[OpenSIPS-Users] To tag in the CANCEL issue

[Alex Balashov]

Well, the vendor is just mistaken. ;-) 

CANCELs are generated internally by the proxy, since they're a hop-by-hop construct. You're going to have a hard time influencing their content on that level. The vendor's suggestion is, quite frankly, ludicrous.

-- Alex

> On Nov 25, 2024, at 1:16 am, nz deals <nzdealshelp at gmail.com> wrote:
> 
> Thanks Alex.
> I raised this issue with Vendor support, and their suggestion was to include the To-tag in the CANCEL request, given that the 180 Ringing and 183 Session Progress responses from the Cisco phone include To-tags. Based on their feedback, they believe the absence of the To-tag in the CANCEL might be contributing to the rejection with a 481 Call/Transaction Does Not Exist error.
> From my observations, my SBC adheres to SIP standards, but since this behavior aligns with Vendor's recommendation and might help address the issue, I wanted to explore this approach as a potential workaround.
> 
> Regards,
> Jason
> 
> On Mon, 25 Nov 2024 at 17:46, Alex Balashov <abalashov at evaristesys.com> wrote:
> Hi,
> 
> Initial INVITEs do not ever have a To-tag. So, the initial INVITE didn't have a To-tag, not because of any quirk or eccentricity, but because initial INVITEs aren't supposed to have To-tags. If the initial INVITE being CANCEL'd doesn't have a To-tag, the CANCEL shouldn't have a To-tag. The CANCEL should not have a To-tag.
> 
> I suspect your theory of why the CANCEL is being rejected by the Cisco phone is not correct.
> 
> -- Alex
> 
> > On Nov 24, 2024, at 10:42 pm, nz deals <nzdealshelp at gmail.com> wrote:
> > 
> > Does anyone have any thoughts or input on this?
> > 
> > Thanks
> > 
> > Regards,
> > Jason
> > 
> > On Mon, 18 Nov 2024 at 10:20, nz deals <nzdealshelp at gmail.com> wrote:
> > Hi Community
> > I’m encountering a strange issue with CANCEL requests in my opensips 3.4.2 setup. Here’s the scenario:
> >     • My carrier sends the initial INVITE without a tag in the To header, which I forward to a Cisco phone.
> >     • The Cisco phone responds with a 180 Ringing message, which includes a tag in the To header.
> >     • When I send a CANCEL request, my carrier does not include the tag in the To header, and as a result, OpenSIPS also forwards the CANCEL to the Cisco phone without the tag.
> > Because of this, the Cisco phone responds with a 481 Call/Transaction Does Not Exist error, and the call remains active on the phone without being canceled.
> > I’ve tried modifying the CANCEL request to include the tag in the To header, but I wasn’t able to modify because the initial INVITE doesn’t have a tag in the To header.
> > Has anyone experienced a similar issue or found a way to fix this? Any guidance would be greatly appreciated.
> > 
> > Thanks
> > 
> > Regards,
> > Jason
> > _______________________________________________
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> > Users at lists.opensips.org
> > http://lists.opensips.org/cgi-bin/mailman/listinfo/users
> 
> -- 
> Alex Balashov
> Principal Consultant
> Evariste Systems LLC
> Web: https://evaristesys.com
> Tel: +1-706-510-6800
> 
> 
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-- 
Alex Balashov
Principal Consultant
Evariste Systems LLC
Web: https://evaristesys.com
Tel: +1-706-510-6800