Voice Over IP

SUMMARY

Data networks in general, and the Internet in particular, are designed to support asynchronous, non-real-time traffic. The variable delay in data networks is usually not a big problem, due to the asynchronous nature of data applications.

The design philosophy of data networks is the opposite of voice networks. Voice networks are designed to support synchronous real-time traffic, with a fixed delay between the sender and the receiver.

Three obstacles must be overcome if the Internet and internets are to be effective bearers of speech: (a) latency must be reduced, (b) jitter must be reduced, (b) traffic loss must be improved.

UDP and IP are the chosen L_4 and L_3 protocols for VoIP. Their choice has nothing to do with their merit (although ...