4.3 Trace Overview
A trace is a set of conditions which, when met, causes trace data to be forwarded to IDIH for further analysis.
DSR determines which message should be captured based on trace criteria created and activated. The trace criteria identifies the following scope and content:
- Scope refers to the non protocol related elements such as connections or peers, used to select messages to evaluate trace content.
- Content refers to the protocol related elements such as command codes and AVPs, used to refine the trace criteria.
As DSR processes request and response messages, they are analyzed for matching any of the active trace definitions. If a match is found, message components along with supplemental information, known as trace data is transferred to the IDIH. The IDIH assembles the trace data and provides it to the user leveraging graphical visualization interfaces for additional filtering and analysis.
Figure 4-1 IDIH trace cycle
The above call flow shows IDIH trace cycle (ProTrace visualization). The LIR (Request) is routed to the local node, which then forwards the LIR to the HSS after mapping with various parameters, and finally the LIR reaches the HSS, which answers to the LIR. Here is an illustration (LIA is the response) that will be forwarded to MME.