Appendix
989
Step
Action
Description
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
200 OK—User B to Proxy
Server
User B sends a SIP 200 OK response to
the proxy server. The 200 OK response
notifies proxy server that the connection
has been made.
F6
200 OK—Proxy Server to User
A
The proxy server forwards the 200 OK
message to User A. The 200 OK
response notifies User A that the
connection has been made.
F7
ACK—User A to Proxy Server
User A sends a SIP ACK to the proxy
server, The ACK confirms that User A
has received the 200 OK response. The
call session is now active.
F8
ACK—Proxy Server to User B
The proxy server sends the SIP ACK to
User B. The ACK confirms that the proxy
server has received the 200 OK
response. The call session is now active.
Summary of Contents for CD860
Page 1: ......
Page 45: ...Getting Started 23 For SIP T42G T41P T40P Desk Mount Method Wall Mount Method Optional ...
Page 47: ...Getting Started 25 For SIP T23P T23G Desk Mount Method Wall Mount Method Optional ...
Page 122: ...Administrator s Guide for SIP T2 Series T19 P E2 T4 Series CP860 IP Phones 100 ...
Page 840: ...Administrator s Guide for SIP T2 Series T19 P E2 T4 Series CP860 IP Phones 818 ...
Page 995: ...Appendix 973 ...