Yealink SIP-T19 E2 T4 Series, Руководство администратора

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Administrator’s Guide for SIP-T2 Series/T19(P) E2/T4 Series/T5 Series IP Phones
950
Step Action Description

The port on which User B is prepared
to receive the RTP data is specified.
F2 INVITE—Proxy Server to User B
The proxy server maps the SIP URI in the To
field to User B. The proxy server sends the
INVITE message to User B.
F3
180 Ringing—User B to Proxy
Server
User B sends a SIP 180 Ringing response to
the proxy server. The 180 Ringing response
indicates that the user is being alerted.
F4
180 Ringing—Proxy Server to
User A
The proxy server forwards the 180 Ringing
response to User A. User A hears the
ring-back tone indicating that User B is
being alerted.
F5
302 Move Temporarily—User B to
Proxy Server
User B sends a SIP 302 Moved Temporarily
message to the proxy server. The message
indicates that User B is not available at SIP
phone B. User B rewrites the contact-URI.
F6 ACK—Proxy Server to User B
The proxy server sends a SIP ACK to User B,
the ACK message notifies User B that the
proxy server has received the ACK message.
F7
302 Move Temporarily—Proxy
Server to User A The proxy server forwards the 302 Moved
Temporarily message to User A.
F8 ACK—User A to Proxy Server
User A sends a SIP ACK to the proxy server.
The ACK message notifies the proxy server
that User A has received the ACK message.
F9 INVITE—User A to Proxy Server
User A sends a SIP INVITE request to the
proxy server. In the INVITE request, a
unique Call-ID is generated and the
Contact-URI field indicates that User A
requests the call.
F10 INVITE—Proxy Server to User C
The proxy server forwards the SIP INVITE
request to User C.
F11
180 Ringing—User C to Proxy
Server
User C sends a SIP 180 Ringing response to
the proxy server. The 180 Ringing response
indicates that the user is being alerted.
F12
180 Ringing—Proxy Server to
User A
The proxy server forwards the 180 Ringing
response to User A. User A hears the
ring-back tone indicating that User C is
being alerted.