1

Are the 5G control plane reference point interfaces (e.g. N11) just used for display purposes, or are they actually separate interfaces used in signaling? Stated another way, when the AMF is communicating with the SMF, do some messages go through the SBI and other messages go through S11?

I was under the impression that 3GPP requires all the 5G control plane interfaces to only use the service based interfaces. If this is true, why does N11 even exist, other than for a reference point of confusion :-).

Karthik Balaguru
  • 7,424
  • 7
  • 48
  • 65
Alan
  • 19
  • 1

1 Answers1

1

The interaction between NF (network functions) are represented in two ways as the 5G architecture is defined as service-based and reference point based. N11 reference point is a representation here for the interface between AMF and SMF. It is for bringing in identification for the interface between the NF services of respective network functions for the messages that are exchanged over respective SBI.

The NFs within the 5GC Control Plane shall only use SBI for their interactions.

A typical Control Plane NF can provide one or more NF Services and the NF Service consist of operations based on either a request-response or a subscribe-notify model and it uses Common control protocol like HTTP based API, replacing protocols like Diameter.

AMF and SMF are typically NFs that shall be running in virtual machines or bare metal as per MNO preference. Within the 5GC, the AMF offers services to the SMF. The AMF uses the Namf service based interface(SBI) and offers services to the SMF, other AMF, PCF, SMSF, LMF, GMLC, CBCF, PWS-IWF and NEF.

Karthik Balaguru
  • 7,424
  • 7
  • 48
  • 65