Similarity
Both are used to control flow

Differences
Leaky Bucket

• Leaky bucket uses a queue to absorb a burst of requests & a constant set of requests are dequeued.
• If request overflows the queue capacity, the data is lost.

Leaky Token Bucket

• Think of N semaphores as tokens.
• Leaky Token Bucket algorithm accepts a request till a semaphore is available.
• If no token is available, the sender is blocked. So no data loss as such.