[OpenSIPS-Users] OpenSIPS migth be changing CSeq numbers after SIP OPTIONS. How to avoid it?
Rodrigo Pimenta Carvalho
pimenta at inatel.br
Wed Jun 7 16:04:58 EDT 2017
Dear OpenSIPS users,
I'm facing a problem related to CSeq numbers in SIP messages and maybe it is being caused by SIP OPTIONS messages.
When a caller sends a SIP ACK to the callee, the SIP ACK has CSeq = 2. However, after being relayed by OpenSIPS, the CSeq number become 3.
It seems that OpenSIPS decided to change such value on its own. But, maybe it was caused by the previous SIP OPTIONS message receive before.
The diagram bellow shows what is happening.
Can the SIP OPTIONS message cause such issue? If yes, should I give up of using SIP OPTIONS? Can it be a bug in OpenSIPS?
If not, what is happening here??
If that CSeq remains like 3, the callee will simply discard the SIP ACK and send another SIP OK, will not discard?
Caller OpenSIPs Callee
| | |
| | |
| INVITE | |
| CSeq = 2 | |
|------------------------------->| INVITE |
| | CSeq = 2 |
| |------------------------------->|
| | |
| | TRYING |
| | CSeq = 2 |
| TRYING |<-------------------------------|
| CSeq = 2 | |
|<-------------------------------| |
| | |
| | RING |
| | CSeq = 2 |
| RING |<-------------------------------|
| CSeq = 2 | |
|<-------------------------------| |
| | SIP OK |
| | CSeq = 2 |
| SIP OK |<-------------------------------|
| CSeq = 2 | |
|<-------------------------------| |
| | SIP OK |
| | CSeq = 2 |
| SIP OK |<-------------------------------|
| CSeq = 2 | |
|<-------------------------------| |
| | |
| | SIP OPTIONS |
| | CSeq = 3 | <<---- new CSeq
| |<-------------------------------|
| | |
| | SIP 500 |
| | CSeq = 3 |
| |------------------------------->|
| ACK | |
| CSeq = 2 | |
|------------------------------->| ACK |
| | CSeq = 3 | <<---- Cseq of ACK was changed by OpenSIPS.
| |------------------------------->|
| ACK | |
| CSeq = 2 | |
|------------------------------->| ACK |
| | CSeq = 3 |
| |------------------------------->|
| | |
| | SIP OK |
| | CSeq = 2 |
| SIP OK |<-------------------------------|
| CSeq = 2 | |
|<-------------------------------| |
| ACK | |
| CSeq = 2 | |
|------------------------------->| ACK |
| | CSeq = 3 |
| |------------------------------->|
| | |
| | SIP OK |
| | CSeq = 2 |
| |<-------------------------------| <<------- This SIP OK never receives a SIP ACK with CSeq = 2...and the problem continues.
Any hint will be very helpful!!
Best regards!
RODRIGO PIMENTA CARVALHO
Inatel Competence Center
Software
Ph: +55 35 3471 9200 RAMAL 979
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