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