Stand-Alone User Processing Node Traffic Monitoring

In Stand-alone User Processing Node (UPN) traffic monitoring, the UPN processes the subscriber information that is extracted from the PFCP packets and correlates with the GTP-u traffic without the CPN. When the traffic contains the User's field information such as IMSI, IMEI, you can use the Stand-Alone User Processing Node traffic monitoring.

PFCP (Packet Forwarding Control Protocol) is a 3GPP Protocol that is communicated on the Sx/N4 Interface between the Control Plane (CP) elements and User Plane (UP) elements. The CP element programs the UP element with policies on how to forward packets. PFCP packets convey information in the form of Information Elements (IE). PFCP allows an optional IE called User Fields that contains IMSI/SUPI, IMEI/PEI, MSISDN/GPSI information of the Subscriber during PFCP Session Establishment Request.

The UPN performs the following activities in the Stand-alone mode:

  • Processes the PFCP session establishment request and extracts the IMSI, User IP and TEID for both end points. The information in the PFCP traffic is used to populate the UPN's session table.
  • Creates a GTP control tunnel based on the subscriber information and corresponding user tunnel. GTP-U look up is correlated based on the IP TEID .

The following diagrams explain the functioning of UPN in Stand-alone mode:

 

 

 

  • A Stand-alone UPN traffic monitoring session can be created only when there is atleast SUPI in the user fields.
  • You cannot perform RAN correlation or Network Slicing Correlation in Stand alone UPN traffic monitoring
  • UPN does not receive SFFP messages in the User field parse mode.

The following are the points to remember while configuring Stand-Alone User Processing Node:

  • You must enable the stand-alone mode in UPN while creating the solution in Ansible.
  • Once the stand-alone mode is enabled, UPN cannot connect with the CPN, and you cannot the change the mode. To change the mode, you need to delete the UPN from the solution and add a new one.