The keeper presides over the cabmen's shelter under Loop Line Bridge where Stephen and Bloom go around 1am. after Stephen's fight with Private Carr (in "Eumaeus"). There is a rumor that he is Skin-the-Goat, the get-a-way driver from the Phoenix Park murders. The rumor is not true in real life (though Skin-the-Goat was employed as a night watchman after he got out in 1902) and is probably not true in the context of the book. The keeper gets going on nationalistic Irish talk after awhile, and it reminds Bloom of the citizen.
As regards the Odyssey, the keeper corresponds to Eumaeus, the old swineherd that takes Odysseus into his hut when he first returns home. It is where Odysseus first meets Telemachus when he returns to Ithaca.