I have twelve 1625 installed under a dual WAN router (Cisco RV-082) in balanced mode, since it is a Dual WAN router sometimes the IP you see is from from one ISP, sometimes from other.
The issue is: On default setup (after factory reset), I only set up the SIP registration information then I got "Registered" status and can make call or receive calls immediatly, but after 1 min idle all callers will get "The person you want to reach is not available" even when the "registered icon" remains black (registered), if they insist and call and call after 6 to 10 times continuesly the phone rings. If some one call again right after I hang it rings normally, but if it goes idle for more than 60 secs, callers will hear the "not available" message again, it seems to be going into a "sleep mode"
I figure out to check ON the Keep Alive option, it works better, but after 5-10 min it goes to "sleep", so I changed the Keep Alive Interval from 30 sec to 10 sec, now it goes to sleep after 30-40 min, next I change the Keep Alive Interval to 5 sec, it stay "awake" for hours, only 3 of 12 goes to sleep after 3 hours BUT people at the office where the SIP server is located reports heavy internet lags -maybe too much pings from the 12x 1625 to it?-
Is there anything I have to set being under a Dual WAN network to keep the 1625 "alive" or "awake"?