ABSTRACT: This release of the popular Telcordia Notes on . . . series, Telcordia Notes on IP Centrex, discusses IP Centrex from the network architecture, deployment, and marketing perspectives.

IP Centrex is a network-based service that uses VOIP in the enterprises LAN and on the broadband access facility to the service provider's network. IP Centrex can provide a number of new capabilities and benefits for enterprise customers and their service providers.

Readers will learn:

• the two major architectural approaches for offering IP Centrex, including the network equipment and Customer Premises Equipment (CPE) required for each approach
• the benefits and applications that IP Centrex customers can enjoy
• the advantages IP Centrex offers to service providers
• the technical hurdles that equipment suppliers and service providers must address before IP Centrex service can be offered
• how IP Centrex and IP PBX compare to each other.

• Enterprise customers currently using conventional Centrex or conventional PBX's. The information in this SR can help customers in their discussions with potential service providers or PBX suppliers. (Note the SR does not discuss the capabilities of any particular PBX model or Centrex offering.)
• Service providers, including Local Exchange Carriers and Application Service Providers. The information in this SR can help service providers better evaluate various alternatives as they formulate IP Centrex plans.
• Suppliers of IP Centrex network equipment or CPE. The information in this SR can help equipment suppliers better understand the challenges that their service provider customers are facing.