Pushkin is a 9 year old Persian, extremely sweet and mellow and last March we got our boxer Pepik who's now 13 months. They are very curious of each other but Pushkin runs away because Pepik is too rambunctious and scared Pushkin i think. The firsth three days afer we got Pepik, Pushkin wasn't happy and stopped eating. Unfortunately he got less attention in the beginning because i had to watch the puppy all the time. Now things calmed down, Pepik isn't allowed upstairs so Pushkin has a free zone there unless Pepik sneaks up unnoticed which happens once in a while. Sometimes that happens I can hear Pushkin vocalize a protest that sounds like "Oh no, not again! Take that annoying creature away from my view" And because Pepik knows he's not allowed to chase Pushkin or go upstairs he immediately retreats when i approach them. Pushkin doesn't come downstairs unless he knows Pepik is sleeping and then he dares to come and even sniff on our sleeping boxer. He probably feels that Pepik has occupied his territory which is partly true. Pushkin is just too sweet,he doesn't hiss or use his claws or anything at all, just runs away.
But I hope and think they can become good friends when Pepik learns to be a bit easier which will probably take some more time. I have tried to make clear that Pushkin is a beloved part of our family and i'm convinced Pepik understood that much. But Pepik's play drive is tremendously strong, he gets overly excited.
Good luck with your puppy!