Introduction To Voip; Sip; Sip Identities; Sip Number - ZyXEL Communications PRESTIGE 2602R Series User Manual

This chapter provides background information on VoIP and SIP.

7.1 Introduction to VoIP

VoIP is the sending of voice signals over the Internet Protocol. This allows you to make phone
calls and send faxes over the Internet at a fraction of the cost of using the traditional circuit-
switched telephone network. You can also use servers to run telephone service applications
like PBX services and voice mail. Internet Telephony Service Provider (ITSP) companies
provide VoIP service. A company could alternatively set up an IP-PBX and provide it's own
VoIP service.
Circuit-switched telephone networks require 64 kilobits per second (Kbps) in each direction to
handle a telephone call. VoIP can use advanced voice coding techniques with compression to
reduce the required bandwidth.

7.2 SIP

The Session Initiation Protocol (SIP) is an application-layer control (signaling) protocol that
handles the setting up, altering and tearing down of voice and multimedia sessions over the
Internet.
SIP signaling is separate from the media for which it handles sessions. The media that is
exchanged during the session can use a different path from that of the signaling. SIP handles
telephone calls and can interface with traditional circuit-switched telephone networks.

7.2.1 SIP Identities

A SIP account's Uniform Resource Identifier (URI) identifies the SIP account in a way similar
to the way an e-mail address identifies an e-mail account. It is also known as a SIP identity or
address. The format of a SIP identity is SIP-Number@SIP-Service-Domain.

7.2.1.1 SIP Number

A SIP number is the part of the SIP URI that comes before the "@" symbol. For example, if
1122334455@VoIP-provider.com was your SIP URI, "1122334455" would be your SIP
number.
Chapter 7 Introduction to VoIP
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Introduction to VoIP
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