fragmentation

Hi all, i get below result when i do sniffing. from what i read, frag caused by MTU size but which device caused this? is it fortigate itself, switch or server? do we need to standardize mtu size for mentioned devices? this problem cost me intermittent snmp but show no timed out when pinging. 52.594763 X.X.X.X.161 -> X.X.X.X.64243: udp 8270 (frag 60968:1480@0+) 52.594768 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:1480@1480+) 52.594786 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:1480@2960+) 52.594800 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:1480@4440+) 52.594803 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:880@5920+) 52.594820 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:1478@6800) 52.594832 X.X.X.X.161 -> X.X.X.X.64243: udp 8270 (frag 60968:1480@0+) 52.594834 X.X.X.X.161 -> X.X.X.X.64243: udp 8270 (frag 60968:1480@0+) 52.594836 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:1480@1480+) 52.594838 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:1480@1480+) 52.594840 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:1480@2960+) 52.594841 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:1480@2960+) 52.594843 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:1480@4440+) 52.594845 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:1480@4440+) 52.594846 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:1480@5920+) 52.594848 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:1480@5920+) 52.594850 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:878@7400) 52.594851 X.X.X.X -> X.X.X.X: ip-proto-17 (frag 60968:878@7400)