pascal supports putting set_var in global sip templates.
if sccp support is relevant, can modify wazo-confgend to also use a set_var.

What we’ve found is that the sip.js does not support session-timers, so we can’t use those for the moment, at least not for web/desktop/mobile apps.

One potential issue is that the effect of this timeout seems hidden. There’s no explicit message that explain the origin of the hangup. Even in debug 9 logging it does not seem obvious what’s happening.

Would it be appropriate to update the default global SIP template with a set_var for TIMEOUT(absolute)=36000? This would allow admins to override that value if they want. Would require a migration?

Alternatively, we could update the extensions_lib_did.conf dialplan to set this timeout through a global variable(the TIMEOUT(absolute) function itself cannot be set as a global var it seems). This would cover incoming calls. Could do the same for e.g. outcalls in extensions_lib_outcall.conf . Is there a way to affect both incalls, outcalls and internal calls in the same way without updating dialplan all over?

SET(TIMEOUT(absolute)=10) does hangup calls after 10 seconds, unconditionally, based on a test with a call to a holding bridge. This is a simple solution to put an absolute limit on all calls indepent on their status.
It can be configured manually through the set_var option of the global SIP template, affecting all SIP endpoints.