User's Manual

Chapter 21 Voice 187

The following figure shows the SIP and session traffic flow between the user agents (UA

1 and UA 2)

and the proxy servers (this example shows two proxy servers, PROXY 1 and PROXY 2).

Figure 116 SI

P Call Through Proxy Servers

UA 1

UA 2

PROXY 1

PROXY 2

SIP

SIP & RTP

The following table shows the SIP call progression.

Table 105 SIP Call Progression

UA 1 PROXY 1 PROXY 2 UA 2

Invite

100 Trying Invite

100 Trying

180

Ringing

180

Ringing

180

Ringing

200 OK

ACK

RTP RTP