Internet Communications Using SIP : Delivering VoIP and Multimedia Services With Session Initiation Protocol {2Nd Ed.}

Figure 11.3 PSTN-to-SIP call

Table 11.1 ISUP IAM Message and Field Description

INITIAL ADDRESS MESSAGE (IAM) DESCRIPTION

CgPN=314-555-1111,NPI=E.164, Calling Party Number

NOA=National

CdPN=972-555-2222,NPI=E.164, Called Party Number,

NOA=National Numbering Plan Indicator,

Nature of Address

USI=Speech User Service Information

FCI=Normal Forward Call Indicator

CPC=Normal Calling Party’s Category

CCI=Not Required Call Charge Indicator

PSTN Switch Gateway SIP User Agent

One way Speech

Two way Speech

1 IAM

5 ACM

10 BYE

8 ACK

RTP Media Session

2 INVITE

3 100 Trying

4 180 Ringing

6 200 OK

7 ANM

11 RLC

No Speech Path No Media Session

12 200 OK

9 REL

SIP Telephony 191