Question: What is the data type of the Filter-Id Attribute Value Pair (AVP) in ProSe function signalling, as per 3GPP specifications?
Option 1: UTF8String
Option 2: OctetString
Option 3: Integer32
Option 4: Unsigned32
Explanation: In the context of ProSe (Proximity Services) function signalling, specifically for attribute value pairs related to discovery filters, the Filter-Id AVP is defined as being of type OctetString. This means it can contain a sequence of octets (8-bit bytes), which is suitable for representing identifiers in a flexible and efficient manner, allowing for various encoding schemes if necessary. This data type choice supports the broad applicability of Filter-Id across different discovery scenarios in telecom networks.