A giant ringed ship with beams...and moves? So...a mobile Knossos portal with guns? Guess you could flip the power on/off switch so you can decide whether to let shipping thru or not (would only work if normally set to off, if you left it on the node will stabilize to a point where the Knossos is no longer necessary).
But anyways I still think post-Capella the GTVA already had another Colossus either near completion or already halfway done. So they'd complete it, with modifications to deal with Shivan juggernauts better.