Content for TS 23.542 Word version: 18.4.0
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8.7 Service Switch
8.7.1 General
8.7.2 Procedure
8.7.2.1 Service switch in a PIN with PIN server support
8.7.2.1.1 General
8.7.2.1.2 PIN Service Switch procedure
8.7.2.1.3 PIN Service Switch Configure procedure
8.7.2.1.4 PIN Service Switch subscription
8.7.2.1.4.1 General
8.7.2.1.4.2 Procedure
8.7.2.1.4.2.1 PIN service switch subscribe
8.7.2.1.4.2.2 PIN service switch notify
8.7.2.1.4.2.3 PIN service switch update
8.7.2.1.4.2.4 PIN service switch unsubscribe
8.7.2.2 Service switch in a PIN without PIN server support
8.7.3 Information flows
8.7.4 APIs
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8.7 Service Switch p. 91
8.7.1 General p. 91
PIN service switch procedures enable a PIN Element participating in a PIN to transfer application session(s) to a different PIN Element participating in the same PIN. For example, a first PIN Element (e.g. a UE) can transfer a video streaming session to a second PIN Element (e.g. a television). PIN service switch can be triggered by a PIN Element when needed, for example when the first PIN Element joins a PIN and determines that an application flow can be switched to a second PIN Element present in that PIN.
Two scenarios are specified for PIN service switch:
- PIN service switch with PIN server support
- PIN service switch without PIN Server support (e.g. using only internal PIN communication).
8.7.2 Procedure p. 91
8.7.2.1 Service switch in a PIN with PIN server support p. 91
8.7.2.1.1 General p. 91
Following procedures are supported for service switch in a PIN with PIN server support:
- PIN Service Switch procedure;
- PIN Service Switch Configure procedure.
8.7.2.1.2 PIN Service Switch procedure p. 91
Pre-conditions:
- The PIN Client established an application session with an Application Server;
- The PIN Client joined a PIN.
Step 1.
Upon reciving the PIN Service Switch response, the PIN Client validates if the request was succesful and can indicate the result to the Application Client; the PIN Client can transfer the application context to the target PIN Client. If the PIN Service Switch response indicated a failure, the PIN Client can attempt perform service switch again for the same or a different target PIN Client considering the failure reason.
The PIN Client sends a PIN Service Switch request to the PIN Server. The PIN Service Switch request includes the requestor identifier [PIN Client ID], security credential, a PIN identifier [PIN ID], an Application Client identifier [ACID], an Application Server identifier, an application session identifier, can include an IP 4 tuple that describes the traffic of the application session and can include a target PIN Client [PIN Client ID] if a target is known.
Step 2.
Upon receiving the request from the PIN Client, the PIN Server checks if the PIN Client is authorized to request service switching for the given Application Server and validates the request. If the request is authorized and valid, the PIN server can determine a target PIN Client if the target PIN Client was not included in the request. The PIN Server sends a PIN Configure Service Switch request to the PIN Management Client and the Application Server as in clause 8.7.2.1.2. The PIN Server can use the PIN ID to identify the PIN Management Client instance and the Application Server identifier, or IP 4 tuple, to identify the Application Server instance.
Step 3.
If the processing of the request was successful, the PIN Server sends a PIN Service Switch response to the PIN Client that indicates the Service Swich request was successfully processed and can include the target PIN Client information if it was decided by the PIN Server. Otherwise, the PIN Server sends a PIN Service Switch response to the PIN Client indicating that the request processing failed and can include appropriate reasons.
8.7.2.1.3 PIN Service Switch Configure procedure p. 92
Pre-conditions:
- The PIN Client successfully requested a service switch with the PIN Server
- The AS is successfully subscribed for PIN service switch notifications with the PIN server.
Step 1.
The PIN Server sends the PIN Configuration Service Switch Configure request to the PIN Management Client. The PIN Configuration Service Switch Configure request includes the requestor identifier, security credential, Application Client identifier, Application Server identifier, target PIN Client, application session identifier and can include IP 4 tuple that descibes the traffic of the application session.
Step 2.
Upon receiving the request from the PIN Server, the PIN Management Client checks if the PIN Server is authorized to request service switch configuration and validates the request.
If the request is authorized and valid, the PIN Management Client prepares for sending PIN Configure Service Switch request to the PIN Gateway Client or the target PIN Client. The PIN Management Client can use the PIN ID to identify the PIN Gateway Client instance and the target PIN Client identifier to identify the target PIN Client.
Step 3.
The PIN Management Client sends the PIN Management Service Switch Configure request to the PIN Gateway Client or the target PIN Client including the information defined in step 1.
Step 4.
Upon receiving the request from the PIN Management Client, the PIN Gateway Client or the target PIN Client checks if the PIN Managment Client is authorized to request service switch configuration and validates the request. If the PIN Management Client is authorized and the request is valid, the PIN Gateway Client or the target PIN Client use the information provided in the request to switch the application session to the target PIN Client.
Step 5.
If the processing of the request was successful, the PIN Gateway Client or the target PIN Client send a PIN management Service Switch Configure response to the PIN Management Client indicating the processing was successful. Otherwise, the PIN Gateway Client or target PIN Client send a PIN Management Service Switch Configure response to the PIN Management Client indicating that processing the request failed and can include appropriate reasons.
Step 6.
If the processing of the request was successful, the PIN Management Client or Application Server send a PIN Configuration Service Switch Configure response to the PIN Server that indicates the request was successfully processed. Otherwise, the PIN Management Client or Application Server send a PIN Configuration Service Switch Configure response to the PIN Server indicating the processing the request failed and can include appropriate reasons.
Step 7.
The PIN Server sends the PIN service switch notification to the Application Server if the procedure with the PIN Management Client was successful in step 6. The PIN service switch notification includes the PIN server identifier, PIN identifier, Application Client identifier, target PIN Client, application session identifier and can include IP 4 tuple that descibes the traffic of the application session.
Step 8.
Upon receiving the PIN service switch notification, the Application Server uses the information provided in the notification to switch the application session to the target PIN client.
8.7.2.1.4 PIN Service Switch subscription p. 94
8.7.2.1.4.1 General p. 94
The PIN service switch subscription is used by the Application Server to be notified of PIN service switch events by the PIN Server.
The PIN service switch notification events includes PIN service switch configuration information.
8.7.2.1.4.2 Procedure p. 94
Figure 8.7.2.1.4.2.1-1 illustrates the PIN service switch subscribe procedure.
Pre-conditions:
- The application server has already received the address of the PIN server;
- The application server is authorized to communicate with PIN server;
Step 1.
The application server sends the PIN service switch subscribe request to the PIN server. The PIN service switch subscribe request includes the application server identifier along with the security credentials, PIN ID, subscribed event, notification target address, and may include proposed expiration time.
Step 2.
Upon receiving the request from the application server, the PIN server checks if the application server is authorized to subscribe. The authorization check may apply to an individual PIN. If the request is authorized, the PIN server creates and stores the subscription for application server.
Step 3.
If the processing of the request is successful, the PIN server sends a PIN service switch subscribe response to the application server, which includes the subscription identifier and may include the expiration time, indicating when the subscription will automatically expire. To maintain the subscription, the application server shall send a PIN service switch update request prior to the expiration time. If a new PIN service switch update request is not received prior to the expiration time, the PIN server shall treat the application server as implicitly unsubscribed.
Figure 8.7.2.1.4.2.2-1 illustrates the PIN service switch notify procedure.
Pre-conditions:
- The application server has subscribed with the PIN server as specified in clause 8.7.2.1.4.2.1.
Step 1.
When a service switch event occurs at the PIN server that satisfies triggering conditions, the PIN server sends a server switch notification to the subscribed application servers.
Step 2.
The PIN server sends an PIN service switch notification to the subscribed application server(s) related to the service switch event and includes the PIN service switch configuration information.
The PIN service switch configuration information includes the PIN subscription identifier, subscribed event, PIN server identifier, PIN identifier, Application Client identifier, application session identifier, target PIN Client, application session identifier and can include IP 4 tuple that describes the traffic of the application session.
Step 3.
Upon receiving the notification, the application server uses the information provided in the notification to switch the application session to the target PIN client.
Figure 8.7.2.1.4.2.3-1 illustrates the PIN service switch update procedure.
Pre-conditions:
- The application server has subscribed with the PIN server as specified in clause 8.7.2.1.4.2.1.
Step 1.
The application server sends a PIN service switch update request to the PIN server. The PIN service switch update request includes the security credentials and the subscription identifier. It may also include notification target address and proposed expiration time.
Step 2.
Upon receiving the request from the application server, the PIN server checks if the application server is authorized to update the subscription information. If the request is authorized, the PIN server updates the stored subscription.
Step 3.
If the processing of the request is successful, the PIN server sends a PIN service switch update response to the application server, which may include the expiration time, indicating when the subscription will automatically expire. To maintain the subscription, the application server shall send a PIN service switch subscription update request prior to the expiration time. If a PIN service switch update request is not received prior to the expiration time, the PIN server shall treat the application server as implicitly unsubscribed.
Figure 8.7.2.1.4.2.4-1 illustrates the PIN service switch unsubscribe procedure.
Pre-conditions:
- The application server has subscribed with the PIN server as specified in clause 8.7.2.1.4.2.1.
Step 1.
The application server sends a PIN service switch unsubscribe request to the PIN server. The PIN service switch unsubscribe request includes the security credentials and the subscription identifier.
Step 2.
Upon receiving the request from the application server, the PIN server checks if the application server is authorized to unsubscribe. If the request is authorized, the PIN server cancels the subscription indicated by the subscription identifier.
Step 3.
If the processing of the request is successful, the PIN server sends a PIN service switch unsubscribe response to the application server.
8.7.2.2 Service switch in a PIN without PIN server support p. 97
In Figure 8.7.2.2-1, it describes the service switch scenario supported internal PIN.
The PINE A has the application communication with application server. And when the PINE A decides to select other alternative PINE B to apply the traffic flow, the PINE A firstly should discover a PIN and join in. And then, in the PIN, there should exist the PINE that can be hosted with the same service type as PINE A, for example, the video flow, music flow or game flow.
The PINE A can send the request to PEMC to determine the PINE B to host the application traffic. After the determination, the PEMC sends the endpoint information to PINE A and the PINE A can offload the traffic either directly to PINE B or via PEGC.
Pre-conditions:
- The UE Identifier or PIN client Identifier of PINE A or PINE B is available;
- The PIN client in PINE A or PINE B has been authorized to communicate with the PEMC;
- The PIN client in PINE B can provide the same PIN service as PINE A's traffic flow.
Step 0.
The PINE A has application layer communication with application server. And the PINE A decides to do the service switch to other PINEs. And the PINE A has already been in a PIN.
Step 1.
The PINE A trigger the PIN service discovery request towards PEMC. This request carries the list of services the PINE A wants to consume.
Step 2.
Upon receiving the request, the PEMC performs an authorization check to verify whether the PINE A has authorization to perform the operation.
Step 3.
The PEMC provides the list of PINE endpoint(s), application client endpoint(s) information that are offering the requested services to PINE A in PIN service discovery response. The PIN service can be represented by service type that PINE provides or the application client on PINE. If the request fails, the PEMC should give the failure response to indicates the cause of request failure.
Step 4.
The PINE A selects PINE B from the list of PINEs provided in the PIN service discovery response.
The PINE A sends the PIN Management Service Switch Configure request to the selected PINE B including: PIN ID, requestor ID, service information (e.g. PIN service type, PIN service feature) before performing service switch.
Step 5.
Upon receiving the request from PINE A, PINE B determines whether it can accept the service switch request and sends the PIN Management Service Switch Configure response to PINE A.
If the PIN Management Service Switch Configure response indicates failure, the PINE A may consider other PINEs in the list of PINEs provided in the PIN service discovery response received in step 3 and may perform step 4 again.
If the PIN Management Service Switch Configure response indicates success, the PINE A maintains the service towards AS and proceeds with switching the service traffic to PINE B.
Step 6.
The PINE A switches the traffic flow to PINE B via direct communication or via PEGC.
8.7.3 Information flows p. 98
8.7.3.1 General p. 98
The following information flows are specified for Service Switch:
- PIN service switch request and response
- PIN configuration service switch configure request and response
- PIN management service switch configure request and response
- PIN service discovery request and response
- PIN service switch subscribe
- PIN service switch notify
- PIN service switch update
- PIN service switch unsubscribe
8.7.3.2 PIN service switch request p. 99
Table 8.7.3.2-1 describes information elements for the PIN service switch request that is sent from the PIN client to the PIN server.
| Information element | Status | Description |
|---|---|---|
| PIN client identifier | M | Requestor identifier. |
| Security credentials | M | Security credentials of the PIN client. |
| PIN identifier | M | Identifier of the PIN. |
| Application client identifier | M | Identifier of the application client. |
| Application server identifier | M | Identifier of the application server. |
| Application session identifier | M | Identifier of the application session. |
| Application session descriptor | O | Descriptor of application traffic flows (e.g., IP 4 tuple). |
| Target PIN client identifier (see NOTE) | O | Target PIN client identifier. |
|
NOTE:
Only if target PIN client is known.
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8.7.3.3 PIN service switch response p. 99
Table 8.7.3.3-1 describes information elements for the PIN service switch response.
| Information element | Status | Description |
|---|---|---|
| Successful response (see NOTE 1) | O | Indicates that the request was successful. |
| > Target PIN client identifier (see NOTE 2) | O | Target PIN client identifier. |
| Failure response (see NOTE 1) | O | Indicates that the request failed. |
| > Cause | O | Indicates the cause of the request failure. |
|
NOTE 1:
Only one of the IE must be included in the response.
NOTE 2:
Only if target PIN client is not provided in the PIN service switch request.
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8.7.3.4 PIN configuration service switch configure request p. 99
Table 8.7.3.4-1 describes information elements for the PIN configuration service switch configure request that is sent from the PIN server to the PIN management client and the application server.
| Information element | Status | Description |
|---|---|---|
| PIN server identifier | M | Requestor identifier. |
| Security credentials | M | Security credentials of the PIN server. |
| PIN identifier | M | Identifier of the PIN. |
| Application client identifier | M | Identifier of the application client. |
| Application server identifier (see NOTE 1) | O | Identifier of the application server. |
| Application session identifier | M | Identifier of the application session. |
| Application session descriptor | O | Descriptor of application traffic flows (e.g., IP 4 tuple). |
| Target PIN client identifier (see NOTE 2) | M | Target PIN client identifier. |
|
NOTE 1:
The IE is present if the request is sent to the PIN management client.
NOTE 2:
The IE is present if the request is sent to the application server.
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8.7.3.5 PIN configuration service switch configure response p. 100
Table 8.7.3.5-1 describes information elements for the PIN configuration service switch configure response.
| Information element | Status | Description |
|---|---|---|
| Successful response (see NOTE) | O | Indicates that the request was successful. |
| Failure response (see NOTE) | O | Indicates that the request failed. |
| > Cause | O | Indicates the cause of the request failure. |
|
NOTE:
Only one of the IE must be included in the response.
|
||
8.7.3.6 PIN management service switch configure request p. 100
Table 8.7.3.6-1 describes information elements for the PIN management service switch configure request that is sent from the PIN management client to the PIN gateway client and the target PIN client.
| Information element | Status | Description |
|---|---|---|
| PINE identifier | M | Requestor identifier. |
| Security credentials | M | Security credentials of the PIN management client. |
| PIN identifier | M | Identifier of the PIN. |
| Application client identifier | M | Identifier of the application client. |
| Application server identifier | M | Identifier of the application server. |
| PIN gateway client identifier (see NOTE 1) | O | Identifier of the PIN gateway client. |
| Application session identifier | M | Identifier of the application session. |
| Application session descriptor | O | Descriptor of application traffic flows (e.g., IP 4 tuple). |
| Target PIN client identifier (see NOTE 2) | O | Target PIN client identifier. |
| Service information (see NOTE 3) | O | PIN service type and PIN service feature. |
|
NOTE 1:
The IE is present if the request is sent to the target PIN client.
NOTE 2:
The IE is present if the request is sent to the PIN gateway client.
NOTE 3:
The IE is present if the request is sent to the PINE.
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8.7.3.7 PIN management service switch configure response p. 100
Table 8.7.3.7-1 describes information elements for the PIN management service switch configure response.
| Information element | Status | Description |
|---|---|---|
| Successful response (see NOTE) | O | Indicates that the request was successful. |
| Failure response (see NOTE) | O | Indicates that the request failed. |
| > Cause | O | Indicates the cause of the request failure. |
|
NOTE:
Only one of the IE must be included in the response.
|
||
8.7.3.8 PIN Service Discovery Request p. 101
Table 8.7.3.8-1 shows the informational elements of the PIN Service Discovery Request sent by a PIN Element to the PEMC to discover the candidate PINEs that can provide the certain PIN service.
| Information element | Status | Description |
|---|---|---|
| PIN ID | M | The identifier of the PIN. |
| Requester PINE ID | M | The identifier of the PIN Element making the request. |
| Security credentials | M | Security credentials resulting from a successful authorization for the PIN service. |
| MAC address/IP address | O | MAC address/IP address of PINE/PEMC. |
| Request PIN service type | M | List the PIN service type that the PINE request to determine the targe PINE for service switch. |
8.7.3.9 PIN Service Discovery Response p. 101
Table 8.7.3.9-1 shows the informational elements of the PIN Service Discovery Response sent by a PEMC to the PINE to list the candidate PINEs that can provide the target PIN service. The candidate PINEs that can provide the target PIN service may be multiple.
| Information element | Status | Description |
|---|---|---|
| Successful response | O | Indicates that the PIN Service Discovery request was successful. |
| > PINE ID(s) | M | The identifier of the PIN Elements that can provide the target PIN service. |
| > MAC address(es)/IP address(es) | M | MAC address/IP address of PINEs that can provide the target PIN service. |
| Failure response | O | Indicates that the PIN Service Discovery request failed. |
| > Cause | M | Provides the cause for PIN Service Discovery request failure. |
8.7.3.10 PIN service switch subscribe request p. 102
| Information element | Status | Description |
|---|---|---|
| Application server ID | M | Unique identifier of the application server. |
| Security credentials | M | Security credentials resulting from a successful authorization for the PIN service. |
| PIN ID | M | The identifier of PIN. |
| Subscribed event | M | Identifies event type for which the subscriber is notified.
Event types:
|
| Notification Target Address | M | The Notification target address (e.g., URL) where the notifications destined for the application server should be sent. |
| Proposed expiration time | O | Proposed expiration time for the subscription. |
8.7.3.11 PIN service switch subscribe response p. 102
| Information element | Status | Description |
|---|---|---|
| Successful response (see NOTE) | O | Indicates that the subscription request was successful. |
| > Subscription ID | M | Subscription identifier corresponding to the subscription. |
| > Expiration time | O | Indicates the expiration time of the subscription. To maintain an active subscription, a subscription update is required before the expiration time. |
| Failure response (see NOTE) | O | Indicates that the subscription request failed. |
| > Cause | O | Indicates the cause of subscription request failure. |
|
NOTE:
One IE is included in the response.
|
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8.7.3.12 PIN service switch notify p. 102
Table 8.7.3.12-1 describes information elements in the PIN service switch notification from the PIN server to application server.
| Information element | Status | Description |
|---|---|---|
| PIN subscription identifier | M | Identifier of the subscription. |
| Subscribed event | M | Identifies the event type as described in Table 8.7.3.10-1 for which the notification is sent. |
| PIN server identifier | M | Identifier of the PIN server sending the notification. |
| PIN identifier | M | Identifier of the PIN. |
| Application client identifier | M | Identifier of the application client. |
| Application session identifier | M | Identifier of the application session. |
| Application session descriptor | O | Descriptor of application traffic flows (e.g., IP 4 tuple). |
| Target PIN client identifier | M | Target PIN client identifier. |
8.7.3.13 PI service switch update request p. 103
| Information element | Status | Description |
|---|---|---|
| Subscription ID | M | Subscription identifier corresponding to the subscription. |
| Security credentials | M | Security credentials resulting from a successful authorization for the PIN service. |
| PIN ID | O | PIN identifier. |
| Subscribed event | O | Identifies the event type as described in Table 8.7.3.10-1 for which the subscriber is notified. |
| Notification Target Address | O | The Notification target address (e.g., URL) where the notifications destined for the application server should be sent to. |
| Proposed expiration time | O | Proposed expiration time for the subscription. |
8.7.3.14 PIN service switch update response p. 103
| Information element | Status | Description |
|---|---|---|
| Successful response (see NOTE) | O | Indicates that the subscription update request was successful. |
| > Expiration time | O | Indicates the expiration time of the subscription. To maintain an active subscription, a subscription update is required before the expiration time. |
| Failure response (see NOTE) | O | Indicates that the subscription update request failed. |
| > Cause | M | Indicates the cause of subscription update request failure. |
|
NOTE:
One IE is included in the response.
|
||
8.7.3.15 PIN service switch unsubscribe request p. 103
| Information element | Status | Description |
|---|---|---|
| Subscription ID | M | Subscription identifier corresponding to the subscription. |
| Security credentials | M | Security credentials resulting from a successful authorization for the PIN service. |
8.7.3.16 PIN service switch unsubscribe response p. 103
| Information element | Status | Description |
|---|---|---|
| Successful response (see NOTE) | O | Indicates that the unsubscribe request was successful. |
| Failure response (see NOTE) | O | Indicates that the unsubscribe request failed. |
| > Cause | M | Indicates the cause of unsubscribe request failure. |
|
NOTE:
One IE is included in the response.
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8.7.4 APIs p. 104
8.7.4.1 General p. 104
Table 8.7.4.1-1 illustrates the API for AS service switch subscription.
| API Name | API Operations | Operation Semantics | Consumer(s) |
|---|---|---|---|
| Ppinserver_ | Subscribe | Subscribe/Notify | AS |
| Notify | |||
| Update | |||
| Unsubscribe |
8.7.4.2 Ppinserver_ ASServiceSwitch_Subscribe operation p. 104
API operation name:
Ppinserver_ASServiceSwitch_Subscribe
Description:
The consumer subscribes for service switch information.
Inputs:
See clause 8.7.3.10.
Outputs:
See clause 8.7.3.11.
See clause 8.7.2.1.4.2.1 for details of usage of this operation.
8.7.4.3 Ppinserver_ ASServiceSwitch_Notify operation p. 104
API operation name:
Ppinserver_ASServiceSwitch_Notify
Description:
The consumer is notified with service switch information.
Inputs:
See clause 8.7.3.12.
Outputs:
None.
See clause 8.7.2.1.4.2.2 for details of usage of this operation.
8.7.4.4 Ppinserver_ ASServiceSwitch_ Update operation p. 104
API operation name:
Ppinserver_ASServiceSwitch_Update
Description:
The consumer updates an existing subscription for service switch information.
Inputs:
See clause 8.7.3.13.
Outputs:
See clause 8.7.3.14.
See clause 8.7.2.1.4.2.3 for details of usage of this operation.
8.7.4.5 Ppinserver_ ASServiceSwitch_ Unsubscribe operation p. 104
API operation name:
Ppinserver_ASServiceSwitch_Unsubscribe
Description:
The consumer cancels an existing subscription for service switch information.
Inputs:
See clause 8.7.3.15.
Outputs:
See clause 8.7.3.16.
See clause 8.7.2.1.4.2.4 for details of usage of this operation.
