare a SIF_Message/SIF_Provision message with SIF_Header containing a new GUID in SIF_MsgId, your Agent's Agent Id in SIF_SourceId and the current time in SIF_Timestamp; other SIF_Header elements do not apply.

Include SIF_ProvideObjects and for each object your Agent would like to provide, place a SIF_Object element with an ObjectName and optionally one or more SIF_Context names (which default to SIF_Default if omitted). Your Agent can also state its support for SIF_ExtendedQuery in SIF_ExtendedQuerySupport, which defaults to false.

Include SIF_SubscribeObjects and for each object to which your Agent would like to subscribe, place a SIF_Object element with an ObjectName and optionally one or more SIF_Context names (which default to SIF_Default if omitted).

Include SIF_PublishAddObjects, SIF_PublishChangeObjects and SIF_PublishDeleteObjects elements and include a SIF_Object element with an ObjectName in the respective sections for each event type your agent publishes with regard to that object. Optionally specify for each object one or more SIF_Context names (which default to SIF_Default if omitted).

Include SIF_RequestObjects and for each object your Agent requests, place a SIF_Object element with an ObjectName and optionally one or more SIF_Context names (which default to SIF_Default if omitted). Your Agent can also state its support for SIF_ExtendedQuery in SIF_ExtendedQuerySupport, which defaults to false.

Include SIF_RespondObjects and for each object for which your Agent processes requests (including those listed in SIF_ProvideObjects), include a SIF_Object element with an ObjectName and optionally one or more SIF_Context names (which default to SIF_Default if omitted). Your Agent can also state its support for SIF_ExtendedQuery in SIF_ExtendedQuerySupport, which defaults to false.

Prepare a SIF_Message/SIF_Event message with SIF_Header containing a new GUID in SIF_MsgId, your Agent's Agent Id in SIF_SourceId and the current time in SIF_Timestamp. If your Agent would like to indicate minimum encryption and/or authentication requirements for Agents receiving this SIF_Event; supply SIF_Security with the appropriate settings; use an equally secure channel when communicating with the ZIS, if desired. If this event specifically applies to one or more contexts, place them in SIF_Contexts; if omitted, the context is SIF_Default.

Specify the name of the object that is being added, changed or deleted in SIF_EventObject/@ObjectName. Place the type of event in SIF_EventObject/@Action and place the object in SIF_EventObject. For an Add event, this MUST be the complete object with all mandatory elements present. If the agent wishes to indicate that a particular optional element is supported but has no value, the element MAY be included as empty, with xsi:nil set to true if necessary.

For a Change event, all unchanged elements, whether mandatory or optional SHOULD be omitted from the object. Optional elements that have been deleted MAY be included as empty, with xsi:nil set to true if necessary. For each list of repeatable elements in the object that has changed, include the whole list if the list type indicated is List. If the list type is ActionList, the agent MAY include only those elements in the list that have been added, changed or deleted. If an element has been deleted from an ActionList, the element MUST be included with at least its key attribute(s) and/or element(s) specified, and include a SIF_Action attribute value of Delete on the deleted child element in the list. Omitting an element in an ActionList indicates that it has been unchanged in the event. Refer to the Data Model section of the specification, Lists/Repeatable Elements, for more details on ActionLists and Lists.

For a Delete event, only elements/attributes that identify the object sufficiently for deletion SHOULD be included. This set of identifying elements/attributes are typically communicated by the mandatory root attributes of an object, which MUST be included.

Prepare a SIF_Message/SIF_Request message with SIF_Header containing a new GUID in SIF_MsgId, your Agent's Agent Id in SIF_SourceId and the current time in SIF_Timestamp. If your Agent would like to indicate minimum encryption and/or authentication requirements for Agents receiving this SIF_Request, supply SIF_Security with the appropriate settings; use an equally secure channel when communicating with the ZIS, if desired. If this request is associated with a context, specify a single SIF_Context in SIF_Contexts; if omitted, the context is SIF_Default. If your Agent would like to explicitly route this request to a given Agent, specify the Agent's Id in SIF_DestinationId. Specify the SIF versions the responder may choose from when returning data in SIF_Version. Each version specified MUST be registered at the ZIS as supported by your Agent. Specify the maximum buffer size the Responder must respect when sending SIF_Response packets; this MUST be less than or equal to the SIF_MaxBufferSize with which your Agent registered with the ZIS.

If using SIF_ExtendedQuery, go to step 3; otherwise go to step 2.

If your Agent did not invoke or end SMB for a SIF_Event, the referenced message has been removed from your Agent's queue, unless your agent indicated a transport error or that it was sleeping (in which case the message has been acknowledged but remains in your Agent's queue).

If your Agent invoked SMB by sending an intermediate SIF_Ack, delivery of events is blocked until your Agent removes the SIF_Event from its queue by sending a final SIF_Ack. Your Agent will continue to receive SIF_Responses and SIF_Requests.

If your Agent ended SMB by sending a final SIF_Ack, the ZIS has removed the blocked event from your Agent's queue and resumes delivery of events to your Agent.

Initialize Current Packet Number to 1.

Initialize ServiceMsgId to a new GUID. The SIF_ServiceMsgId MUST be the same for all packets.

Prepare a new SIF_ServiceNotify message.

Initialize the SIF_Header containing a new GUID in SIF_MsgId, your Agent's Agent Id in SIF_SourceId and the current time in SIF_Timestamp.

If the agent would like to indicate minimum encryption and/or authentication requirements for agents receiving this SIF_ServiceNotify, supply SIF_Security with the appropriate settings. Use an equally secure channel when communicating with the Zone, if desired.

If this SIF_ServiceNotify specifically applies to one or more contexts, place them in SIF_Contexts; if omitted, the context is SIF_Default.

Set SIF_PacketNumber to the Current Packet Number.

Set SIF_Service to the name of the SIF Zone Service.

Set SIF_Operation to the name of the operation.

Set SIF_ServiceMsgId to the ServiceMsgId created in Step 1.

Initialize SIF Zone Service operation SIF_Body and set the appropriate values for the operation call.

If the operation SIF_Body supports packets, add records to the SIF_Body while the SIF_Message + SIF_Body is less than either the default SIF Zone Service buffer size or the stated buffer size within the SIF Zone Service documentation. If a record cannot be added under the maximum buffer size abort processing the operation.

Add the SIF_Body to the SIF_ServiceNotify.

• Set SIF_MorePackets to No.
• Create a new SIF_Error with the SIF_Error/SIF_Code and SIF_Error/SIF_Desc set to "Responder does not support requested SIF_MaxBufferSize."
• Send the SIF_ServiceNotify to the Zone. If the first SIF_ServiceNotify packet was not sent, the agent may not have to send the error to the Zone. It may abort the SIF_ServiceNotify.
• The agent should log the error.

Initialize Current Packet Number to 1

Initialize ServiceMsgId to a new GUID. The SIF_ServiceMsgId MUST be the same for all packets.

Prepare a new SIF_ServiceInput message.

Initialize the SIF_Header containing a new GUID in SIF_MsgId, your Agent's Agent Id in SIF_SourceId and the current time in SIF_Timestamp.

If your Agent would like to explicitly route this service operation to a given Agent, specify the Agent's Id in SIF_DestinationId.

If the agent would like to indicate minimum encryption and/or authentication requirements for agents receiving this SIF_ServiceNotify, supply SIF_Security with the appropriate settings. Use an equally secure channel when communicating with the Zone, if desired.

Since a SIF_ServiceInput applies only to the default context, it is not necessary to specify a value for SIF_Contexts.

Set SIF_PacketNumber to the Current Packet Number.

Set SIF_Service to the name of the SIF Zone Service.

Set SIF_Operation to the name of the operation.

Set SIF_ServiceMsgId to the ServiceMsgId created in Step 1.

Specify the SIF versions the responder may choose from when returning data in SIF_Version. Each version specified MUST be registered in the ZIS as supported by your Agent. It is RECOMMENDED to use 2.*.

Specify the maximum buffer size the Responder must respect when sending SIF_ServiceOutput packets; this MUST be less than or equal to the SIF_MaxBufferSize with which your Agent registered with the Zone.

Initialize SIF Zone Service operation SIF_Body and set the appropriate values for the operation call.

If the operation SIF_Body supports packets, add records to the SIF_Body while the SIF_Message + SIF_Body is less than either the default SIF Zone Service buffer size or the stated buffer size within the SIF Zone Service documentation. If a record cannot be added under the maximum buffer size, abort processing the operation.

Add the SIF_Body to the SIF_ServiceInput.

• Set SIF_MorePackets to No.
• Create a new SIF_Error with the SIF_Error/SIF_Code and SIF_Error/SIF_Desc set to "Responder does not support requested SIF_MaxBufferSize."
• Send the SIF_ServiceNotify to the Zone. If the first SIF_ServiceInput packet was not sent, the agent may not have to send the error to the Zone. It may abort the SIF_ServiceInput.
• The agent should log the error.

Prepare a SIF_Ack message with SIF_Header containing a new GUID in SIF_MsgId, your Agent's Agent Id in SIF_SourceId and the current time in SIF_Timestamp; other SIF_Header elements do not apply. Place the incoming SIF_Header/SIF_SourceId and SIF_Header/SIF_MsgId in SIF_OriginalSourceId and SIF_OriginalMsgId, respectively. Place 2 (intermediate SIF_Ack) in SIF_Status/SIF_Code.

If your Agent is a Push-Mode Agent, return the SIF_Ack to the ZIS and commence sending the necessary requests as described in the SIF_Request protocol above to complete processing of the event per your Agent's business rules. When complete or if an error occurs, end SMB as described in the SIF_Ack (Push-Mode) protocol above.

If your Agent is a Pull-Mode Agent, send the SIF_Ack to the ZIS per SIF_Ack (Pull-Mode) above and commence sending the necessary requests as described in the SIF_Request protocol above to complete processing of the event per your Agent's business rules. When complete or if an error occurs, end SMB as described in the SIF_Ack (Pull-Mode) protocol above.

If an error occurs, it is RECOMMENDED that your Agent publish a SIF_LogEntry Add event.

If your Agent is a Pull-Mode Agent, process the event per your Agent's business rules. When complete or if an error occurs, acknowledge the message and remove it from your Agent's queue per SIF_Ack (Pull-Mode) above.

If your Agent is a Push-Mode Agent, it has one of two options: process the event, then acknowledge it; or acknowledge the event, then process it. The advantage of first processing the event is the ability to return a descriptive error, if necessary, to the ZIS when acknowledging the message. The disadvantage of first processing is that if the processing is long running, the connection from the ZIS to your Agent may time out, which will lead to the event being redelivered to your Agent in another delivery attempt, to possibly run into another time-out. To avoid the latter, it is RECOMMENDED that your Push-Mode Agent first acknowledge the event, then process it, unless event processing is known to always occur within a reasonable amount of time. Agents that first acknowledge then process SHOULD persist the event locally until processing is complete, as the event is removed from your Agent's queue upon successful acknowledgement, otherwise the event will be lost in the case of an application or system error that affects your Agent's ability to complete processing of the event.

Choose an option and process the event according to your Agent's business rules. When acknowledging: Prepare a SIF_Ack message with SIF_Header containing a new GUID in SIF_MsgId, your Agent's Agent Id in SIF_SourceId and the current time in SIF_Timestamp; other SIF_Header elements do not apply. Place the incoming SIF_Header/SIF_SourceId and SIF_Header/SIF_MsgId in SIF_OriginalSourceId and SIF_OriginalMsgId, respectively. Place 1 (immediate SIF_Ack) in SIF_Status/SIF_Data in the case of successful processing, and return the SIF_Ack to the ZIS. If an error has occurred, include a SIF_Error element with an appropriate SIF_Category and SIF_Code and describe the error as needed in SIF_Desc and optionally SIF_ExtendedDesc. Note that indicating a transport error will not remove the message from your Agent's queue, only acknowledge it. The same action can be accomplished indicating 8 (receiver is sleeping) in SIF_Status/SIF_Code.

If an error occurs regardless of the option chosen, it is RECOMMENDED that your Agent publish a SIF_LogEntry Add event.

Prepare a SIF_Response message with a copy of SIF_Contexts, SIF_DestinationId set to SIF_SourceId and SIF_RequestMsgId set to SIF_MsgId from the SIF_Request message.

Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate General Message Handling and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate that the requested context is not supported.

Add SIF_PacketNumber with a value of 1 and set SIF_MorePackets to No.

Send the SIF_Response to the original requester and acknowledge the error to the ZIS.

Prepare a SIF_Response message with a copy of SIF_Contexts, SIF_DestinationId set to SIF_SourceId and SIF_RequestMsgId set to SIF_MsgId from the SIF_Request message.

Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate Request and Response and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate that the requested SIF_Versions are not supported.

Add SIF_PacketNumber with a value of 1 and set SIF_MorePackets to No.

Send the SIF_Response to the original requester and acknowledge the error to the ZIS.

Using the SIF version selected in Step 1, prepare a SIF_Response message with SIF_DestinationId set to SIF_SourceId and SIF_RequestMsgId set to SIF_MsgId from the SIF_Request message.

Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate Request and Response and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate that the SIF_MaxBufferSize cannot be honored.

Add SIF_PacketNumber with a value of 1 and set SIF_MorePackets to No.

Send the SIF_Response to the original requester and acknowledge the error to the ZIS.

Prepare a SIF_Response message using the version chosen in Step 1 with SIF_DestinationId set to SIF_SourceId and SIF_RequestMsgId set to SIF_MsgId from the SIF_Request message.

Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate Request and Response and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate that the object is not supported.

Add SIF_PacketNumber with a value of 1 and set SIF_MorePackets to No.

Send the SIF_Response to the original requester and acknowledge the error to the ZIS.

Prepare a SIF_Response message with SIF_DestinationId set to SIF_SourceId and SIF_RequestMsgId set to SIF_MsgId from the SIF_Request message.

Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate Request and Response and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate that the query is not supported.

Add SIF_PacketNumber with a value of 1 and set SIF_MorePackets to No.

Send the SIF_Response to the original requester and acknowledge the error to the ZIS.

Prepare a SIF_Response message with SIF_DestinationId set to SIF_SourceId and SIF_RequestMsgId set to SIF_MsgId from the SIF_Request message.

Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate Request and Response and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate that the query is not supported.

Add SIF_PacketNumber with a value of 1 and set SIF_MorePackets to No.

Send the SIF_Response to the original requester and acknowledge the error to the ZIS.

Note that Push-Mode Agents should acknowledge receipt of the SIF_Request as response generation is typically a long-running operation that will typically lead to HTTP time-outs. As the request will be removed from the Agent's queue, it is RECOMMENDED that the Push-Mode Agent persist the request and its SIF_PacketNumber while generating responses, in case of an application or system failure that prevents it from completing the request processing; upon restarting, the Agent can end the response stream with a SIF_Error, SIF_PacketNumber set to the last successfully transmitted SIF_PacketNumber + 1 and SIF_MorePackets set to No.

If a Push-Mode Agent elects to successfully acknowledge the request before processing, it can do so. Otherwise it should acknowledge receipt of the request upon completion of response generation.

Pull-Mode Agents can choose to acknowledge receipt of the request here or at the end of response generation.

Initialize packet counter to 1.

The Responder's handling of your Agent's SIF_Request has failed due to a SIF_Error condition. See Error Codes with SIF_Category and SIF_Code, and examine SIF_Desc and SIF_ExtendedDesc, if included. This is the last packet your Agent will receive associated with that request.

If your Agent is a Pull-Mode Agent, acknowledge the message per SIF_Ack (Pull-Mode) above.

If your Agent is a Push-Mode Agent: Prepare a SIF_Ack message with SIF_Header containing a new GUID in SIF_MsgId, your Agent's Agent Id in SIF_SourceId and the current time in SIF_Timestamp; other SIF_Header elements do not apply. Place the incoming SIF_Header/SIF_SourceId and SIF_Header/SIF_MsgId in SIF_OriginalSourceId and SIF_OriginalMsgId, respectively. Place 1 (immediate SIF_Ack) in SIF_Status/SIF_Data, and return the SIF_Ack to the ZIS.

If your Agent is a Pull-Mode Agent, process the response per your Agent's business rules. When complete or if an error occurs, acknowledge the message and remove it from your Agent's queue per SIF_Ack (Pull-Mode) above.

If your Agent is a Push-Mode Agent, it has one of two options: process the response, then acknowledge it; or acknowledge the response, then process it. The advantage of first processing the response is the ability to return a descriptive error, if necessary, to the ZIS when acknowledging the message. The disadvantage of first processing is that if the processing is long running, the connection from the ZIS to your Agent may time out, which will lead to the response being redelivered to your Agent in another delivery attempt, to possibly run into another time-out. To avoid the latter, it is RECOMMENDED that your Push-Mode Agent first acknowledge the response, then process it, unless response processing is known to always occur within a reasonable amount of time. Agents that first acknowledge then process SHOULD persist the response locally until processing is complete, as the response is removed from your Agent's queue upon successful acknowledgement, otherwise the response will be lost in the case of an application or system error that affects your Agent's ability to complete processing of the response.

Choose an option and process the response according to your Agent's business rules. When acknowledging: Prepare a SIF_Ack message with SIF_Header containing a new GUID in SIF_MsgId, your Agent's Agent Id in SIF_SourceId and the current time in SIF_Timestamp; other SIF_Header elements do not apply. Place the incoming SIF_Header/SIF_SourceId and SIF_Header/SIF_MsgId in SIF_OriginalSourceId and SIF_OriginalMsgId, respectively. Place 1 (immediate SIF_Ack) in SIF_Status/SIF_Data in the case of successful processing, and return the SIF_Ack to the ZIS. If an error has occurred, include a SIF_Error element with an appropriate SIF_Category and SIF_Code and describe the error as needed in SIF_Desc and optionally SIF_ExtendedDesc. Note that indicating a transport error will not remove the message from your Agent's queue, only acknowledge it. The same action can be accomplished indicating 8 (receiver is sleeping) in SIF_Status/SIF_Code.

If an error occurs regardless of the option chosen, it is RECOMMENDED that your Agent publish a SIF_LogEntry Add event.

If your Agent is a Pull-Mode Agent, process the service event per your Agent's business rules. When complete or if an error occurs, acknowledge the message and remove it from your Agent's queue per SIF_Ack (Pull-Mode) above.

If your Agent is a Push-Mode Agent, it has one of two options: process the service event, then acknowledge it; or acknowledge the service event, then process it. The advantage of first processing the event is the ability to return a descriptive error, if necessary, to the ZIS when acknowledging the message. The disadvantage of first processing is that if the processing is long running, the connection from the ZIS to your Agent may time out, which will lead to the event being redelivered to your Agent in another delivery attempt, to possibly run into another time-out. To avoid the latter, it is RECOMMENDED that your Push-Mode Agent first acknowledge the event, then process it, unless event processing is known to always occur within a reasonable amount of time. Agents that first acknowledge then process SHOULD persist the event locally until processing is complete, as the event is removed from your Agent's queue upon successful acknowledgement, otherwise the event will be lost in the case of an application or system error that affects your Agent's ability to complete processing of the service event.

Choose an option and process the service event according to your Agent's business rules. When acknowledging: Prepare a SIF_Ack message with SIF_Header containing a new GUID in SIF_MsgId, your Agent's Agent Id in SIF_SourceId and the current time in SIF_Timestamp; other SIF_Header elements do not apply. Place the incoming SIF_Header/SIF_SourceId and SIF_Header/SIF_MsgId in SIF_OriginalSourceId and SIF_OriginalMsgId, respectively. Place 1 (immediate SIF_Ack) in SIF_Status/SIF_Data in the case of successful processing, and return the SIF_Ack to the ZIS.

If an error has occurred, include a SIF_Error element with an appropriate SIF_Category and SIF_Code and describe the error as needed in SIF_Desc and optionally SIF_ExtendedDesc. Note that indicating a transport error will not remove the message from your Agent's queue, only acknowledge it. The same action can be accomplished indicating 8 (receiver is sleeping) in SIF_Status/SIF_Code.

If an error occurs regardless of the option chosen, it is RECOMMENDED that your Agent publish a SIF_LogEntry Add event.

Message handling complete.

Since a SIF_ServiceInput can apply only to the default context, it is not necessary to specify a value for SIF_Header/SIF_Contexts.

Specify the maximum buffer size the Zone Service must respect when sending SIF_ServiceOutput packets; this MUST be less than or equal to the SIF_MaxBufferSize with which your Agent registered with the ZIS.

Examine the SIF_Version element or elements specified in the SIF_ServiceInput message. If more than one version is supported, select the highest version number supported. If a wildcard * anywhere in a version was specified, choose the maximum matching version supported by your agent or the version appropriate for the Service operation.

Go to step 5 if the version is supported.

Prepare a SIF_ServiceOutput message with SIF_DestinationId set to SIF_SourceId and SIF_ServiceMsgId set to SIF_ServiceMsgId from the SIF_ServiceInput message. Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate registration and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate that the version is not supported. Add SIF_PacketNumber with a value of 1 and set SIF_MorePackets to No. Send the SIF_ServiceOutput to the Zone and acknowledge the error to the Zone via a SIF_Ack if a SIF_Ack has not already been returned.

Stop processing the message

Examine the SIF_MaxBufferSize specified in the SIF_ServiceInput message if it is greater than the minimum buffer size supported by your agent.

Go to step 7 if the buffer size is greater than the minimum buffer size in your agent.

Prepare a SIF_ServiceOutput message with SIF_DestinationId set to SIF_SourceId and SIF_ServiceMsgId set to SIF_ServiceMsgId from the SIF_ServiceInput message. Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate Zone Services and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate that the SIF_MaxBufferSize is not supported. Add SIF_PacketNumber with a value of 1 and set SIF_MorePackets to No. Send the SIF_ServiceOutput to the Zone and acknowledge the error to the Zone via a SIF_Ack if a SIF_Ack has not already been returned.

Stop processing the message

Examine the SIF_ServiceInput/SIF_Service and SIF_ServiceInput/SIF_Operation if they are supported.

Prepare a SIF_ServiceOutput message with SIF_DestinationId set to SIF_SourceId and SIF_ServiceMsgId set to SIF_ServiceMsgId from the SIF_ServiceInput message. Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate Zone Services and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate that the SIF_Service and/or SIF_Operation is invalid. Add SIF_PacketNumber with a value of 1 and set SIF_MorePackets to No. Send the SIF_ServiceOutput to the Zone and acknowledge the error to the Zone via a SIF_Ack if a SIF_Ack has not already been returned.

Stop processing the message

Process the service operation accordingly.

Prepare a SIF_ServiceOutput message with SIF_DestinationId set to SIF_SourceId and SIF_ServiceMsgId set to SIF_ServiceMsgId from the SIF_ServiceInput message. Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate Zone Services and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate that the SIF_Service and/or SIF_Operation failed. Add SIF_PacketNumber with a value of 1 and set SIF_MorePackets to No. Send the SIF_ServiceOutput to the Zone and acknowledge the error to the Zone via a SIF_Ack if a SIF_Ack has not already been returned.

Stop processing the message

Initialize Current Packet Number to 1
Collect sender's SIF_SourceId from SIF_ServiceInput/SIF_Header/SIF_SourceId
Collect Maximum Buffer Size from SIF_ServiceInput/SIF_MaxBufferSize
Collect SIF_Version(s) from SIF_ServiceInput/SIF_Version

The Responder's handling of your Agent's SIF_ServiceIn has failed due to a SIF_Error condition. See Error Codes with SIF_Category and SIF_Code, and examine SIF_Desc and SIF_ExtendedDesc, if included. This is the last packet your Agent will receive associated with that request.

If your Agent is a Pull-Mode Agent, acknowledge the message per SIF_Ack (Pull-Mode) above.

If your Agent is a Push-Mode Agent: Prepare a SIF_Ack message with SIF_Header containing a new GUID in SIF_MsgId, your Agent's Agent Id in SIF_SourceId and the current time in SIF_Timestamp; other SIF_Header elements do not apply. Place the incoming SIF_Header/SIF_SourceId and SIF_Header/SIF_MsgId in SIF_OriginalSourceId and SIF_OriginalMsgId, respectively. Place 1 (immediate SIF_Ack) in SIF_Status/SIF_Data, and return the SIF_Ack to the ZIS.

If your Agent is a Pull-Mode Agent, process the response per your Agent's business rules. When complete or if an error occurs, acknowledge the message and remove it from your Agent's queue per SIF_Ack (Pull-Mode) above.

If your Agent is a Push-Mode Agent, it has one of two options: process the response, then acknowledge it; or acknowledge the response, then process it. The advantage of first processing the response is the ability to return a descriptive error, if necessary, to the ZIS when acknowledging the message. The disadvantage of first processing is that if the processing is long running, the connection from the ZIS to your Agent may time out, which will lead to the response being redelivered to your Agent in another delivery attempt, to possibly run into another time-out. To avoid the latter, it is RECOMMENDED that your Push-Mode Agent first acknowledge the response, then process it, unless response processing is known to always occur within a reasonable amount of time. Agents that first acknowledge then process SHOULD persist the response locally until processing is complete, as the response is removed from your Agent's queue upon successful acknowledgement, otherwise the response will be lost in the case of an application or system error that affects your Agent's ability to complete processing of the response.

Choose an option and process the response according to your Agent's business rules. When acknowledging: Prepare a SIF_Ack message with SIF_Header containing a new GUID in SIF_MsgId, your Agent's Agent Id in SIF_SourceId and the current time in SIF_Timestamp; other SIF_Header elements do not apply. Place the incoming SIF_Header/SIF_SourceId and SIF_Header/SIF_MsgId in SIF_OriginalSourceId and SIF_OriginalMsgId, respectively. Place 1 (immediate SIF_Ack) in SIF_Status/SIF_Data in the case of successful processing, and return the SIF_Ack to the ZIS. If an error has occurred, include a SIF_Error element with an appropriate SIF_Category and SIF_Code and describe the error as needed in SIF_Desc and optionally SIF_ExtendedDesc. Note that indicating a transport error will not remove the message from your Agent's queue, only acknowledge it. The same action can be accomplished indicating 8 (receiver is sleeping) in SIF_Status/SIF_Code.

If an error occurs regardless of the option chosen, it is RECOMMENDED that your Agent publish a SIF_LogEntry Add event.

Prepare a SIF_Response message with SIF_DestinationId set to SIF_SourceId and SIF_RequestMsgId set to SIF_MsgId from the SIF_Request message.

Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate Request and Response and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate the reason that the SIF_Response packet was rejected.

Add SIF_PacketNumber with a value set to set to 1 + the previous SIF_PacketNumber and SIF_MorePackets to No.

Send the SIF_Response to the original requester. In addition, the ZIS MUST report a SIF_LogEntry event with the appropriate error category and code, containing a copy of the SIF_Header from the request. SIF_LogEntry/SIF_ExtendedDesc should contain information about why the message failed SIF_Response validation.

Stop processing the message.

The ZIS must also guarantee that no additional SIF_Response packets for this SIF_Request will be accepted. Depending on the implementation, the ZIS may need to alter the SIF_Request cache it maintains to signal that the SIF_Request is no longer valid.

The ZIS may remove the SIF_Request from the cache as the stream is closed.

Add a SIF_Error element with the SIF_Category set to indicate Request and Response, with SIF_Code and SIF_Desc indicating 18 (SIF_Request cancelled by requesting agent).

Add SIF_PacketNumber with a value set to the previous SIF_PacketNumber + 1. Set SIF_MorePackets to No.

Place the SIF_Response in the requester's queue.

Add a SIF_Error element with the SIF_Category set to indicate SIF Zone Service, with SIF_Code and SIF_Desc indicating 15 (SIF_ServiceInput cancelled by requesting agent).

Add SIF_PacketNumber with a value set to the previous SIF_PacketNumber + 1. Set SIF_MorePackets to No.

Place the SIF_ServiceOutput in the requester's queue.

The Agent has violated protocol. End SMB if it has been invoked by the Agent and remove the blocked SIF_Event from the Agent's queue. Indicate SIF_Error/SIF_Category of 13 (SMB Error) and SIF_Error/SIF_Code  3 (final SIF_Ack expected).

It is RECOMMENDED that your ZIS log the error. Your ZIS MAY post a SIF_LogEntry  Add event with the same error category and code above, containing a copy of the SIF_Header of the message.

The Agent has violated protocol. As there can be only one event blocked by SMB, end SMB for the agent and remove the blocked SIF_Event from the Agent's queue, if any. Indicate SIF_Error/SIF_Category of 13 (SMB Error) and SIF_Error/SIF_Code  4 (incorrect SIF_MsgId in final SIF_Ack).

It is RECOMMENDED that your ZIS log the error. Your ZIS MAY post a SIF_LogEntry  Add event with the same error category and code above, containing a copy of the SIF_Header of the message.

The Agent has violated protocol. Indicate SIF_Error/SIF_Category of 12 (Generic Message Handling Error) and SIF_Error/SIF_Code 5 (protocol error) for the message.

Using the SIF_SourceId, consult the ACL to determine if the sender has the proper access and permissions for this service and operation in the specified context.

If sender has the proper access and permissions, go to step 3.

Prepare a SIF_Ack containing a SIF_Error element. Set SIF_Error/SIF_Category to indicate SIF Zone Service. Set SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate ACL permission denied. Return the SIF_Ack to the caller.

Stop processing message.

Using the SIF_SourceId, consult the SIF_ZoneStatus to determine if the sender is a service provider.

If sender is a service provider go to step 5

Prepare a SIF_Ack containing a SIF_Error element. Set SIF_Error/SIF_Category to indicate Access and Permission Error. Set SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate the Agent has no permission to provide the service. Return the SIF_Ack to the caller.

Stop processing message.

If the SIF_PacketNumber is correct go to step 7

Prepare a SIF_Ack containing a SIF_Error element. Set SIF_Error/SIF_Category to indicate SIF Zone Service. Set SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate the SIF_PacketNumber is incorrect. Place a description of the SIF_PacketNumber specified and the SIF_PacketNumber expected in SIF_Error/SIF_ExtendedDesc. Return the SIF_Ack to the caller.

If the packet stream has not been terminated by the ZIS go to step 10.

Check the Subscriber database to see if there are any subscribers in the specified contexts for the specific SIF_Service and SIF_Operation from the SIF_ServiceNotify. The identification of a subscriber is based upon the service name and operation name.

Go to Step 9 if there are no subscribers for this notification event.

Place a copy of the SIF_ServiceNotify message into each subscribing agent's queue. If more than one context is specified for the event, only one copy of the event is placed in the subscribing agent's queue. If the SIF_ServiceNotify cannot be placed into an individual agent's queue due to the agent's maximum buffer size or because the subscribing agent does not support the message version of the SIF_ServiceNotify, it is RECOMMENDED that the ZIS log the inability to deliver the event. In addition, the ZIS MUST report a SIF_LogEntry event with the appropriate error category and code, containing a copy of the SIF_Header from the original message. SIF_LogEntry/SIF_Desc must contain the SourceId of the agent that has failed to receive the message.

Prepare a SIF_Ack containing a SIF_Status element indicating success. Return a SIF_Ack to the caller.

Stop processing the message.

Prepare a SIF_ServiceNotify message with a copy of the information in the original SIF_ServiceNotify except for the SIF_Body.

Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate SIF Zone Service and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate the reason that the SIF_ServiceNotify packet was rejected.

Add SIF_PacketNumber with a value set to set to 1 + the previous SIF_PacketNumber and SIF_MorePackets to No.

Send the SIF_ServiceNotify to the subscribers. In addition, the ZIS MUST report a SIF_LogEntry event with the appropriate error category and code, containing a copy of the SIF_Header from the request. SIF_LogEntry/SIF_ExtendedDesc should contain information about why the message failed SIF_ServiceNotify validation.

Stop processing the message.

The ZIS must also guarantee that no additional SIF_ServiceNotify packets for this SIF_ServiceMsgId will be accepted. Depending on the implementation, the ZIS may need to alter the SIF_ServiceNotify cache it maintains to signal that the SIF_ServiceNotify/SIF_ServiceMsgId is no longer valid.

The ZIS may remove the SIF_ServiceNotify/SIF_ServiceMsgId from the cache as the stream is closed.

Using the SIF_SourceId, consult the ACL to determine if the sender has the proper access and permissions for this service and operation in the specified context.

If sender has the proper access and permissions, go to step 3.

Prepare a SIF_Ack containing a SIF_Error element. Set SIF_Error/SIF_Category to indicate SIF Zone Service. Set SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate ACL permission denied. Return the SIF_Ack to the caller.

Stop processing message.

If the SIF_PacketNumber is correct go to step 5

Prepare a SIF_Ack containing a SIF_Error element. Set SIF_Error/SIF_Category to indicate SIF Zone Service. Set SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate the SIF_PacketNumber is invalid. Place a description of the SIF_PacketNumber specified and the SIF_PacketNumber expected in SIF_Error/SIF_ExtendedDesc. Return the SIF_Ack to the caller.

If the packet stream has not been terminated by the ZIS go to step 13.

Examine the SIF_ServiceInput header looking for a SIF_Version.

If the SIF_ServiceOutput does not match any SIF_Version from SIF_ServiceInput: Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate SIF Zone Service and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate that a version mismatch occurred. Return the SIF_Ack to the caller

Go to Step 9 if a version match was made.

If a version match is not made, complete the step then stop processing the message.

Prepare a SIF_Ack containing a SIF_Status element indicating success. Return a SIF_Ack to the caller.

Stop processing the message.

Prepare a SIF_ServiceInput message with a copy of the information in the original SIF_ServiceInput except for the SIF_Body.

Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate SIF Zone Service and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate the reason that the SIF_ServiceInput packet was rejected.

Add SIF_PacketNumber with a value set to set to 1 + the previous SIF_PacketNumber and SIF_MorePackets to No.

Send the SIF_ServiceInput to the target agent. In addition, the ZIS MUST report a SIF_LogEntry event with the appropriate error category and code, containing a copy of the SIF_Header from the request. SIF_LogEntry/SIF_ExtendedDesc should contain information about why the message failed SIF_ServiceInput validation.

Stop processing the message.

The ZIS must also guarantee that no additional SIF_ServiceInput packets for this SIF_ServiceMsgId will be accepted. Depending on the implementation, the ZIS may need to alter the SIF_ServiceInput cache it maintains to signal that the SIF_ServiceInput/SIF_ServiceMsgId is no longer valid.

The ZIS may remove the SIF_ServiceInput/SIF_ServiceMsgId from the cache as the stream is closed.

Using the SIF_SourceId, consult the ACL to determine if the sender has the proper access and permissions for this service and operation in the specified context.

If sender has the proper access and permissions, go to step 3.

Prepare a SIF_Ack containing a SIF_Error element. Set SIF_Error/SIF_Category to indicate SIF Zone Service. Set SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate ACL permission denied. Return the SIF_Ack to the caller.

Stop processing message.

If the validation is correct go to step 5

Prepare a SIF_Ack containing a SIF_Error element. Set SIF_Error/SIF_Category to indicate SIF Zone Service. Set SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate "Packet number invalid, Buffer size exceeded."

If the packet stream has not been terminated by the ZIS go to step 9.

Prepare a SIF_Ack containing a SIF_Status element indicating success. Return a SIF_Ack to the caller.

Stop processing the message.

Prepare a SIF_ServiceOutput message with a copy of the information in the original SIF_ServiceOutput except for the SIF_Body.

Add a SIF_Error element with the SIF_Error/SIF_Category set to indicate SIF Zone Service and SIF_Error/SIF_Code and SIF_Error/SIF_Desc to indicate the reason that the SIF_ServiceOutput packet was rejected.

Add SIF_PacketNumber with a value set to set to 1 + the previous SIF_PacketNumber and SIF_MorePackets to No.

Send the SIF_ServiceOutput to the requesting agent. In addition, the ZIS MUST report a SIF_LogEntry event with the appropriate error category and code, containing a copy of the SIF_Header from the request. SIF_LogEntry/SIF_ExtendedDesc should contain information about why the message failed SIF_ServiceOutput validation.

Stop processing the message.

The ZIS must also guarantee that no additional SIF_ServiceOutput packets for this SIF_ServiceMsgId will be accepted. Depending on the implementation, the ZIS may need to alter the SIF_ServiceOutput cache it maintains to signal that the SIF_ServiceOutput/SIF_ServiceMsgId is no longer valid.

The ZIS may remove the SIF_ServiceOutput/SIF_ServiceMsgId from the cache as the stream is closed.