I play on XBone, but the same applies. You need to either bridge your ISP modem/router, or put your net duma in your ISP routers DMZ to get an open NAT type. In my situation, I use UPnP and I also port forward the required ports for call of duty. For me I only play COD, and Blops3 plays like a dream compared to IW. IW is a shitshow.
and yes --- Wall---isp modem----netduma----all devices etc... oh and turn off wifi on your ISP modem
Check for nat type on your console, and not COD, COD nat type can show in-accurate at times