A network monitoring system that summarizes a plurality of data packets of a session into a compact session record for storage and processing. Each session record may be produced in real-time and made available during the session and/or after the termination of the session. Depending on protocols, a network monitoring system extracts different sets of information, removes redundant information from the plurality of data packets, and adds performance information to produce the session record. The network monitoring system may retrieve and process a single session record or multiple session records for the same or different protocols to determine cause of events, resolve issues in a network or evaluate network performance or conditions. The session record enables analysis in the units of session instead of individual packets. Hence, the network monitoring system can analyze events, issues or performance of the network more efficiently and effectively.