The Armada was a huge fleet of mind-bogglingly colossal floating Machines that formed a defense ring at the cliffs surrounding 01, the Machine City. Very large and appearing crab-like, they were armed with several cannons that shot bursts of Tow Bombs.
The Armada mostly lay dormant on the cliff at the edge of 01. When activated, they burst seem to burst out of cocoon-like housings and assemble for defense.
Neo and Trinity were confronted by the Armada as they flew the Logos to 01. The Armada, acting in coordination, immediately launched an enormous barrage of tow bombs at the Logos, Neo was able to stop a large number of the bombs allowing the ship to continue it's flight to 01 but the sheer number of bombs and Sentinels that attacked from the rear proved to be too much for Neo's power, forcing Trinity to fly above the cloud cover to shake them.