Table Of Contents
Numbering Plans and Dialing Procedures
E.164 Dialing Plan Implementation
Dial 1 Options for Local, Toll, and InterLATA Calls
Directory Services (411, 555-1212, and 0+ Listing Services)
Information Service Calls (900 and 976)
n11 support (211, 311, 411, 511, 611, 711, 811)
Community Information and Referral Services (211)
Traffic and Transportation Information (511)
Telecommunications Relay Services (711)
NRUF Reporting for NANPA Audit Support
Important Provisioning Requirements
Emergency 911 Trunk Connection Loss Alarm
Sequence of Events for 911 Ring Back
Numbers Used to Access Operator Services
Busy Line Verification (BLV) and Operator Interrupt (OI) Services
BLV/OI over SIP Trunk between BTS 10200 Nodes
Technical Description of SIP Triggers
Terminology Used in this Section
Off-Hook Trigger (Delayed and Immediate)
OHD Treatment for MGCP/NCS Subscribers
OHD Treatment for SIP Subscribers
Termination Attempt Triggers (TAT_1 and TAT_2)
Feature Interactions for OHD Trigger
Feature Interactions for TAT_1 and TAT_2 Triggers
Active Call Information Display
Alerting Notification to Third-Party Feature Server
Calling Party Number Options for Outbound SETUP Messages
Option to Send Billing DN as CPN for Outbound Calls
Option to Send Billing DN as CPN for Emergency Calls
Option to Send Redirecting Number as CPN for Redirected Calls
Dialing Parity (IntraLATA Toll Presubscription)
Local Number Portability (LNP)
DTMF Relay Based on RFC 2833—Call Agent Controlled Mode
Availability of Legacy Behavior
Conditions for Sending LCO for RFC 2833 Telephone-Events
T.38 Fax Relay, Modem, and TDD Handling
Understanding the Fax, Modem, and TDD Handling Feature
SDP Attributes Support for T.38 Fax Relay
MTA DQOS Support for T.38 Fax Relay
Fallback to Audio Media when T.38 Negotiation Fails
Audio Restore After Successful T.38 Fax Transmission
SDP Attributes Encoding Formats
Near End Test Origination Test Calls
Testing Capability for 911 FGD-OS Trunks
Network Loopback Test for NCS/MGCP Subscriber Endpoints
Network Loopback Test for ISDN PRI Trunks
Network Features
Revised: November 18, 2008, OL-15337-05Introduction
The Cisco BTS 10200 Softswitch supports network features as described in the following sections:
•
Numbering Plans and Dialing Procedures (includes information on digit manipulation, E.164 dialing plan, casual dialing (dial around), dial 1 options, directory services, easily recognizable codes, Information service calls (900 and 976), n11 support (211, 311, 411, 511, 611, 711, 811). and NRUF reporting)
•
•
•
•
•
•
In general, BTS 10200 features delivered by gateway clients behave identically to their public switched telephone network (PSTN) counterparts.
Note
Note
For subscriber features, see Chapter 3, "Subscriber Features."
For outgoing call restrictions see Chapter 4, "Class of Service Restrictions and Outgoing Call Barring Features."Some features can be accessed and controlled by the subscriber using a handset and vertical service codes (VSCs). VSCs are provisionable by the service provider, and the customary values are country specific. The VSC values used throughout this chapter are for illustration purposes. For convenience, some VSC values are preprovisioned in the BTS 10200. The valid formats for VSC ASCII strings are listed in the VSC table in the Cisco BTS 10200 Softswitch CLI Database. To view the current VSC values provisioned on your system, use the show vsc CLI command. To provision VSCs, see the VSC provisioning procedure in the Provisioning Guide.
Typically, the system responds to user handset actions by providing an appropriate announcement. However, if an announcement is not provisioned or cannot be played, an alternate tone (for example, a reorder tone) is played. Announcements are listed in the Provisioning Guide, and tones are listed in the Operations and Maintenance Guide.
Interoperability
The BTS 10200 interworks with a wide range of network elements (NEs), but there are certain limitations. we recommend that you keep the following caution in mind as you prepare to purchase and use NEs for your network.
Caution
Numbering Plans and Dialing Procedures
The BTS 10200 supports the numbering plans and dialing procedures listed in Table 1-1. These features are described in the sections that follow.
Note
Digit Manipulation
The digit manipulation (DIGMAN) feature allows you to modify both calling number and called number for both incoming and outgoing calls within the BTS 10200.
Tip
You can use the DIGMAN feature to modify the nature of address (NOA) of ANI and/or DNIS numbers. This feature provides the following benefits in the service provider network:
•
•
•
For additional standards information, see the following industry sources:
•
•
The BTS 10200 performs digit manipulation by matching and replacing digits in the digit string that is being processed.
E.164 Dialing Plan Implementation
The BTS 10200 implements a dialing plan based on ITU-T Recommendation E.164, The International Public Telecommunication Numbering Plan, a standard for numbering and routing. This dialing plan uses a generic numbering scheme for number evaluation. The BTS 10200 performs digit manipulation on ANI data of the calling party, and on DNIS data of the called party.
National Number
In the E.164 numbering scheme, there are three parts to any national number (number that terminates within the country):
•
•
•
The combination [EC + DN] is called the subscriber number (SN).
The combination [NDC + EC + DN], or [NDC + SN], is called the national number (NN).[NDC + EC + DN] is interpreted as [NPA + NXX + XXXX] in NANP, where NPA (numbering plan area) = 200 to 999, NXX (office code) = 200 to 999, and XXXX = 0000 to 9999. The BTS 10200 applies the NANP interpretation if the NANP-DIAL-PLAN flag is set to Y (yes) in the DIAL-PLAN-PROFILE table.
A subscriber originates a call by dialing as follows:
•
•
•
Examples of national prefixes include:
–
–
–
–
For countries that do not use NDCs, it is not necessary to provision any value for the NDC parameter in the BTS 10200.
International Number
The international number is the number dialed in one country to reach a subscriber in another. Each country is assigned a country code (CC). The international number is the combination [CC + NN], or [CC + NCD + EC + DN]. Table 1-2 lists several examples.
To place a call to a phone in another country, the caller must dial an international prefix and then the international number. Thus, the complete digit string to dial is [international prefix + CC + NN]. The international prefix varies from country to country. Examples of international prefixes include:
•
Example of a call from China to Montreal: 00-1-514-870-xxxx
•
Example of a call from the United States to Bruxelles: 011-32-02-123-xxxx
In some countries, two or more international prefixes might be used
•
•
Casual Dialing (Dial Around)
Casual dialing, also known as dial around, is a feature that allows subscribers to make 101XXXX calls. In the BTS 10200 implementation, the digit map CLI command tokens provide the digit pattern. The digit pattern specifies all possible acceptable patterns. An example of a casual digit pattern is 1010321 or 1010220. The digit map table tells the media gateway (MGW) how to collect and report dialed digits to the Call Agent (CA). Subscribers can prefix their toll, interLATA, or international calls with 101XXXX. Casual dialing supports the following casual calls:
•
•
•
Dial 1 Options for Local, Toll, and InterLATA Calls
The service provider can provision the system to control the use of prefix 1 for specific types of calls and for specific subscribers. Local, toll, and interLATA call types can each be independently provisioned in the subscriber-profile table as follows:
•
•
•
For service access code (SAC) calls such as 500, 700, 800, and 900, the user must dial the prefix 1. The flags LOCAL-PFX1-OPT, INTERLATA-PFX1-OPT, and TOLL-PFX1-OPT in the Subscriber table do not affect these types of calls.
For a list of the specific provisioning parameters, see the Subscriber Profile table in the Cisco BTS 10200 Softswitch CLI Database. For a complete list of release cause codes, see the appendix of the Provisioning Guide.
Directory Services (411, 555-1212, and 0+ Listing Services)
The BTS 10200 supports the directory services access feature as specified in Telcordia document GR-532-CORE, LSSGR: Interface To Directory Assistance System (FSD 30-17-0000).
Directory services allows a subscriber to obtain the listed telephone number for a given name and address. The caller dials a specific service number to reach directory services, also referred to as directory assistance (DA). When a subscriber dials one of the following digit patterns, the BTS 10200 routes the call to the applicable directory services in the PSTN:
•
•
•
•
•
The service to the caller can be provided manually by a live operator, automated by a voice or dual tone multifrequency (DTMF) recognition system, or by a combination of these. The volume level from an automated voice-response unit, however, should be comparable to that of a live operator. Different network operators can employ different systems in providing directory services.
A typical directory services request requires that the caller first give the name of the town and city. The caller then provides the name of the person or business that the caller wants to call, including the spelling of unusual names. Finally, the caller states if the request is for residence or business. Additional services include handling multiple requests made during the same call and automatic connection to the person (or business) the caller wants to call.
Easily Recognizable Codes
The BTS 10200 supports selected easily recognizable codes (ERCs), as described in document SR-2275, Telcordia Notes on the Network, Section 3.3. The supported ERCs are:
•
•
•
•
Other Telcordia reference documents include:
•
•
Information Service Calls (900 and 976)
Information service calls (ISCs) provide a variety of announcement-related services on a national or local basis. There are two general categories of this service:
•
•
National calls are dialed as 1-900-xxx-xxxx and local calls are dialed as NPA-976-xxxx.
n11 support (211, 311, 411, 511, 611, 711, 811)
Note
This section describes BTS 10200 support for n11 services. The typical relationship between the n11 codes and the nature of dial (NOD) values is as follows.
For a complete list of NOD values, see the Nature of Dial command in the Cisco BTS 10200 Softswitch CLI Database. To view the current NOD values provisioned on your system, use the show nod CLI command.
For additional information on n11 calling, see the following industry documents:
•
•
Community Information and Referral Services (211)
The 211 service provides access to information from government service agencies and certain public charity groups.
Nonemergency Services (311)
Some city governments offer 311 service to provide nonemergency information to the community. The caller dials 311 and the Call Agent translates this to the closest nonemergency access office.
The BTS 10200 supports nonemergency services (311) for routing calls to a specified route type and identification. Routes for all nonemergencies (311) are allocated through the destination table by defining the call type (call-type=NON-EMG) and the routing information for the dialed digits.
Directory Assistance (411)
The 411 service provides directory assistance. See the "Directory Services (411, 555-1212, and 0+ Listing Services)" section.
Traffic and Transportation Information (511)
The 511 service provides access to information about local traffic conditions.
Repair Service (611)
The 611 service connects to the local telephone repair service (if the service provider offers this service).
Telecommunications Relay Services (711)
The 711 service provides access to telecommunications relay services (TRS).
Local Billing Services (811)
The 811 service connects to the local telephone billing office.
NRUF Reporting for NANPA Audit Support
Numbering Resource Utilization and Forecast (NRUF) reporting provides NANPA audit data based on provisioned values in the dn2subscriber table. For FCC-required NANPA audit compliance, the report input is NPANXX. In markets outside of NANPA, the input can be based on either the combination of the NDC and the EC, or just the EC.
The data for NRUF reporting is generated based on either the NDC or the EC. The service provider can use the report dn-summary command to generate the following reports:
•
•
Emergency Services (911)
The BTS 10200 supports emergency services (911) as specified in Telcordia document GR-529-CORE, LSSGR: Basic 911 Emergency Service (FSD 15-01-0000).
Other Telcordia reference documents include
•
•
Note
This section covers the following topics:
•
•
•
•
•
•
Description
The digit string 911 is typically used in the United States. Other digit strings are used elsewhere in the world.
Emergency service is a public safety feature providing emergency call routing to a designated Emergency Service Bureau (ESB), normally called the public safety answering point (PSAP) in the United States. The 3-digit 911 number is assigned for public use in many areas of the United States and Canada for reporting an emergency and requesting emergency assistance. Depending on municipal requirements and procedures, an ESB attendant can transfer the call to the proper agency, collect and relay emergency information to the agency, or dispatch emergency aid directly for one or more participating agencies.
911 calls are location dependent and must be selectively routed to the appropriate PSAP depending on where the call originates. The routing process is part of the Enhanced 911 (E911) feature set and works as follows:
1.
2.
Once the caller is connected to the PSAP attendant, the PSAP system typically displays the caller's directory number to the PSAP attendant. Additional data (such as the subscriber's name, address and closest emergency response units) may also be retrieved from the local carrier automatic location identification (ALI) database and displayed to the PSAP attendant.
The service provider can provision a flag for each subscriber to specify which number to send with emergency calls—the subscriber directory number or the subscriber billing number.
Special emergency functions can be provided via a channel-associated signaling (CAS) trunking gateway (TGW) that supports ESB trunks or emergency service line (ESL) trunks with MF signaling. Examples of special emergency functions include:
•
•
•
For additional details on these functions see the "911 Ring Back" section.
Important Provisioning Requirements
Service providers in the United States typically provision the Destination table with call-type=EMG for the digit string 911, and call-subtype=NONE (default), because 911 is a central dispatch point for all emergency, ambulance, fire, and police calls.
Caution
Depending on the region of the world, the provisionable timers might require different values, or might not be needed, and they can be turned off. The called-party control feature, typically used in the United States, can also be turned off. All other functions of the emergency number are the same as for the 911 feature.
You can make the emergency service feature available to all subscriber lines connected to a BTS 10200 by means of the default office service ID, or to all subscribers in a specific POP by means of the office service ID. See the "Office Service ID and Default Office Service ID" section on page 3-134 for a general description of this provisionable service.
Feature Interactions
The following feature interactions apply to emergency calls (call-type=EMG):
•
•
–
–
–
911 Overflow Announcement
The system plays an announcement when all circuits to the emergency center are busy and the emergency call cannot be completed to the emergency center. An example of an announcement for this feature is, "We are experiencing 911 difficulties. Please hang up and dial 0 to reach an operator for emergency assistance." The announcement is applied when the announcement resource is available and applicable. For the specific cause code and announcement ID, see the "Release Cause Codes and Announcement IDs" section in the Provisioning Guide.
Emergency 911 Trunk Connection Loss Alarm
The BTS 10200 is capable of generating a critical alarm of when an emergency trunk resource becomes remotely or locally blocked. This alarm will be raised when any of the following events occurs:
•
•
•
This feature is applicable only to emergency trunks of type CAS, SS7 and ISDN. The EMERGENCY-TRUNK-GROUP token in the applicable trunk group table must be provisioned to support this feature. For CAS trunk groups, the E911 / EMERGENCY-TRUNK token must also be provisioned.
Emergency Call Display
You can display of the number of currently active emergency calls with the query call-count command. In this command, you specify the call type that you want included in the count: emergency, police, ambulance, fire, all-emergency, or all. The system counts all calls regardless of whether it is an answered call or in the setup phase (transient or active).
The system display works as follows:
•
•
•
•
•
If the system is in an overload condition, it blocks the query call-count command.
Emergency Callback
The emergency callback (ECB) feature allows a public safety answering point (PSAP) operator to call back a BTS 10200 subscriber. The BTS 10200 treats these callbacks as special high-priority calls, and all terminating features that could potentially interrupt a call from a PSAP operator are disabled.
When the subscriber with ECB receives a call, the BTS 10200 checks the calling DN against the list of DNs in the emergency number list to determine whether it is coming from a PSAP. If the DN is in the list, the call receives ECB treatment.
ECB is an office-based feature; the system can provide ECB treatment to any subscriber associated with an office service that is provisioned with ECB.
ECB Interactions with Call Waiting
The ECB feature supports CW only if the calling party is the PSAP line. However, if the subscriber is already in an ECB call, you cannot invoke CW. The following table describes the interaction between ECB and CW.
ECB Interactions with Other Terminating Features
The following table describes the interaction between ECB and other features.
Anonymous Call Rejection
A PSAP call is always accepted by the ECB subscriber even if the caller is anonymous. If the calling party is not visible to the BTS 10200, the call is not classified as ECB. If ACR is activated, the call is rejected.
Automatic Recall
The ECB subscriber cannot invoke the automatic recall feature to a PSAP line.
Busy Line Verification
If the ECB subscriber is already engaged in an ECB call, the subscriber will not receive an interrupt and the PST is played back.
CALEA
CALEA is supported for ECB exactly as it is with normal calls.
Call Forwarding Busy
If the ECB subscriber is busy with a call, the PSAP caller hears a busy tone but the call is not forwarded.
Call Forwarding No Answer
If the subscriber does not pick up the call, it is not forwarded to the forwarding DN. The CFNA timer is not started and the phone will continue to ring.
Call Forwarding Unconditional
The subscriber receives the PSAP call even if CFU is activated.
Call Hold/Call Park/Call Transfer/Three Way
These services are inhibited during a PSAP call.
Calling Number Delivery/Calling Name Delivery
The PSAP calling name and number are not displayed to the subscriber.
Call Waiting
Refer to the "ECB Interactions with Call Waiting" section for a description of ECB interaction with CW.
Do Not Disturb
The subscriber receives PSAP calls even if DND is activated.
Directed Call Pickup
No other subscribers can pick up PSAP calls.
Distinctive Ringing
Distinctive ringing is not available.
Multi-Line Hunt Group
There is no special handling for MLHG. MLHG behaves the same for ECB and non-ECB calls.
Seasonal Suspend
The subscriber can receive calls with the seasonal suspend feature.
Selective Call Acceptance
The PSAP call is not checked against the SCA list, so the call is not blocked.
Selective Call Rejection
The PSAP call is not checked against the SCR list, so the call is not blocked.
Temporary Disconnect
Temporary disconnect subscribers do not receive ECB calls.
911 Ring Back
911 ring back describes a scenario wherein a Public Safety Answering Point (PSAP) operator is communicating with someone who has dialed 911 and the caller hangs up before the PSAP operator has all of the information that the operator needs. The operator commands the terminating switch to ring back the caller.
Note
When the caller and the PSAP are both on the same BTS 10200, the BTS 10200 retains the call and connection if the B911 caller hangs up. If the caller and the PSAP are on separate BTS 10200 nodes, the connection between the two BTS 10200 nodes is maintained over a SIP trunk.
Sequence of Events for 911 Ring Back
The example shown in Figure 1-1 is a typical sequence of events for the 911 ring back over SIP trunk. In this example, there is a cable subscriber that dials 911 and the call is connected to a PSAP operator. After the connection is established, the cable subscriber hangs up before the operator has gathered all of the necessary information. Upon request from the operator, the BTS 10200 rings back the cable subscriber's phone so that the conversation with the PSAP operator can continue. Figure 1-1 illustrates the following sequence of events:
1.
2.
3.
4.
5.
6.
7.
8.
Figure 1-1 Network Diagram for B911 Operator Ring Back
Note
SIP Trunk Provisioning
The SIP trunk between the two BTS 10200 nodes is provisioned through the softsw-tg-profile table. When you provision the 911 feature, you must provision this table for any SIP trunks between the BTS 10200 nodes. The ENABLE_P_DCS_OSPS_HEADER token in this table has a default value of N; you must set it to Y for this SIP trunk. When this token is set to Y and an OSPS-related request is made, the BTS 10200 includes a P-DCS OSPS header in the outgoing INVITE or UPDATE messages as defined in RFC-3603. If this token is set to N, the system does not send outgoing SIP requests or accept incoming SIP requests that are OSPS related.
Feature Provisioning Commands
To provision this feature, see the 911 provisioning procedure in the Provisioning Guide.
Operator Services
The BTS 10200 supports the operator services specified in Telcordia Requirement FR-271, Operator Services Systems Generic Requirements (OSSGR).
Operator services is a call-processing function that enables callers to access either a live operator or an automated function to complete calls or gain access to information. The service provider can supply this feature or outsource it to a third-party vendor. Some additional functions accomplished by operator services include automatic call distribution, billing detail recording, and information retrieval.
This section includes the following additional topics:
•
•
Numbers Used to Access Operator Services
The following numbers are commonly used to access operator services:
•
•
•
•
•
•
Types of Services
Operator services provided to callers typically include:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Busy Line Verification (BLV) and Operator Interrupt (OI) Services
This section describes busy line verification (BLV) and operator interrupt (OI) services. OI is also referred to as emergency interrupt (EI). BLV and OI services are based on GR-1176 (FSD 80-01-0300), Busy Line Verification, part of Telcordia OSSGR requirements (FR-271).
Description and Operation
BLV service permits the user to obtain operator assistance to determine if a called line is in use. The user dials 0, waits for the operator to pick up the line, and requests BLV service. OI service permits the operator to speak directly with the busy party. The service provider can deny BLV service to any subscriber by setting type=denied for fname=BLV in the subscriber-feature-data table (see the BLV provisioning link listed below). Note that denying BLV also denies OI.
BLV and OI services work as follows:
1.
2.
3.
4.
5.
Note
The BLV feature can be made available to all subscriber lines connected to a BTS 10200 by use of the default office service ID, or to all subscribers in a specific POP using the office service ID. See the "Office Service ID and Default Office Service ID" section on page 3-134 for a general description of this provisionable service.
Feature Interactions
The following feature interactions are applicable to the BLV and OI services:
•
•
BLV/OI over SIP Trunk between BTS 10200 Nodes
When the caller and the operator service position system (OSPS) are on separate BTS 10200 nodes, the connection between the two BTS 10200 nodes is provided by a SIP trunk.
Figure 1-2 shows a typical sequence of events that occur for BLV/OI over the SIP trunk. The sequence deals with the case in which a busy party is involved.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
In Figure 1-2, the customer and 3rd party are shown to be in the PSTN (SS7) network, but they could be elsewhere.
Figure 1-2 Network Diagram for BLV/OI
The SIP trunk between the two BTS 10200 nodes is provisioned through the softsw-tg-profile table. When you provision the BLV feature, you must provision this table for any SIP trunks between the BTS 10200 nodes. The ENABLE_P_DCS_OSPS_HEADER token in this table has a default value of N; you must set it to Y for this SIP trunk. When this token is set to Y and an OSPS-related request is made, the BTS 10200 includes a P-DCS OSPS header in the outgoing INVITE or UPDATE messages as defined in RFC-3603. If this token is set to N, the system does not send outgoing SIP requests or accept incoming SIP requests that are OSPS related.
Feature Provisioning Commands
To provision this feature, see the BLV provisioning procedure in the Provisioning Guide.
SIP Triggers
This section describes the SIP triggers feature. Also refer to the "BTS 10200 CALEA Interaction with SIP Triggers Feature" section on page 2-10.
Feature Limitation
SIP triggers are not supported for Centrex subscribers.
Technical Description of SIP Triggers
The SIP Triggers feature uses the SIP protocol, with some extensions, to enable the BTS 10200 to interoperate with third-party application servers so that Multi-Service Operators (MSOs) can provide customers with enhanced features and services. The triggers can be used by the third-party servers to provide originating services (such as voice dial) when a subscriber places a call, and enhanced terminating services (such as TV caller ID and custom ringback) when a subscriber receives a call. This section describes the triggers that enable this interoperation with the third-party application servers.
The BTS 10200 supports multiple application servers. Application servers are provisioned per subscriber origination and subscriber termination. You can provision SIP triggers on an individual subscriber level on the BTS 10200.
From the perspective of the BTS 10200, a SIP subscriber appears as a SIP user agent (UA); this is true whether the subscriber's device is a SIP eMTA, ATA, or PAP2. At the customer premises, the subscriber's device performs the role of the UA, and might perform other operational functions as well.
Figure 1-3 shows a typical network architecture for SIP triggers, including the connection between the BTS 10200 and the third-party application server.
Figure 1-3 Typical Network Architecture for SIP Triggers
Acronyms for Figure 1-3CALEA—Communications Assistance for Law Enforcement Act
NCS—Network-based call signaling
SBC—Session border controller
CMTS—Cable modem termination system
IVR—Interactive voice response
Terminology Used in this Section
The following terminology is used in this section:
•
•
–
–
Off-Hook Trigger (Delayed and Immediate)
The BTS 10200 responds to the OHD trigger differently for MGCP/NCS subscribers than for SIP subscribers.
There is an OHD trigger provisioned as fname=OHD in the Feature table, and there is a delayed or immediate designation provisioned as offhook-trigger-type=OHD or OHI in the Subscriber table. The ohd_timer parameter is also provisioned in the Subscriber table.
Note
OHD Treatment for MGCP/NCS Subscribers
The OHD trigger occurs either immediately after the user goes off-hook (if offhook-trigger-type in the Subscriber table is set to OHI) or after a delay set through a configurable timer (if offhook-trigger-type=OHD).
•
•
OHD Treatment for SIP Subscribers
When the BTS 10200 receives an INVITE message from the SIP subscriber (that is, from the UA), it takes actions based on the content of the incoming INVITE and the parameters provisioned in the BTS 10200 database.
This section contains the following topics:
•
•
OHD Associated with a Vertical Service Code
You can associate the OHD feature with a specific vertical service code (VSC), for example fname=OHD and digit_string=*40. In this case, if the BTS 10200 receives ad INVITE from the UA, it takes the following action:
•
INVITE(*40) ->BTS 10200-> INVITE( )INVITE(*40 + 10DIGITS) ->BTS 10200-> INVITE( )•
OHD Assigned to the Subscriber
You can assign the OHD feature to a subscriber, and designate the value of the offhook_trigger_type (in the Subscriber table) as OHD or OHI. In this case, when the BTS 10200 receives an INVITE from the UA, it takes the following action:
•
INVITE(*92 + 10DIGITS) ->BTS 10200-> INVITE( )INVITE(*40 + 10DIGITS) ->BTS 10200-> INVITE( )•
INVITE(*92 + 10DIGITS) ->BTS 10200-> INVITE(*92 + 10DIGITS)INVITE(*40 + 10DIGITS) ->BTS 10200-> INVITE(*40 + 10DIGITS)•
–
–
INVITE(911) ->BTS 10200-> INVITE(911)INVITE(110) ->BTS 10200-> INVITE(110)–
–
INVITE(3925550123) ->BTS 10200-> INVITE(3925550123)When the SIP trigger is not sent successfully to the application server due to a sever or network connectivity problem due to any problem, the BTS 10200 connects the call to an IVR server to enable digit collection and call completion. However, if the IVR connection is unsuccessful, the call fails.
OHD Call Flow Diagrams
The diagrams in this section show examples of OHD call flows for SIP subscribers
The OHI scenario is shown in Figure 1-4.
Figure 1-4 Offhook_trigger_type set to OHI
The OHD scenario is shown in Figure 1-5.
Figure 1-5 Offhook_trigger_type set to OHD
The usage-sensitive scenario is shown in Figure 1-6.
Figure 1-6 Usage-Sensitive OHD Scenario
