How to deal with over-excitement around other dogs?

Hi,

I have a nine-month old BC. Whenever we see another dog on the horizon, he gets out of control, meaning he is focused on the other dog, wants to go to them and pulls the leash to do so and doesn't listen to me. In the interaction with other dogs he is a ball of energy that doesn't come to a standstill, which eventually exhausts other dogs until they turn aggressive, because he doesn't leave them alone.

  • What did I do wrong?
  • How can I get him to be more calm?
  • How can I get him to acknowledge boundaries, when other dogs signal their annoyance?

He also nips other dogs during play (herding behavior?). How can I get him to stop that and play with other dogs without using his teeth?

Any help is much appreciated :)