As part of any offensive operation the attacking force will set up a "support by fire" position to make life easier for the assaulting force. When people talk about "Fire and Maneuver" it is the "Support by Fire" position that provides the fire.
So if you wake up to the sound of your front door being kicked open by jackbooted thugs odds are there is already someone else covering your residence to make sure you don't get out alive to fight another day. Of course by then you are screwed anyways.
A support by fire position will be set up in the following manner.
1. Close enough to be effective, far enough to maintain some standoff. Obviously in thick forest the SBF has to be a lot closer than in high altitude desert.
2. Able to communicate with the assault element in multiple ways to ensure a proper "shift fire" and "life fire". The only thing more accurate than enemy fire is friendly fire.
3. Able to seal off 270 degrees of the objective and in coordination with an observer element (usually scouts or snipers) to cordon off the remaining 90 degrees. To visualize this, think of the objective (a house or camp) as the center of PacMan, and his open mouth is the "blind spot" that the SBF can't see. By shifting another element out to the extreme flank, they can have eyes on the blind spot from the SBF position. If in an urban environment the degrees change, but the principle stays the same, a main SBF with observers supporting the SBF which is in turn supporting an assault element.
Currently in the "War on a Noun" there are not a lot of active SBF operations as the preferred method is a soft raid. All that means is the SBF isn't shooting while the assault element goes in. They are still there, and still providing eyes on. This tactic is a lot like civilian LE agencies use for "The War on Certain Chemicals" to the point where I don't see any real differences.
Now I could get into machine gun math, about how long a SBF position can suppress an objective to give time for the assault element to get into place, but that isn't necessary. A few highly accurate rounds are just as effective at making someone keep their head down as multiple machine guns spraying ammo across the battlefield. If every time you stuck your head up it got buzzed by a bullet that would slow you down right? You can make SBF work with just about anything, it is an old tactic.
Now this is all part of a bigger operation. The flank security (or outer cordon) is isolating the objective, the SBF (or inner cordon) is denying the enemy the ability to move out of the objective, the assault element is going to conduct actions on the objective.