Umbilical
From Halopedia, the Halo wiki
Umbilicals are corridors branching out from UNSC Orbital Defense Platforms that serve as docking points for other ships.
Cairo Station Umbilicals
During the First Battle of Earth, SPARTAN-117 cleared the portside Umbilicals enroute to the Covenant Bomb in Firing Control. This allowed Commander Miranda Keyes, Johnson, and her Flight Lieutenants to board the UNSC In Amber Clad.
