TSP Lab	Call Notification	Sga-CN

Sga-CallNotification
‘Who Called’ and ‘Notify Me’ services,
implemented by
AITIA Inc.

Introduction
System Overview
- Hardware components
- Software components
Installation
- Installation and wiring of the Sga-47 PCM interface card
- Configuration of the software
Summary

Introduction

Brief introduction of the WhoCalled service

If called subscribers are unreachable or busy for a period of time, they get information SMS about missed calls as soon as they become available.

Available features

Subscribers who were unreachable get one information SMS from one caller per session, irrespectively the number of calls. If A calls B more than one times - while B is not reachable continuously for a period of time - only one SMS will be sent (per each "A"), as soon as B becomes available.
Subscribers who were busy get the information SMS right away.
Number A is indicated as the sender of the SMS. Using the phone book function of the handset, identification of the calling party is possible for the called party.
SMS is not sent about a missed call started by caller who has CLIR, or has the CLI restricted for that particular call.
The "Who called" SMS can be configured to contain the time of the last call.
If the Operator indicates the reason of unsuccessfulness (e.g. busy, not reachable), it can also be included in the information SMS.

Brief introduction of the NotifyMe service

If called subscribers are unreachable for a period of time, the callers get information in SMS about unsuccessful calls as soon as the called parties become available.

Available features

One SMS from one called per session, irrespectively the number of calls. If A calls B more than one times - while B is not reachable continuously for a period of time - only one SMS will be sent (per each "A"), as soon as B becomes available.
Number B is indicated as the sender of the SMS. Using the phone book function of the handset, identification of the called party is possible for the calling party.

General features of the SGA-CN system

Sga-CN receives unsuccessful call triggers using ISUP, as well as SIP
Exception list for subscribers who do not want to receive information SMS (Black List feature)
The SGA-CN System generates log about
- the unsuccessful calls handled and
- the SMSs sent out.
The logging can be set at 4 levels from minimum information to detailed.
SGA-CN generates statistics about the traffic handled and forwards them to PMS/NOC if required.
Multilevel alarms can be generated.
Remote supervision is facilitated.

For the detailed behaviour, please click on one of the following links:

Handling of ISUP call triggers
Handling of SIP call triggers

How does SGA-CN work for ISUP triggers?

ISUP/IAM goes towards SgaCallNotification including:

A number as CallingPartyNumber (CagPN)
B number as OriginalCalledNumber (OriCN) / RedirectionNumber (RedGN)
Service number as CalledPartyNumber (CadPN)
Redirection Information

CASE A: RedirectionInformation = Busy(1)

Click to enlarge!

Sga-WhoCalled answers the ISUP/IAM with an ISUP/ACM and after
SgaWCx.ini/[SS7 Advanced]/dwChannelSeizedTimeOutSec time sends an ISUP/REL with release cause = Busy (17)
If CagPN presentation is
- allowed, a "WhoCalled" SMS will be sent to RedGN with CagPN as sender;
- not allowed, the "WhoCalled" SMS will not be sent.

CASE B: RedirectionInformation = NoReply(2)

Nota Bene: This case should not happen if the MSC is configured as expected.

The ISUP/IAM is answered with an ISUP/ACM and after dwChannelSeizedTimeOutSec time an ISUP/REL is sent with ReleaseCause=INI/[SS7 Advanced]/byISUPCongestionReleaseCause is sent on the given CIC
...and no SMS is sent out.

CASE "OTHER": RedirectionInformation = Other

Nota Bene: This is the actual "subscriber not reachable" case.

This case has three subcases.

Subcase 1

Click to enlarge!

The ISUP/IAM is answered with an ISUP/ACM and after dwChannelSeizedTimeOutSec time an ISUP/REL is sent with ReleaseCause=INI/[SS7 Advanced]/byISUPCongestionReleaseCause is sent.
If CagPN presentation is
- allowed:
  - Sga-WhoCalled sends an SRI4SM message to the HLR and the HLR answers the current MSC and the IMSI of the called subscriber.
  - Called and Calling party numbers and the timestamp inserted into the memory.
  - An invisible SMS is sent to the MSC/VLR of the called party. Since the subscriber is still unreachable the MSC/VLR answers "Absent subscriber".
  - Sga-WhoCalled asks the HLR to report if the status of enqued invisible SMS has changed (e.g. subscriber becomes available and it has been delivered) with a RepostSMDeliveryStatus.
  - When HLR informs Sga-WhoCalled that the subscriber has became available with an AlertSC message:
    - A "WhoCalled" SMS will be sent to RedGN with MSISDN_A as sender;
    - A "NotifyMe" SMS will be sent to MSISDN_A with RedGN as sender.
  - Related memory entry is purged.
- not allowed:
  - Neither "A" nor "B" will receive an SMS ("NotifyMe" and "WhoCalled", respectively)

Subcase 2

Click to enlarge!

The ISUP/IAM is answered with an ISUP/ACM and after dwChannelSeizedTimeOutSec time an ISUP/REL is sent with ReleaseCause=INI/[SS7 Advanced]/byISUPCongestionReleaseCause is sent..
If CagPN presentation is
- allowed:
  - Sga-WhoCalled sends an SRI4SM message to HLR but HLR answers the subscriber is "Absent".
  - Sga-WhoCalled asks the HLR to report if the status of the subscriber has changed (e.g. subscriber becomes available) with a RepostSMDeliveryStatus.
  - When HLR informs Sga-WhoCalled that the subscriber has became available with an AlertSC message:
    - A "WhoCalled" SMS will be sent to RedGN with MSISDN_A as sender;
    - A "NotifyMe" SMS will be sent to MSISDN_A with RedGN as sender.
  - Related memory entry is purged.
- not allowed:
  - Neither "A" nor "B" will receive an SMS ("NotifyMe" and "WhoCalled", respectively)

Subcase 3

Click to enlarge!

The ISUP/IAM is answered with an ISUP/ACM and after dwChannelSeizedTimeOutSec time an ISUP/REL is sent with ReleaseCause=INI/[SS7 Advanced]/byISUPCongestionReleaseCause is sent.
If CagPN presentation is
- allowed:
  - Sga-WhoCalled sends an SRI4SM message to the HLR and the HLR answers the current MSC and the IMSI of the called subscriber.
  - When the attemptig to send an invisible SMS is successful because the subscriber is available after all:
    - A "WhoCalled" SMS will be sent to RedGN with MSISDN_A as sender;
    - A "NotifyMe" SMS will be sent to MSISDN_A with RedGN as sender.
  - Related memory entry is purged.
- not allowed:
  - Neither "A" nor "B" will receive an SMS ("NotifyMe" and "WhoCalled", respectively)

How does SGA-CN work for SIP triggers?

SIP/INVITE goes towards SgaCallNotification including:

A number from the "From" header (calling party)
B number from the "Diversion" header (called party)
Service number from the "To" header
Diversion reason from the "Diversion" header

CASE A: Diversion reason = user-busy

Click to enlarge!

Sga-WhoCalled module answers the SIP/INVITE with a SIP/<status-code>; e.g.: "486 Busy Here" (status-code is configurable: SgaWCx.ini/[SIP Settings]/sInviteResponse_Busy).
If "A" (called party) number presentation is
- allowed, a "WhoCalled" SMS will be sent to called party number (Diversion) with calling party number (From) as sender;
- not allowed, callee will not get a "WhoCalled" SMS.