Carriers that refused imsd's periodic re-registration. On O2 UK every 30-minute refresh was answered 503, followed by up to 20 minutes without service while imsd waited out the network's Retry-After. The re-REGISTER now carries the registration's authentication answer and proposes new IPsec parameters, as 3GPP TS 24.229 requires. A registration carried over from before the upgrade keeps the old form until its next fresh registration.
One wait, not two. A refused re-registration that comes with a Retry-After goes straight to a fresh registration once that wait has passed, instead of retrying the refresh first and waiting a second time.
jorijnvdgraaf released this