Ok here are a few hints to try to improve your situation.
First of all, on most computers running windows you will have a software firewall.
This can be Microsoft firewall, or found in Microsoft security center of windows.
In most routers you also have a hardware firewall that by default should be enabled.
If you wish to use the hardware firewall of your router, and it is enabled.
Turn off your windows based firewall.
Set the security level of the hardware firewall in your router to medium.
Check in the router that Upnp mode is also enabled
Use google to find out what port numbers must be setup in your router when playing Bo3.
Get the IP address your router has assigned your machine ie: 192.168.0.X X being the number of your machine.
All devices connected to the router will be listed along with the IP the router assigned them, with the name of your computer beside it.
And can be found in the routers menu pages or status page.
Now look for the port forwarding section in your routers software firmware menus.
Input a name such as BO3 1
Then the IP the router gave your pc on the network.
Set the protocol the port uses UDP, TCP or Both, input the port number.
Click apply then set up a new name, putting the same ip address in, and the protocol type with the new port number used.
Do this till you have added all of the port addresses along with the protocols used and your Ip of your machine.
Exit the router once you have applied all of the settings.
Run BO3 and see if the lag problems have gone away.