I'm sure Alex is going to chime in here eventually but standard SIP Session Timers (RFC 4028) only require support from one endpoint and can use either re-INVITEs or UPDATE. The answer to his question is most likely yes ;). On Tue, Jun 7, 2011 at 4:55 PM, anorexicpoodle <anorexicpoodle at gmail.com> wrote:
Nope probably not.
Im not familliar with Broadsofts method, but Metaswitch does something similar, and instead of using session timers, uses regular re-invites to detect if all involved endpoints are still alive.
We found this a little heavy handed with their stock timers, so we fiddled with it until we were happy.
I suspect the rationale here is that using RFC 4028 depends on both far ends supporting that RFC, and implementing it properly, which takes the control out of the softswitch's hands. Using a re-invite as a polling mechanism guarantees the polling works with even older (or cheaper) SIP endpoints that dont support session timers.
-- Kristian Kielhofner