Inferring candidates that are potentially responsible for user-perceptible network problems

A method comprising:

• monitoring a network in which a response to a service request is selected from a group of responses comprising:
• a non response, an incorrect response, an untimely correct response, and a timely correct response, the non-response, the incorrect response, and the untimely correct response each considered a user-perceptible network problem;
• and
• using an inference graph to produce a list of candidates that are potentially responsible for user-perceptible network problems, the candidates comprising network components including services and network elements, the inference graph including:
• root-cause nodes that correspond to hardware components or services whose failure or degradation can cause the user-perceptible network problems;
• and
• observation nodes that represent at least accesses to the services of the network.

A method comprising:

• ascertaining multiple assignment vectors for candidate states of root-cause nodes of an inference graph, the inference graph reflecting cross-layer components including services and hardware components of a network, the root-cause nodes corresponding to the hardware components or the services whose failure or degradation can cause user-perceptible network problems;
• determining probability distributions for observation nodes of the inference graph for each of the multiple assignment vectors, each of the observation nodes corresponding to at least one measurable quantity of the network;
• calculating a respective score for each respective assignment vector based on respective ones of the probability distributions and responsive to observed values of the observation nodes;
• and
• selecting at least one candidate from the multiple assignment vectors for the candidate states for a list of candidates using the calculated scores, the list of candidates to include a determinable number of top candidates.