At its foundation and as the title would suggest, event correlation is a tool that is used by IT managers across the globe to track, analyze and report on various events spanning across their network from applications, routers and other devices. The massive volume of these events happening minute to minute on your network is just too much for a human being to keep track of, and an event correlation tool looks for patterns from pre-set rules that trigger alerts for the IT department to look into. In today’s piece, we take a look at the various event correlation techniques that IT professionals successfully use.

In all of the event correlation techniques we will touch on today, there are a few common themes that will remain true throughout. First and foremost, they all are based on finding and notifying the user of potentially harmful events. Secondly, they are all themed with finding the actual cause of the issue you are facing. And as the name would suggest, all of the following event correlation techniques correlate events to single them out and prepare you and your team for action moving forward surrounding the events in question.

Widely considered one of the most successful event correlation techniques is a technique called rule-based reasoning. Rule based reasoning at its core uses what is referred to as a knowledge base to create a chain reaction type of rule that says if something happens, do this. Rules within the rule based reasoning are how the system knows which operational actions that need to be carried out. The technique also uses what is called a working memory that learns and will ultimately realize for you when your network goes into a dangerous mode. Within it, it logs information about the networking being analyzed and can provide real-time feedback to you and your team. In conjunction with the knowledge base, an interference engine takes a look at the current status of on the rule-base and ties it to a similar output within the rule. Once this takes places, the knowledge base puts an action into effect in real-time using the working memory to do so. One thing to note and keep in mind if you decide to move forward with this approach, is that as the working memory is more fully utilized, the needs for the associated memory grows quickly.

Another one of the more popular event correlation techniques is a technique referred to as the codebook approach. In the codebook approach, a causality graph model identifies the fundamental relationship between problems and the associated symptoms and creates a unique code that can be tied to the problem. With this, you can quickly identify known issues by referring to the matching code giving you and your team the chance to act on it as fast as possible. The algorithm itself is code-based by nature, and can easily recognize potentially dangerous event correlations.
In summary, there is no full proof completely perfect event correlation technique. The thing to remember when thinking about event correlation techniques is to choose one that your team can implement efficiently and that does not cause a disruption in the effective use of your event correlation tool itself. Also, when researching and ultimately deciding on an event correlation technique, it’s not required to only choose one. A hybrid approach of multiple event correlation techniques is common and when done correctly can be quite effective in solving problems and successfully conducting your root cause analysis. Combining rule based reasoning with another approach called case based reasoning, is one example of a hybrid type approach that can pay dividends.