Hi, We're looking at significantly increasing the TCP NAT'd endpoint registration expires value on access SBCs for a couple reasons. 1) Reduce RPS on the SBC 2) Better support mobile voip apps (specifically on iOS) We're more or less a Polycom shop. Other than the mobile app only our BLF traffic has been using TCP and our reg-expire is at 90 seconds. The app seems to tolerate an expire of 1200 with no issues, and we'll be testing the Polycoms to see if we're breaking anything there. ( read there's a historical, 2009, issue with Polycoms and reg-expire above 120 ) All that said - I'm curious if anyone here has TCP reg-expire experiences they'd like to share. Regards, Russ