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Chapter 11 Voice
P-2602HWLNI User’s Guide
173
11.2.3 RTP
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.
11.2.4 Pulse Code Modulation
Pulse Code Modulation (PCM) measures analog signal amplitudes at regular time intervals
and converts them into bits.
11.2.5 SIP Call Progression
The following figure displays the basic steps in the setup and tear down of a SIP call. A calls
B.
A sends a SIP INVITE request to B. This message is an invitation for B to participate in a SIP
telephone call.
4
B sends a response indicating that the telephone is ringing.
5
B sends an OK response after the call is answered.
6
A then sends an ACK message to acknowledge that B has answered the call.
7
Now A and B exchange voice media (talk).
8
After talking, A hangs up and sends a BYE request.
9
B replies with an OK response confirming receipt of the BYE request and the call is
terminated.
11.2.6 SIP Call Progression Through Proxies
Usually, the SIP UAC sets up a phonecall by sending a request to the SIP proxy server. Then,
the proxy server looks up the destination to which the call should be forwarded (according to
the URI requested by the SIP UAC). The request may be forwarded to more than one proxy
server before arriving at its destination.
The response to the request goes to all the proxy servers through which the request passed, in
reverse sequence. Once the session is set up, session traffic is sent between the UAs directly,
bypassing all the proxy servers in between.
Table 58
SIP Call Progression
A
B
1. INVITE
2. Ringing
3. OK
4. ACK
5.Dialogue (voice traffic)
6. BYE
7. OK
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Страница 7: ...Safety Warnings P 2602HWLNI User s Guide 7...
Страница 8: ...Safety Warnings P 2602HWLNI User s Guide 8...
Страница 24: ...Table of Contents P 2602HWLNI User s Guide 24...
Страница 32: ...List of Figures P 2602HWLNI User s Guide 32...
Страница 38: ...List of Tables P 2602HWLNI User s Guide 38...
Страница 39: ...39 PART I Introduction Introducing the ZyXEL Device 41 Introducing the Web Configurator 49...
Страница 40: ...40...
Страница 60: ...Chapter 2 Introducing the Web Configurator P 2602HWLNI User s Guide 60...
Страница 62: ...62...
Страница 86: ...Chapter 5 Bandwidth Management Wizard P 2602HWLNI User s Guide 86...
Страница 98: ...Chapter 6 Status Screens P 2602HWLNI User s Guide 98...
Страница 99: ...99 PART III Network WAN Setup 101 LAN Setup 117 Wireless LAN 129 Network Address Translation NAT Screens 155...
Страница 100: ...100...
Страница 154: ...Chapter 9 Wireless LAN P 2602HWLNI User s Guide 154...
Страница 166: ...Chapter 10 Network Address Translation NAT Screens P 2602HWLNI User s Guide 166...
Страница 167: ...167 PART IV VoIP Voice 169 VoIP Trunking 211 Phone Usage 227...
Страница 168: ...168...
Страница 226: ...Chapter 12 VoIP Trunking P 2602HWLNI User s Guide 226...
Страница 230: ...Chapter 13 Phone Usage P 2602HWLNI User s Guide 230...
Страница 232: ...232...
Страница 264: ...Chapter 15 Firewall Configuration P 2602HWLNI User s Guide 264...
Страница 268: ...Chapter 16 Content Filtering P 2602HWLNI User s Guide 268...
Страница 274: ...Chapter 17 Introduction to IPSec P 2602HWLNI User s Guide 274...
Страница 309: ...Chapter 19 Certificates P 2602HWLNI User s Guide 309 Figure 173 My Certificate Details...
Страница 320: ...Chapter 19 Certificates P 2602HWLNI User s Guide 320 Figure 181 Trusted Remote Host Details...
Страница 326: ...326...
Страница 330: ...Chapter 20 Static Route P 2602HWLNI User s Guide 330...
Страница 338: ...Chapter 21 Bandwidth Management P 2602HWLNI User s Guide 338...
Страница 342: ...Chapter 22 Dynamic DNS Setup P 2602HWLNI User s Guide 342...
Страница 360: ...Chapter 23 Remote Management Configuration P 2602HWLNI User s Guide 360...
Страница 372: ...Chapter 24 Universal Plug and Play UPnP P 2602HWLNI User s Guide 372...
Страница 374: ...374...
Страница 380: ...Chapter 25 System P 2602HWLNI User s Guide 380...
Страница 406: ...Chapter 28 Troubleshooting P 2602HWLNI User s Guide 406...
Страница 422: ...Chapter 30 Diagnostic P 2602HWLNI User s Guide 422...
Страница 432: ...Chapter 31 Product Specifications P 2602HWLNI User s Guide 432...
Страница 434: ...434...
Страница 446: ...Appendix A Setting up Your Computer s IP Address P 2602HWLNI User s Guide 446...
Страница 482: ...Appendix F Legal Information P 2602HWLNI User s Guide 482...
Страница 488: ...Appendix G Customer Support P 2602HWLNI User s Guide 488...