You're viewing the documentation for the experimental version of Vagrant (the 1.x series). The current stable series is 1.0.x and the documentation can be found here. You can learn more about the Vagrant versioning scheme here.
Configuration key: config.ssh.timeout
Default value: 10
This is the timeout that Vagrant will use when attemping to make any SSH connection. Despite hitting this timeout, Vagrant does attempt to retry connections, but eventually if the timeout is continually reached, an error will be shown.