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Chapter 23 Voice
VMG8825-B Series User’s Guide
248
1
A
sends a SIP INVITE request to
B
. This message is an invitation for
B
to participate in a SIP telephone call.
2
B
sends a response indicating that the telephone is ringing.
3
B
sends an OK response after the call is answered.
4
A
then sends an ACK message to acknowledge that
B
has answered the call.
5
Now
A
and
B
exchange voice media (talk).
6
After talking,
A
hangs up and sends a BYE request.
7
B
replies with an OK response confirming receipt of the BYE request and the call is terminated.
SIP Call Progression Through Proxy Servers
Usually, the SIP UAC sets up a phone call 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.
The following figure shows the SIP and session traffic flow between the user agents (
UA 1
and
UA 2
) and
the proxy servers (this example shows two proxy servers,
PROXY 1
and
PROXY 2
).
3. OK
4. ACK
5.Dialogue (voice traffic)
6. BYE
7. OK
Table 112 SIP Call Progression (continued)
A
B
Содержание VMG8825-B Series
Страница 15: ...15 PART I User s Guide...
Страница 65: ...65 PART II Technical Reference...
Страница 204: ...Chapter 17 Home Connectivity VMG8825 B Series User s Guide 204 Figure 115 Network Setting Home Connectivity...
Страница 231: ...Chapter 23 Voice VMG8825 B Series User s Guide 231 Figure 139 VoIP SIP SIP Account Add new account Edit...
Страница 236: ...Chapter 23 Voice VMG8825 B Series User s Guide 236 Figure 141 VoIP SIP SIP Service Provider Add new provider Edit...
Страница 297: ...Chapter 40 Firmware Upgrade VMG8825 B Series User s Guide 297 Figure 182 Error Message...
Страница 313: ...313 PART III Appendices Appendices contain general information Some information may not apply to your device...
Страница 360: ...Index VMG8825 B Series User s Guide 360 Z ZyXEL Family Safety page 217...