Efficient Table Lookup Method for Performance Monitoring of VoIP Flows in Mobile Environment

Not only the fixed but also the mobile network operators emerge to face the challenge of performance monitoring. The performance monitoring for the high speed link (e.g., 10Gbit/s) requires the high speed table lookup for searching flow information from five tuples (IP addresses, protocol and port numbers) of a VoIP packet. Using a hash table and a content-addressable memory (CAM) can generally achieve the high speed table lookup by registering, to the CAM, entry keys of flows frequently arriving. However, this does not properly work for VoIP packets since VoIP flows have low and similar rates. We propose a novel method using the CAM which achieves the highspeed table lookup even for the VoIP flows. The evaluation reveals that the proposed method can obtain a high CAM hit ratio (90%), and indicates that the table lookup can have small capacity of the CAM (only 2% of the amount of registered calls).