18 Dec
2021
18 Dec
'21
9:27 a.m.
Mojtaba writes:
Let' me describe the scenario:
<UE>---------><SEMS>-----------><ASTERISK>
The UE tries to make calls, The first INVITE message is without an
Authentication header. The Asterisk server returns 401 Unauthorized.
The UE sends again INVITE messages to the asterisk server. The second
INVITE message has an Authentication header. Because both INVITE messages
have the same CSeq, the asterisk server thinks this is a LOOP message and
sends 401 Unautirozed messages again.
In both cases, the Sems set "CSeq: 10 INVITE" header, while the second the
INVITE message is not re-invite message and the CSeq should be set
incremental.
As I already quoted, RFC 3261 specifies:
8.1.1.5 CSeq
For non-REGISTER requests outside of a dialog, the sequence number
value is arbitrary.
Section 12.1 tells how dialogs are created:
Dialogs are created through the generation of non-failure responses
to requests with specific methods. Within this specification, only
2xx and 101-199 responses with a To tag, where the request was
INVITE, will establish a dialog.
401 is a failure response. Thus no dialog is created and in the second
INVITE sems is allowed to use whatever CSeq value.
If Asterisk does not allow that, complain Asterisk about it.
-- Juha