Yealink Yealink SIP-T46G, Руководство администратора

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Administrator’s Guide for SIP-T2_Series_T4_Series IP Phones
602
Step Action Description
call session.
In the INVITE request:

The IP address of User B is inserted
in the Request-URI field.

User A is identified as the call
session initiator in the From field.

A unique numeric identifier is
assigned to the call and is inserted
in the Call-ID field.

The transaction number within a
single call leg is identified in the
CSeq field.

The media capability User A is
ready to receive is specified.

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.