On Mon, 2009-02-23 at 13:11 -0500, Dale Worley wrote: > I've been looking at XECS-2202 (kludge: use Min-Expires: 3600 value in > 423 Subscription Too Brief response). The original purpose of that > change is to avoid a problem with some phones, in that whenever they > successfully subscribe to BLF information, they use the expiration they > receive as the expiration they will request when they renew the > subscription. Since sipX gives less expiration time than requested for > most subscriptions (in order to ensure that resubscribe times are evenly > distributed), this causes the phone's requested expiration time to > shrink until it gets to the minimum that the sipX BLF server will > accept. Currently, that minimum is 32 seconds, which is too small for a > large number of phones to use, as it will overload the server. > > The change currently documented in the issue is to raise the minimum > time to 3600 seconds (1 hour), so that when a phone "ratchets down", it > will stop at 3600 seconds, which is a reasonable resubscribe interval. > The idea is that this is a temporary change until we can get the phone > manufacturers to correct their products. > > After thinking about this, I think a better strategy would be to: (1) > change the new minimum to 1800 seconds (30 minutes), and (2) make this > change permanent. > > My thinking is that we do not want phones, under any circumstances, > subscribing to any sipX server with sort subscriptions. (Requested > subscription time of 0 (that is, a polling request) is always allowed.) > 1800 seconds is a reasonable lower limit. 1800 seconds is significantly > smaller than the conventional default (3600 seconds), ensuring that > devices do not accidentally become unable to subscribe, and also > ensuring that the "resubscribe spread" algorithm has a wide range to > work with (1800 to 3600 seconds).
Good idea. +1 _______________________________________________ sipx-users mailing list sipx-users@list.sipfoundry.org List Archive: http://list.sipfoundry.org/archive/sipx-users Unsubscribe: http://list.sipfoundry.org/mailman/listinfo/sipx-users
