The purpose of the Progress indicator information element is to describe an event which has occurred during the life of a call. The information element may occur two times in a message.
The Progress indicator information element is coded as shown in Figure 4-29 and Table 4-20.
The maximum length of this information element is four octets.
Bits |
||||||||
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
Octets |
Progress indicator Information element identifier |
||||||||
0 |
0 |
0 |
1 |
1 |
1 |
1 |
1 |
1 |
Length of progress indicator contents |
2 |
|||||||
1 ext. |
Coding |
0 |
Location |
3 |
||||
1 ext. |
Progress description |
4 |
||||||
Progress indicator information element
Progress indicator information element
Coding standard (octet 3) |
|
Bits |
|
7 6 |
|
0 0 |
CCITT standardized coding, as described below |
0 1 |
ISO/IEC standard (Note 1) |
1 0 |
National standard (Note 1) |
1 1 |
Standard specific to identified location (Note 1) |
Note 1 - These other coding standards should be used only when the desired progress indication can not be represented with the ITU-T-standardized coding. |
|
Location (octet 3) |
|
Bits |
|
4 3 2 1 |
|
0 0 0 0 |
User |
0 0 0 1 |
Private network serving the local user |
0 0 1 0 |
Public network serving the local user |
0 0 1 1 |
Transit network (Note 2) |
0 1 0 0 |
Public network serving the remote user |
0 1 0 1 |
Private network serving the remote user |
1 0 1 0 |
Network beyond the interworking point |
All other values are reserved. |
|
Note 2 - This value may be generated by some networks. Note 3 - Depending on the location of the users, the local public network and remote public network may be the same network. |
|
Progress description (octet 4) |
|
Bits |
|
7 6 5 4 3 2 1 |
No. |
0 0 0 0 0 0 1 |
1. Call is not end-to-end ISDN; further call progress information may be available in.band |
0 0 0 0 0 1 0 |
2. Destination address is non ISDN |
0 0 0 0 0 1 1 |
3. Origination address is non ISDN |
0 0 0 0 1 0 0 |
4. Call has returned to the ISDN |
0 0 0 0 1 0 1 |
5. Interworking has occurred and has resulted in a telecommunication service change (Note 5) |
0 0 0 1 0 0 0 |
8. In-band information or an appropriate pattern is now available. |
All other values are reserved. |
|
Note 4 - The use of different progress descriptions is further explained in Annex G. Note 5 - This progress description value shall be used only in the case of interworking in a full ISDN environment, e.g. when bearer capability selection is not supported or when resource or route of the preferred capability is not available. In case of interworking with a non-ISDN environment a progress description No. 1 shall be used. If the destination address is non-ISDN, the progress description No. 2 shall be used. |
|