Ames is the name of the Urbit network and the vane that communicates over it. It's an encrypted peer-to-peer network composed of instances of the Arvo operating system. Each galaxy, star, planet, moon, and comet communicates over the network utilizing the Ames protocol.
Your ship upgrades itself with OTA updates via communication over Ames. The web interface, Landscape, of ships can be accessed by typing
sampel-palnet.arvo.network into a browser, where
sampel-palnet is the name of your ship.
Network continuity occasionally needs to be broken, either at an individual level to fix networking issues or at a network-wide level to update Arvo beyond what OTA updates are capable of doing. These events are called breaches.