Summary

Voice and voice-band data traffic in international networks has traditionally been transported by circuit switched systems and equipment. On the other hand, IP network technology has advanced rapidly, and high-speed networks utilizing the IP transport technique have been constructed worldwide with a view to support increasing future demand of multimedia communications. In parallel with this trend, low-rate voice coding technology hasfurther progressed recently and, by using the technology, a system of transporting voice, facsimile voice-band data traffic over the IP‑based networks has been developed and is now available in the market as VoIP (Voice over IP) systems.

By reviewing the technologies used for the VoIP system and comparing them with those used for Circuit Multiplication Equipment (CME)'s, one can recognize that the IP-based voice transmission technique can be applied to realize a new type of CME, namely a CME optimised for IP-based networks (IP-CME). Thus it can be expected that this new type of CME certainly contributes to construct future cost-effective voice, facsimile and voice-band signals transmission networks in the next generation global information infrastructure.

This Recommendation contains principles and examples of multiplication schemes of voice and voice-band data between the International Switching Centre (ISC) (exchanges) which are connected via IP-based networks.