While I'm not sure if the memory consumption has anything to do with your IP devices per se, its probably worthwhile to schedule (if possible) programmed reboot resource recovery.
"Memory Consumption Threshold
If the amount of free memory becomes less than
10 MB, a minor log is generated and a minor alarm is generated. The alarm is generated to notify the system maintainer that the system should be rebooted. Under normal circumstances, the system should remain up for 2 to 4 days after the alarm is generated. If configured, the system will be reset at the next programmed resource recovery reboot time.
5 MB, a major log is generated and a major alarm is generated. A schedule reboot should be programmed to reboot the system at the end of the day.
2 MB a critical log is generated and a critical alarm is raised on the system. The system resets immediately."
"Programmed Reboot Resource Recovery ON/OFF - Turns the programmed reboot on and off. If enabled, a software-controlled reboot will occur at the next occurrence of the specified time ONLY if the available memory threshold has been reached or if a non-critical resource failure occurs. Alarms are raised (Memory Consumption, Memory Fragmentation, Stale Tasks or Memory Avail) and Maintenance Logs generated. See Resource Monitoring for threshold details. Critical system resources may deteriorate to the point where the system performs a software-controlled reboot on its own, before the scheduled reboot time. If this occurs, the reason for the reboot is saved in the "panic" area of the Maintenance Log for the Memory Avail alarm. System Memory Consumption, System Memory Fragmentation and Stale System Tasks generate alarms and maintenance logs at the time of the resource failure."