This feature determines the transferable set for access transfer .
The transferable set is a phrase from 3GPP 24.237, and includes sessions that will be transferred during an access transfer, and those that are considered superfluous.
Feature cheat sheet
| B2BUA Instance | SAS Support | Originating / Terminating | Point(s) in Session Plan | Network Operator Data | Subscriber Data | Stateful or Stateless | POJO or SBB Feature | Other notes |
|---|---|---|---|---|---|---|---|---|
SCC |
Yes |
Both Originating and Terminating |
SCCAccessTransfer_SipAccess_SessionStart |
None |
None |
Stateless |
POJO |
Session input and output variables
Session input variables
| Variable | Type | Description |
|---|---|---|
AccessTransferType |
AccessTransferType (Enum) |
This feature will only run when this field is set to |
ASURI |
String |
The SIP URI of the current node |
Session output variables
| Variable | Type | Description |
|---|---|---|
MostRecentlyActive |
TrackedSession (POJO) |
Contains all the information in TrackedDialogKeys about the most recently active session |
SuperfluousSessions |
Set<TrackedSession> |
A set of all of the other sessions found from querying the TrackedDialogKeys table |
AccessTransferIsLocal |
boolean |
True if the MostRecentlyActive’s ASURI field is the same as the current nodes ASURI |
Statistics
SCCDetermineTransferableSet statistics are tracked by the sentinel.volte.sip SBB
and can be found under the following parameter set in REM:
SLEE-Usage → sentinel.volte.sip service → sentinel.volte.sip SBB → feature → SCCDetermineTransferableSet
or with rhino-stats:
"SLEE-Usage.Services.ServiceID[name=sentinel.volte.sip,vendor=OpenCloud,version=3.1.0].SbbID[name=sentinel.volte.sip,vendor=OpenCloud,version=3.1.0].feature.SCCDetermineTransferableSet"
| Name | Description |
|---|---|
Started |
Incremented each time the feature runs |
FailedToStart |
Incremented when a fatal error occurs before feature execution |
IssuedWarning |
Incremented when a non-fatal error occurs during feature execution |
FailedDuringExecution |
Incremented when a fatal error occurs during feature execution |
TimedOut |
Incremented when feature execution does not complete within a reasonable time frame |
SessionOwnershipQuery |
Incremented when the feature sends a query to the session ownership facility |
SessionOwnershipError |
Incremented when a TrackedDialogKeys lookup fails with a Session Ownership error |
SessionOwnershipSuccess |
Incremented when a TrackedDialogKeys lookup returns successfully |
SessionOwnershipNoDataFound |
Incremented when no matching tracked dialog keys entries were found in the session ownership facility |
FoundTrackedSession |
Incremented when the feature successfully finds a Session Ownership Record resulting from a TrackedSession |
SavedSessionToTransfer |
Incremented when the feature saves the most recently active TrackedSession to session state |
SavedSuperfluousSessions |
Incremented when the feature saves all of the remaining TrackedSession’s to session state |
SessionOwnershipAsyncQueryTimeSuccess |
Samples the elapsed time between starting a query and a success response arriving from the session ownership facility |
SessionOwnershipAsyncQueryTimeFailure |
Samples the elapsed time between starting a query and a failure response arriving from the session ownership facility |
Behaviour
This feature uses the P-Asserted-Identity header from the handover INVITE as an "additional key" to look up a Session Ownership Record.
Prior sessions for the purposes of SCC write Session Ownership Records saved by the
AccessLegTracking and External Session Tracking features.
Each returned Session Ownership Record is converted into an API object named TrackedSession.
The TrackedSession with the most recent LastActiveTime is stored in Session State as the MostRecentlyActiveSession.
All other Tracked Sessions are stored in the SuperfluousSessions set.
The feature sets the AccessTransferIsLocal flag in Session State if the MostRecentlyActiveSession has an OwnerURI value the same as the current node’s ASURI.
