Overview

A call detail record (CDR) contains a lot of useful information about a call which allows users to identify potential problem areas or scenarios. However the information contained in the CDR is often insufficient to determine the root cause of the issue.

There is significantly more information contained in the signalling events for the call as these signalling events record every single aspect and detail of the call and thus can be used to determine exactly what transpired at every stage of the call.

The signalling events occur between every network element involved in the setup, carrying, management and termination of the call and a separate signalling dialogue is set up between each corresponding network element. These signalling messages occur individually across all layers of the signalling network.

These separate signalling dialogues for the same call, coupled with the excessive volume of signalling events (on average well over 200 signalling events for 1 voice call) and the highly specialised nature underlying signalling makes it extremely difficult to correlate the signalling with the CDR on a large scale.

Therefore in most cases, revenue assurance never uses signalling events to perform root cause analysis. Even the engineering department only use them sparingly, and then normally filter on specifically expected signals so as to decrease the volume of signalling recorded and analysed. Thus assumptions need to be made, and sampling implemented, and thus not all scenarios may be captured.

Solution

iServ allows the user to load all the signalling events for the period under review into the system. The signalling events can be loaded from any source including a test instrument, software trace directly off the network element (MSC, IN, etc.) or network signalling probe, etc. These signalling events can be from a few minutes or hours to any longer period required including on a continuous basis.
This SS7 Event Correlation application automatically correlates all the signalling events associated with a specific CDR. All the signalling events for each CDR are grouped together in time and invoke order so the entire detailed call flow and interaction between each network element can be viewed. The output is displayed in both diagrammatical format, showing the order of signalling between all involved network elements, and detailed format containing all fields and information for each signalling event.

Most revenue assurance issues and / or customer complaints are first highlighted by and investigated against a CDR. When the information contained in the CDR proves inadequate to determine the exact cause of the issue, these CDRs can easily be matched to the signalling events associated with this CDR using iServ SS7 Event Correlation. .

Any number of CDRs can be matched to their underlying signalling events at the same time. I.e. A query can be run against the CDRs isolating the problematic CDRs. The signalling events for all these CDRs can then be automatically extracted at the same time by iServ SS7 Event Correlation.

This application is an extremely useful and important tool for revenue assurance as well as network maintenance staff.