What is the role of this network element {Bootstrapping server function (BSF) } in LTE ?

Question

I looked at DIAMETER interfaces and went on Dz interface. It is an interface between BSF and SLF. For SLF i was aware of like Subscriber Location Function but BSF i didn't even have a hint.
is here anyone who can explain this?

Answer 1

The BSF queries SLF over Dz as you mentioned to get the name of the HSS containing the required subscriber specific data.

It's similar to Zh or Zh' (Z-h-prim) interface used by BSF to connect to HLR to fetch authentication information.

Check the 3GPP 33.220 for more details
http://www.3gpp.org/ftp/specs/archive/33_series/33.220/

Answer 2

BSF is hosted in a network element under the control of an Mobile Network Operator (MNO).

BSF, HSS and UE participate in Generic Bootstraping Architecture (GBA) in which a shared secret is established between the network and a UE by running the bootstrapping procedure. The shared secret can be used between Network Application Functions (NAF's) and UE's,
E.g. : For authentication purposes

For Specification TS 33.220