Prestige 2602HW Series User’s Guide

Figure 49 SIP Redirect Server

9.2.3.4 SIP Register Server

ASIP register server maintains a database of SIP identity-to-IP address (or domain name) mapping. The register server checks your user name and password when you register.

9.2.4RTP

When you make a VoIP call using SIP, the RTP (Real time Transport Protocol) is used to handle voice data transfer. See RFC 1889 for details on RTP.

9.3 SIP ALG

The Prestige 2602HW is a SIP Application Layer Gateway (ALG). A SIP ALG allows VoIP calls to pass through NAT by examining and translating IP addresses embedded in the data stream. When a VoIP device behind the Prestige registers with the SIP register server, the Prestige translates the device’s private IP address inside the SIP data stream to a public IP address. You do not need to use STUN with a VoIP device that is behind the Prestige 2602HW.

9.4 Pulse Code Modulation

Pulse Code Modulation (PCM) measures analog signal amplitudes at regular time intervals and converts them into bits.

Chapter 9 Introduction to VoIP

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