What does buddie cause the narrator to remember?

The narrator, Billy Colman, comes home from work feeling very good. He sees several dogs fighting one dog, an old redbone hound. But the hound is defiant and fends off several attackers. Billy is shaken; he remembers a time when an old hound such as this one had sacrificed its life for him. Billy scares off the other dogs and calms down the dog. It is starving, has apparently traveled a great distance, and wears a leather collar with the name "Buddie" childishly scratched in it. Billy takes him home, feeds him and bathes him. The next night, Billy tearfully lets him go on his way. Billy wonders what displaced the hound from the country, but knows the hound will not give up on its way to its destination. It stirs up memories of Billy's childhood, his two red hounds, love, devotion, and death. He leaves his gate open in case the hound returns, then builds a fire inside. He examines two beautiful cups, one large and one small, and thinks about his childhood.