scope:

The present document considers the following aspects of IP address retention and traceability:

1) Basic Internet Protocol principles, highlighting specifically how IP addresses and ports are used to access the internet.

2) Key differences between IPv4, IPv6, Dual Stack and other relevant layer 3 protocols.

3) How IP addresses are allocated within networks, including EPC and 5GC, documenting any differences in approach.

4) The role of Network and Port address translation within a CSP network.

5) The impact address translation technologies on IP address attribution as observed from outside the CSP network. This includes a discussion on the different translation technologies commonly used by CSPs (e.g. NAT, PAT, CGNAT, NAT64).

6) Description of the key elements which define user and IP address association and therefore make up the minimal set of stored attributes for a viable IP retention solution.

7) Methods for accessing records of IP and port allocation from within a CSP network.

8) Methods for retaining and querying stored IP association records; consideration is given to the storage volumes, durations and accuracy.

The present document does not consider TOR^®, VPN services or over top identity protection services, which may impact the ability to attribute observed IP addresses to a specific User Equipment.