This is the Attrition (team deathmatch style) game type on the "Fracture" map in the Titanfall beta.

To have a chance to play the Titanfall beta for yourself, be sure to sign up here as the beta begins today, February 14. The beta will run until February 18 at 6PM (PT).

There was also a fairly long tutorial video showing you what every player in the beta will go through upon first firing up the game. There was also another Attrition round on Angel City that you should check out!