Trunk registration keepalive

Hi all.

My trunk registers with my provider just fine, I haven't had any trunk issues except one: It won't stay up for more than 3 days without requiring me to reload.

After 3 or 4 day of flawless operation the trunk goes down and people can't call in to me. I check and the trunk isn't registered, and doesnt read as registered with the provider. I do a reload and bam, registers fine. So it's like it registers once and then it times out at some point.

Is there a keepalive that I can set or some other way to keep the trunk from dropping off?

Thanks

-J