Instructions
Log in to your router's configuration utility and click on the "WAN Setup" or similarly named option in the "Advanced" section of the main menu.
Select the "Open" option next to "NAT Filtering" and click the "Apply" button.
Click on the "UPnP" or "Universal Plug and Play" option in the "Advanced" section of the main menu and select the "Enable" or "Turn On" check box.
Click the "Apply" button to save your settings and then try playing "Call of Duty: Black Ops" on your PS3 again. Your lagging issues should now be solved. If the connection is still laggy, consider contacting your ISP (Internet Service Provider) about upgrading your Internet speed.