Abstract

We address the well-known issue of one-way RTP flows in VoIP communications. We investigate the main causes that usually lead to this type of fault, and we propose a methodology allowing for their automated online detection and diagnosis. The envisaged approach exploits node cooperation and is based on a more general framework for network faults diagnosis called DYSWIS (Do You See What I See). As most of the problems associated with one-way RTP can be ascribed to the presence of NAT elements along the communication path, one of the key features of the proposed methodology resides in the capability to detect such type of devices. Besides, another important aspect of this work is that the diagnosis is non-intrusive, meaning that the whole process is based on the passive observation of flowing packets, and on silent active probing that is transparent to the users. In this way, we also avoid the possibility of being classified as SPIT (SPam over Internet Telephony). We provide a thorough description of the various steps the diagnosing process goes through, together with some implementation details as well as the results of the validation process. 1.

Citations