Appendix
1065
The call cannot be set up successfully.
User A
Proxy Server
User B
F1. INVITE B
F2. INVITE B
F3. 100 Trying
F4. 100 Trying
F5. 486 Busy Here
F6. 486 Busy Here
F7. ACK
F8. ACK
Step
Action
Description
F1
INVITE—User A to Proxy Server
User A sends the INVITE message to a
proxy server. The INVITE request is an
invitation to User B to participate in a 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. Proxy server forwards
the INVITE message to User B.
F3
100 Trying—User B to Proxy
Server
User B sends a SIP 100 Trying response to
the proxy server. The 100 Trying response
indicates that the INVITE request has been
Summary of Contents for SIP-T54S
Page 1: ...63...
Page 51: ...Getting Started 25 For SIP T46G S Desk Mount Method Wall Mount Method Optional...
Page 53: ...Getting Started 27 For SIP T42S T41S Desk Mount Method Wall Mount Method Optional...
Page 55: ...Getting Started 29 For SIP T23P T23G Desk Mount Method Wall Mount Method Optional...
Page 70: ...Administrator s Guide for SIP T2 Series T19 P E2 T4 Series T5 Series CP860 CP920 IP Phones 44...
Page 194: ...Administrator s Guide for SIP T2 Series T19 P E2 T4 Series T5 Series CP860 CP920 IP Phones 168...
