With IPHost Network Monitor you can run simple snmp requests against a Fortinet device in your network.
fgApSIPServices
fg Ap SIP Services
1.3.6.1.4.1.12356.101.10.106.3.1.3
Number of service requests (Subscribe, notify and Message) in this virtual domain processed by the SIP proxy since start-up
Back to FORTINET-FORTIGATE-MIB MIB page.
IPHost Network monitor allows you to monitor fgApSIPServices on Fortinet device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Fortinet WAN extenders right now.