IP-to-IP Gateway Overview

VoIP has gained acceptance with enterprise, service provider, and commercial customers, and the migration of voice traffic from public switched telephone network (PSTN) to voice traffic over the IP network is underway. Increasing numbers of customers, looking for richer services than the PSTN can provide, are starting to interconnect their VoIP networks. However, interconnecting disparate VoIP networks has a new set of challenges that need to be dealt with. These new network requirements include the following:

• Creating proper points of demarcation between enterprises and service providers, primarily for providing security and collection of call detail records (CDRs) for voice quality statistics and billing.
• Hiding internal network topology from the peering partner or the outside world for security purposes.
• Providing interworking between H.323 and Session Initiation Protocol (SIP)
• Addressing various other challenges, such as transcoding media, routing VoIP traffic to traverse firewalls and Network Address Translation (NAT), ensuring quality of service (QoS), and employing call admission control (CAC).