It has been revealed that Spec Ops on MW3 will have its very own matchmaking system and that it will also include a progressive ranking system.
One interesting part of Spec Ops will be the new Survival Mode, which will force the player to fight off and defend against waves of different kinds of enemies. A few of these enemies have already been touched-on by Infinity Ward's Creative Strategist, Robert Bowling. The player will have to fend against regular enemies, dogs, Juggernauts (in case you didn't already know, a Juggernaut is a regular enemy with added health) and Suicide Bombers. While speaking about the new Spec Ops mode, Bowling said that each enemy will have to be fought off using a different strategy.