ABSTRACT: While distributed, open service interface, switching architectures ("softswitch" architectures) offer great promise in improving telephony services in the 21st century, the large embedded base of class 5 local digital switching systems will continue to provide dial tone services for many years to come. Service providers with a large embedded base of class 5 digital switching systems are deploying broadband access systems to their residential and small/medium business customers. These service providers need to maximize the service potential of their broadband access facilities by providing a mixture of narrowband and broadband multimedia services, including voice services.

Integrated Digital Loop Carrier (IDLC) access systems have provided an important platform for voice service transport to embedded class 5 local digital switching systems for over 15 years. GR-3109, Generic Criteria for Packet Voice Integrated Digital Loop Carrier (PV-IDLC) Systems, helps access system and device suppliers leverage this proven network access interface by providing valuable information on what existing Telcordia access network generic criteria (GR) should be applied to the PV-IDLC system, and what new criteria are necessary to help insure that PSTN-quality voice service is provided. Guidance is also provided to system and device suppliers on capabilities needed to effectively transition customer lines (on a per-line basis) to the emerging softswitch service environment. Applying GR-3109 criteria to packet voice access systems will assist system suppliers in avoiding undesirable system retrofits when interconnecting to a local exchange carrier's (LEC) emerging softswitch service environment.

GR-3109 describes how existing Telcordia IDLC generic requirements should be applied to PV-IDLC systems and augments these generic requirements based on the unique challenges presented by packet voice transport and emerging broadband packet access architectures. The work defines a packet voice endpoint (PVE) function that exists in the network as part of a broadband Remote Digital Terminal (PVE-A), in the network as part of a FTTx ONU-like device (PVE-B), or in a customer-owned device (PVE-C). A Network Gateway (NGW) provides the network-side packet voice-to-TDM voice conversion and IDLC interface functions, as well as serving as a point for providing additional functionality in support of transitioning customer lines to the emerging softswitch service environment (e.g., network protection, voice quality monitoring, conference bridging, and signaling concentration).

GR-3109 provides system criteria on the PVE function(s), the NGW function, and the broadband access network (BAN) that interconnect these elements. System criteria addressed includes:

• voice quality planning
• voice quality control (e.g., loss insertion, packet loss, delay, and packet delay variation)
• packet voice impairment mitigation
• system failure behaviors
• system behaviors during overload and congestion conditions