> For the complete documentation index, see [llms.txt](https://ss7-attacks.telco-sec.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ss7-attacks.telco-sec.com/location-disclosure/ati-any-time-interrogation.md).

# ATI - Any Time Interrogation

**Anythime Interrogation (ATI)** is a procedure in the SS7 Mobile Application Part (MAP) protocol that allows a network entity to request information about a subscriber from the Home Location Register (HLR) or Home Subscriber Server (HSS) at any time. 

This information can include subscriber location or other live data and plays a crucial role in delivering services like location-based services, fraud detection, and lawful interception. 

<figure><img src="/files/ZCp6TITouxjypRfgtfsY" alt=""><figcaption></figcaption></figure>

The ATI operation is initiated by sending an ATI Invoke message to the HLR/HSS, which then processes the request and returns the desired subscriber information.

#### Process of Any Time Interrogation

1. **Request Initiation**: A network entity such as a Mobile Switching Center (MSC) or a Service Control Point (SCP) initiates an ATI request to the HLR/HSS.
2. **ATI Invoke Message**: This request is sent as an ATI Invoke message containing subscriber identifiers, which can include IMSI or MSISDN.
3. **Processing by HLR/HSS**: On receiving the ATI Invoke message, the HLR/HSS processes it to retrieve the requested subscriber information.
4. **Response**: The HLR/HSS sends a response back to the requesting network entity with the requested data.

#### Use Cases

* **Location-Based Services (LBS)**: Provides real-time location information, enabling services like navigation, tracking, and location-based advertising.
* **Fraud Detection**: Monitors location and usage patterns to identify and prevent fraudulent activities, ensuring secure subscriber transactions.
* **Lawful Interception**: Assists law enforcement agencies by providing information necessary for legal surveillance and data collection.

#### Security Considerations

Ensuring that ATI requests are only executed by authorized entities is critical to protect subscriber privacy and data integrity.&#x20;

Authentication and encryption mechanisms should be implemented to safeguard sensitive information throughout the process.

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### ATSI Request

```

AnyTimeSubscriptionInterrogationArg ::= SEQUENCE {  
subscriberIdentity [0] SubscriberIdentity,  
requestedSubscriptionInfo [1] RequestedSubscriptionInfo,  
gsmSCF-Address [2] ISDN-AddressString,  
extensionContainer [3] ExtensionContainer OPTIONAL,  
longFTN-Supported [4] NULL OPTIONAL,  
...} 
```