2 percent. There are pauses between sentences and They are Adaptive Clocking and Synchronous Residual words with no speech in either direction. Also, voice Time Stamping (SRTS). These mechanisms work by Table 3.2-2 Comparison between various compression algorithms. Algorithm Bandwidth MIPS (C5x DSP) Total Codec Delay (msec) Application 64 kbit/s ADPCM (G.726) 32 kbit/s PSTN, cordless phones CS-ACELP (G.729) 8 kbit/s VoFR, VoATM, VolP CS-ACELP Annex A (G.729A) 8 kbit/s VoFR, VoATM, VolP LD-CELP (G.728) 16 kbit/s MP-MLQ (G. 723.1) 5.3/6.3 kbit/s Multimedia and VolP CHAPTER 3.2 Network infrastructure adjusting the clock rate at one end of the circuit based on voice switching, the ATM switch receives a call and the clock rate of the other end. routes it to the appropriate destination. The VPN net- The above-mentioned mechanisms work effectively work fits appropriately for this kind of functionality. This only in the master-slave environment or point-to-point type of network solution requires that ATM networks communication. When multipoint services are in opera- interpret the signaling provided from the voice network. tion, it is not possible for a slave to adjust its clock based Previously, this posed a major challenge as the signaling on two or more difference signals coming from different standards were proprietary. At the present, many ven- master sites. For multipoint service, it is easy to adopt an dors provide ATM-based solutions that are able to in- externally synchronized model where each node in the terpret the signaling provided by their own voice network is synchronized to some external clock source. switches. Widespread adoption of ISDN and QSIG voice signaling standards are allowing ATM vendors to offer Standards and specifications of ATM a standardized voice signaling interface. From the foregoing analysis of various network oper- Various applications are available for the transport of ators and transport models, one could see a common set voice over an ATM network. Each application has dif- of network