Halo Space Station Evolved

When does each round take place, IC?
Where is the system in which the rounds take place IC?

Each round takes place in an outer colony system, with the name being randomly chosen from a list of possibilities. Some examples would be Eridanus, or Epsilon Indi. The rounds take place during the first months of the Human-Covenant war. The insurrection is still the main threat, and the war itself is still kept secret. Most ordinary people would probably believe the Covenant to be insurrectionists.