Hi!

I have integrated OpenSER as a dedicated presence server in an ims network and I'm somewhat suffering from the delays the traversal of the ims core causes. Here's whats happening: Upon subscription the presence module sends a 202 Accepted (actually named OK, cosmetic bug?). At almost the same instant it also sends the first, in-dialog notify. What happens later is that sometimes the notify arrives before the ok. When this happens the client (on top of jain-sip) cannot identify the subscription dialog for the notification. It does not treat it correctly and does not respond OK to it. The absence of the response results in a timeout and the presence server invalidates the subscription.

Now, to solve this issue, would it be wise to introduce a parameter in the presence module which delays to transmission of the first notification to ease up the situation for the client.

Another solution is of course that the client simply inspects the local tag to prematurely identify the upcoming sip dialog for the subscription and then be able to treat the request properly. However, how does this stand against the standards?

I would be grateful for your input on the subject.

Leonard Broman