The mage can control access to the Spirit Roads he creates to cross the Gauntlet, as described in Spirit Road. He can also choose to cross the Gauntlet on his own without creating a Spirit Road.
The mage can approve who can walk his Spirit Roads. This is an ability he simply has. He does not need to cast this spell to have the power over any Spirit Road he creates.
He does cast this spell to “step sideways” across the Gauntlet without the need for a Spirit Road. Doing so costs one Mana and the roll is modified by the Gauntlet’s Strength.
Mysterium Rote: Shadow Gate
With this rote, a Mysterium willworker can control who and what is permitted to cross through the roads he makes through the Gauntlet, or he can simply step through without the need for such a gateway.
Guardians of the Veil Rote: Dark Doorway
Guardians of the Veil use much the same magic in the pursuit of their work.