Operation Manual – Process Server Configuration
H3C XE 200/2000 IP PBX
Chapter 4 SIP Overview
4-6
calling and called endpoints thus can send request and response to each other
bypassing the SIP proxy server. See the following figure.
Internet
SIP Server
VG
(User Agent)
INVITE
100 TRYING
100 TRYING
200 OK
301 Moved Permanently
INVITE
VG
(User Agent)
Figure 4-4
Call redirect procedures for UAs
This is a common application. Fundamentally, a redirect server can respond with the
address of a proxy server as well. The subsequent call procedures are the same as the
call procedures involving proxy servers.
4.1.4 SIP Messages
SIP messages are text-coded and fall into two categories: request and response.
SIP requests include INVITE, ACK, OPTIONS, BYE, CANCEL, REGISTER and so on.
Their functions are described in the following table.
Table 4-1
Functions of SIP request messages
Message
Function
INVITE
Invites a user to join a call
ACK request
Confirms a response
OPTIONS
Requests capability negotiation
BYE
Releases a call that has been established
CANCEL
Releases a call that has not been established
REGISTER
Registers user information such as location with a SIP registrar
Summary of Contents for XE 200/2000 IP
Page 7: ...Basic Configuration ...
Page 42: ...Process Server Configuration ...
Page 82: ...Location Server Configuration ...
Page 182: ...Feature ...
Page 259: ...System Management ...
Page 341: ...IP Performance and Application ...
Page 349: ...Media Server ...
Page 360: ...Call Services ...
Page 507: ...Appendix A ...
Page 511: ...Appendix B ...