Authorization Requirements
SIP registrations (and subsequent SIP requests) require a username and password for
authorization. These credentials are validated via a challenge / response system using the
HTTP digest mechanism (as detailed in RFC3261, "SIP: Session Initiation Protocol").
SIP Servers
SIP is a client-server protocol. A SIP client is an application program or device that sends SIP
requests. A SIP server responds to the SIP requests.
When you use SIP to make a VoIP call, it originates at a client and terminates at a server
. A
SIP client could be a computer or a SIP phone. One device can act as both a SIP client and a
SIP server.
SIP User Agent
A SIP user agent can make and receive VoIP telephone calls. This means that SIP can be used
for peer-to-peer communications even though it is a client-server protocol. In the following
figure, either A or B can act as a SIP user agent client to initiate a call. A and B can also both
act as a SIP user agent to receive the call.
Figure 15-7 SIP User Agent
SIP Proxy Server
SIP Proxy Server
A SIP proxy server receives requests from clients and forwards them to another server
.
In the following example, you want to use client device A
to call someone who is using client
device C.
Step 1 The client device (A in the figure) sends a call invitation to the SIP proxy server B.
Step 2 The SIP proxy server forwards the call invitation to C.
LTE CPE B2368
User Guide
15 VoIP
Issue 03 (2019-01-31) Copyright © Huawei Technologies Co., Ltd. 126
To Next Page
Loading...
