ixed end points. This is an ap- end-to-end transport of voice signaling propriate mechanism for connecting of voice switch sites, (Common Channel or Channel Associated) with the voice traffic PBXs, or message switching centers. Here, network is not needed to process or terminate signaling, other than the Low cross network To minimize delay issues and allow opportunity to use the signaling to detect idle channels. delay (latency) normal interactive conversation (This is not a requirement for broadcast applications) b) Voice switching Limited variation in Here, the ATM network interprets the voice signaling To minimize delays and allow effective delay echo cancellation information and routes the call across the network. In Network infrastructure CHAPTER 3.2 4. Structured J2 n * 64 kbps (fractional J2) service. Table 3.2-4 Objectives to be achieved-2. 5. Unstructured J2 (6312 Mbps) service. Characteristics Necessity Figure 3.2-3 shows two ATM circuit emulation services Signaling analysis To allow set up and tear-down of (CES) interworking functions (IWFs) connected to an circuits on demand (or allocation and release of resources) ATM network via physical UNI interfaces. The other sides of the CES-IWFs are connected to standard CBR Call switching and routing To allow configuration of circuits (e.g., DS1/DS3, J2, or E1/E3), which may mechanisms "real-world" VPN applications originate, for example, on a user's PBX. The job of the Silence suppression or VBR To realize statistical gain two IWFs is to extend this CBR circuit over the ATM encoding (provides at least a doubling network. This means an ATM portion of the connection in performance) should retain the bit integrity- that is, analog signal loss cannot be inserted and voice echo control cannot be Call Admission Control (CAC) To ensure QoS is preserved performed. These must be performed either by the DTE Network resource utilization To allow statistical overbooking or before the ATM CES IWF is encountered. An ATM of network resources UNI physical interface has two 