Just to avoid any confusion, the doc should be updated with a diagram:
For a successful call we have:
```
UAC proxy UAS presence server
|--INVITE->| | |
|<-100-----|--INVITE->| |
| |--PUBLISH(trying)----->|
| |<-100-----| |
| | | |
| |<-18x-----| |
|<-18x-----|--PUBLISH(early)------>|
| | | |
| |<-200-----| |
|<-200-----|--PUBLISH(confirmed)-->|
|--ACK---->| | |
| |--ACK---->| |
| | | |
```
If we choose to avoid the "trying" state, then "early" will be triggered on
the first 18x provisional reply.
Something like this:
```
UAC proxy UAS presence server
|--INVITE->| | |
|<-100-----|--INVITE->| |
| |<-100-----| |
| | | |
| |<-18x-----| |
|<-18x-----|--PUBLISH(early)------>|
| | | |
| |<-200-----| |
|<-200-----|--PUBLISH(confirmed)-->|
|--ACK---->| | |
| |--ACK---->| |
| | | |
```
The issue is with rejected calls. If we don't have a 18x provisional reply,
then we have this:
```
UAC proxy UAS presence server
|--INVITE->| | |
|<-100-----|--INVITE->| |
| |--PUBLISH(trying)----->|
| |<-100-----| |
| | | |
| |<-456xx---| |
| |--PUBLISH(terminated)->|
|<-456xx---|--ACK---->| |
|--ACK---->| | |
```
If we don't have a 18x provisional reply and we avoid the "trying" state, then
we don't have any PUBLISH at all:
```
UAC proxy UAS presence server
|--INVITE->| | |
|<-100-----|--INVITE->| |
| |<-100-----| |
| | | |
| |<-456xx---| |
|<-456xx---|--ACK---->| |
|--ACK---->| | |
```
---
Reply to this email directly or view it on GitHub:
https://github.com/OpenSIPS/opensips/issues/142#issuecomment-30758792
_______________________________________________
Devel mailing list
Devel@lists.opensips.org
http://lists.opensips.org/cgi-bin/mailman/listinfo/devel
