Intelligent Networking • Overview • Conceptual models • Example services • Configuration • Programming Interface • Programming examples • Example program • Debugging
IN - Introduction • The Intelligent Network Architecture to quickly create and deploy customer SERVICES Supports many services Is a standard - multi-vendor Distributed platform • Example services supported by IN Freephone Premium Rate Voice mail Call Diversion Call baring Local Number Portability UPT
The pre-IN years... • Local switch (service user access point) is monolithic and proprietary • Local switch supports switching, call processing and database processing • The same functionality may be duplicated between multiple nodes • Different implementations create inter-working problems make enhancements complex • The network operator is unable to quickly respond to customer requests
SSP SSP SSP Pre-IN free-phone service 800 translation database Special ‘800’ exchange 800 number is translated and forward routed to destination Network routes call (signalling and voice) to special free phone exchange/ server Caller dials free-phone 800 number1-800-1234567 PSTN Local exchange Local exchange 1-755-997612
IP SSP SCP SSP Classic IN physical Architecture Service Control PointControl and database functions SCEP/SMP Intelligent PeripheralPlay-back announcements X.25 Service Creation Environment Point/Service Management PointService administration SS7 SS7 SS7 PSTN SS7 Service Switching Point - physical circuit switching
Function of the IN SSP • Point of subscription for the service USER (this is not necessarily the SUBSCRIBER) • IN features Detection of IN calls Generation and transmission of queries a SCP Generate and transmit state information to the SCP (B-party busy, B-party no answer) Record and transmit statistics to the SCP Process SCP requests and replies Service filtering
Function of the IN SCP • Parameter (service) validation and authentication • Process requests from SSP, send responses • Call routing, parameter, time, service, subscriber dependant • Control IP to play back standard announcements
Function of the IP • The functionality integrated into a Service Switching Point often provides restricted capabilities only, the main application being targeted towards general announcements. • IPs are dedicated to user interaction. They provide high storage capacity together with numerous functions: Standard announcements Information collection via DTMF Speaker independent voice recognition Customized announcements Fast modification/customization of announcements Speaker dependent voice recognition Complex dialogues controlled via internal scripts Provision of conferencing resources (defined in CS-2)
Function of the SCEP/SMP • Service Administration • Development and introduction of new services • Modification of exsisting services • Provides a Service Creation Environment (generally a graphical interface)
Generalised IN call flow • User communicates with the SSP (dials the called party number). • The SSP analyses the number and determines that this is an IN call. • The SSP contacts the SCP to determine how the call should continue. • The SCP can optionally obtain further caller information by instructing the IP to play back announcements (I.e. to collect PIN). • The SCP instructs the SSP on how the call should continue, modifying call data as appropriate to any subscribed services.
IP SSP SCP SSP Simplified IN Call 2 & 5. How should the call be processed? 4 Announcement 3 & 6. Instructions 1. Off hook and dial number SS7 Network 7. Call progressed through to destination
SSP SCP SSP SSP SSP Freephone service Example Multipledestinations 2,6 3 1 4 5
Freephone Service 1. Calling party dials the freephone number (e.g. 0800 123456). 2. A trigger set in the SSP causes an INAP query to be sent to the SCP, containing the called and calling party information. On reception of the Query, the SCP translates the freephone number to the ‘best fit’ destination. 3. The SCP sends the destination number back to the SSP and requests return of charging information once the call has completed. 4. The SSP resumes call processing with the new destination address, routing the call over the PSTN. 5. The call is established. 6. After the call is terminated, the SSP sends charging information to the SCP.
IP SSP SCP SSP Televoting service Example 2,5 4 3,6 1
Televoting example 1. Calling party dials the televoting number. 2. Switch recognises televoting call and sends a query to the SCP. The SCP analyses the dialled number and increments the appropriate vote count. The SCP determines that a prompt indicating successful registration of the vote is required. 3. The SCP sends a routing number of an appropriate IP able to play the televoting announcement. The IP plays the announcement. 4. The IP informs the SSP that the announcement has been played and is complete. 5. The SSP sends the completion status to the SCP 6. The SCP instructs the SSP to clear the call.
IP SSP SCP SSP Televoting service method (2) 1,3 3 4 2
Televoting service method (2) 1 SCP initiates service filtering (televoting) at the SSP 2 Subscriber dials, SSP informs SCP that the specified service has been activated 3 SCP instructs the SSP to play an announcement (using the IP) and release the call once the announcement has completed. 4 After a specified time, or at specific defined time intervals set when the service was activated, the SSP reports the televote count to the SCP. Steps 2 and 3 may be repeated many times!
IN CS-1 Benchmark services See Q.1219 Annex A for example service flows Abbreviated Dialing (ABD) Attendant (ATT) Authentication (AUTC) Autorisation Code (AUTZ) Automatic Call Back (ACB) Call Distribution (CD) Call Forwarding (CF) Call Forwarding on Busy/Don’t Answer Call Gapping (GAP) Call Hold with Announcement (CHA) Call Limiter (LIM) Call Logging (LOG) Call Queuing (QUE) Call Transfer (TRA) Call Waiting (CW) Closed User Group (CUG) Consultation Calling (COC) Customer Profile Management (CPM) Customized Recorded Announcement (CRA) Customized Ringing (CRG) Destination User Prompter (DUP) Follow-Me Diversion (FMD) Mass Calling (MAS) Meet-Me Conference (MMC) Multiway Calling (MWC) Off-Net Access (OFA) Off-Net Calling (ONC) One Number (ONE) Origin Dependent Routing (ODR) Originating Call Screening (OCS) Originating User Prompter (OUP) Personal Numbering (PN) Premium Charging (PRMC) Private Numbering Plan (PNP) Reverse Charging (REVC) Split Charging (SPL) Terminating Call Screening (TCS) Time Dependent Routing (TDR)
Types of IN signalling • Between SSPs: To directly control circuit switched connection or exchange information relating to a call that is in progress on a switched circuit (56 or 64kb/s) - Circuit related • Between SSP and SCP: To exchange control information, no physical bearer circuit exists between the SSP and SCP. This is non-circuit related or transaction based signalling. • Between SSP and IP, and SCP and IP: May be ISUP, INAP or proprietary.
ISUP SCCP MTP TCAP INAP INAP TCAP SCCP INAP TCAP SCCP MTP Protocol Model SSP IP SCP ISUP MTP Note: There may also be an ISDN link between the SSP and IP
ISUP • To directly control switched circuit channels. • Defines message formats, message sequences.
SCCP • Signalling Connection Control Part • A ‘thin’ protocol layer allowing data to be exchanged between intelligent entities (sub-systems) through the SS7 network. • Provides routing and addressing control. • Each entity that communicates using SCCP is identified by its point code and sub-system number (or global title). • Communication may be session based (connection oriented SCCP) or connectionless
TCAP (or TC) • Transaction Capabilities Application Part • Provides a structure for the invocation of operations at remote intelligent entities. • An exchange of messages is called a transaction at the SCCP interface and a dialogue at the INAP interface. • Unstructured dialogue - non session based, uses TC-UNI messages • Structured dialogue - session based, requires BEGIN, CONTINUE, END. • INAP uses structured dialog only. • Operations and their results are conveyed in ‘components’ within each dialogue.
TCAP control state machines Dialogue handling Establishment, maintenance and close down of dialogues Each dialogue is identified by a dialogue_id. Component handling One state machine per invoked operation on the invoking side Each operation is identified by an invoke_id. Operation timer Controls the duration of a invocation state machine.
Communication TCAP & TCAP-User TC User 1. 1. Single Components (primitives) 2. Collect Components 3. All collected components of one dialog in one message Component Sublayer 2. Transaction Sublayer 3. TCAP message SCCP MTP
TCAP dialogue primitives TC-Begin.Req; TC-Begin.Ind TC-Continue.Req; TC-Continue.Ind TC-End.Req(Basic); TC-End.Ind(Basic) TC-End.Req(Prearranged): Local termination of the transaction TC-User-Abort.Req; TC-User-Abort.Ind: ‘User Information’ informs about abort reasons (normal abort, error indication) TC-Provider-Abort.In: Sent by the transaction sub-layer of TCAP TC-Notice.Ind: Requested SCCP service was not available
TCAP component primitives TC-Invoke.Req / Ind TC-Result.Last.Req / Ind TC-User-Error.Req / Ind TC-User-Reject.Req / Ind TC-Local-Reject.Ind / TC-Remote-Reject.Ind: Errors detected by TCAP: Those errors are indicated to the user. The user decides whether the error shall be sent to the peer entity or not (controlled by sending the respective dialog handling primitive) TC-Cancel.Req: TCAP user requests locally the abort of a previously invoked operation and the cancellation of the related state TC-Cancel.Ind: Indication of an operation timer expiration to the local TCAP user. (Interpretation by the TCAP user depends on the operation class!)
IN Conceptual Model Four planes (Q.120x) are used to model and abstract the IN functionality: Q.1202 - Service Plane (SP) Uppermost, describes services from the users perspective. Hides details of implementation from the user Q.1203 - Global Functional Plane (GFP) contains Service Independent Building Blocks (SIBs), reusable components to build services Q.1204 - Distributed Functional Plane (DFP) models the functionality in terms of units of network functionality, known as Functional Entities (FEs). The basis for IN execution in the DPF is the IN Basic Call State Model. Q.1205 - Physical Plane (PP) Real view of the physical network.
SP/GFP Service feature Service Service Plane Q.1212(Not defined!) One number Reverse charging Global FunctionalPlane Translate Screen Q.1213 Basic call process Charging SIB
SIBs A SIB has the following characteristics: • Exists in the Global Functional Plane. • It is a re-useable building block, defining a complete activity. • It has a defined interface, with a specified number of inputs and outputs. • It is independent of the physical implementation. • SIBs are independent of the IN Services. • SIBs are combined to implement a Service. • CS-1 SIB examples: Authenticate, Charge, Log Call Information,Screen. • Some Service Creation Environments operate on SIBs
BCP and POI • Special SIB called the Basic Call Process (BCP). • This interacts with the other SIBs. • The GFP defines the Point of Initiation (POI) and the Point of Return (POR) between the BCP and any other SIB or sequence of SIBs. CS-1 Points of Initiation Call originatedAddress collectedAddress analysedCall arrivalBusyNo AnswerCall acceptanceActive stateEnd of call CS-1 Points of Return Continue with existing dataProceed with new dataHandle as transitClear callProvide call party handlingInitiate call
Freephone modeling with CS-1 SIBs Charge_1 (Calling free of charge) Charge_2 (Record for subscriber) Translate Translate UI Translate SIB Chain 1 SIBChain 2 SIBChain 3 SIBChain 4 POI Address Analyzed POR Proceed with new data POI Busy POR Proceed with new data POI No Answer POR Proceed with new data POI No Answer POR Clear Call BCP Service Features Calling line is set free of charge The service subscriber is to be charged The first call attempt shall be routed to an alternative destination if the first destination is busy or does not answer, i.e. rerouting on “busy” or “no answer” If a re-routed call, i.e. due to “busy” or “no answer” during the first attempt, meets a “no answer” situation then an announcement shall be played to the caller. This means that the “busy” situation shall not be monitored for during the second attempt.
Basic call process GFP/DFP (For CS-1) Global FunctionalPlane Q.1213 POI SIB n SIB n POR DistributedFunctional Plane BCM SCF Q.1214 SSF SDF CCF SRF Functional Entity
Functional Entities • Basic Call handling Call Control Agent Functions (CCAF) - models the users telephone Connection Control Function (CCF) - basic switching Specialised Resource Function (SRF) - additional media management • Service Execution Functions Service Switching Functions (SSF) - interface to SCF Service Control Function (SCF) - service logic Service Data Function (SDF) - service data SRF • Service Management Functions System Management Functions (SMF) - service provisioning, maintenance Service Management Agent Functions (SMAF) - MMI for SMF service Creation Environment Function (SCEF) - specification and testing
CCF/SCF SCF SRF SDF Authenticate Algorithm Charge Compare Distribution Limit Log Call Information Queue Screen Service Data Mgt Status Notification Translate User Interaction Verify Basic Call Process FE and SIB association (CS-1)
DFP and the Physical Plane DistributedFunctional Plane SCF Q.1214 SRF SDF SSF Functional Entity SCP Physical Plane Q.1215 SDF SSP IP INAP Communication
CS1 physical FE distribution SCP SMAF SCF Voice Transport SMF Signaling SDF IP SCEF Optional FE SMP SDF SRF SDP SN SCF SRF SCF SSF SSF CCF CCF SDF CCAF SDF SRF SSP SS7 Network
FE definition of IP and SN Intelligent Peripheral • An IP (Intelligent Peripheral) contains the Specialized Resource Function only, i.e. an IP provides capabilities necessary for services with user dialogues • An IP is controlled by the service logic Service Node • A Service Node (SN) comprises all functions needed to provide services (Service Control Function, Service Data Function, Service Switching Function, Call Control Function and Specialized Resource Function • A Service Node is able to provide complete services independent on other networks components • Service Nodes may be also called Intelligent Network in a Box • The mentioned functions represent the minimum function set of a Service Node. Obviously there are additional functions useful concerning management, service creation and other areas.
Service Node architecture INAP to SCP MAP to HLR Management SCEF INAP to SSP SCF SDF SSF/ CCF Bearer Control (DSS1 or ISUP) SRF
SN features • Internal proprietary interfaces between its components • The service logic can directly access the voice channel • Besides voice now numerous data communication protocols and applications may be used • Flexible, efficient and cheap (good cost performance ratio) implementation of services for small service providers • Easy introduction into existing networks based on connection via standard signaling protocols (EDSS1, ISUP) • Reduction of #7 signaling load • Lower traffic concentration
Example SN capabilities • Voice messaging subscribers record own messages which are distributed through the network (according to a distribution list). • Fax messaging Record fax messages during busy hour to retransmit during off-peak charing period. • Short Message Service Gateway to email networks. • Electronic mail
Basic call process Service Modelling in the CS-1 DFP • SIBs are modelled in the DFP by interactions between Functional entities. • Each SIB is modelled by the SCF controlling other FE’s. • The BCP is modelled in the DFP by the Basic Call State Model in the CCF. SIB n SIB n SCF CCF SSF SDF
The Basic Call State Model • BCSM • Standard definition of call processing states and events • Switch and manufacturer independent • Trigger Detection Points are pre-defined in both the Originating Basic Call State Model OBCSM and the Termination Basic Call State Model (TBCSM) • Non-interruptable sequences of processing are called Points-In-Call (PIC)
IN Triggers • A normal call becomes an ‘IN call’ if a special condition is recognised during the call handling • Recognition of such a condition ‘triggers’ a query to an external control component (SCP) • Recognition takes place at pre-defined Detection Points in the call handling, which may be armed (active) or not armed (inactive) • DPs may be armed statically for a long period to implement a particular IN Service. • DPs may be armed dynamically to report particular events and errors.
Types of Triggers • Two types of processing on satisfying a DP: Suspend call processing and request instructions Request : TDP_R Continue Call processing and issue Notification to SCF Notification : TDP_N
9 2 8 7 6 5 1 4 3 CS-1 originating BCSM O_Abandon 1. O_Null & Authorise Origination_Attempt 6. O_Exception 10 Orig_attempt Authorised Point in Call (PIC) 2. Collect_info Collected_info Detection Point (DP) 3. Analyse_info Route_select_failure Analysed _info O_Called_party_busy 4. Routing_&_alerting O_No_Answer O_Answer 5. O_Active O_Mid_call O_Disconnect
OBCSM Triggers • DP1 : Origination_attempt_authorized Call setup is recognized and authorized. • DP2 : Collected_Information Pre-defined number of dialed digits is collected • DP3 : Analyzed_Information Dialed digits are analyzed • DP4 : Route_Select_Failure Routing failed : no free channel, dialed number not available, network overload • DP5 : O_Called_Party_Busy Destination busy • DP6 : O_NO_Answer Caller does not answer in predefined time, Service Logic specifies the “no answer time” for SSP • DP7 : O_Answer Called subscriber answers: SSP receives e.g. an ANM • DP8 : O_Mid_Call Signal (hook flash, F-key) recognized during call • DP9 : O_Disconnect A or B side hangs up • DP10 : O_Abandon Call set-up discontinued by the A-side
17 15 14 13 16 12 CS-1 Terminating BCSM T_Abandon 7. T_Null & Authorise termination attempt 11. T_Exception 18 Term_attempt Authorised T_Called_Party_busy Point in Call (PIC) 8. Select Facility &Present Call Detection Point (DP) T_No_Answer 9. T_Alerting T_Answer 10. T_Active T_Mid_call T_Disconnect
TBCSM Triggers • DP12 : Termination_attempt_authorized an incoming call attempt is recognized and authorized • DP13 : T_Called_Party_Busy Destination busy • DP14 : T_No_Answer Called party does not answer during a given time • DP15 : T_Answer Called line answers, I.e. the SSP receives the ANM • DP16 : T_Mid_Call Signal (e.g. hook flash, function key) is recognized during the active connection • DP17 : T_Disconnect Either A-side or B-side hangs up • DP18 : T_Abandon Call set-up aborted by the A-side, can happen at any time and is considered normal