What Type of Rhythm Makes an English Sonnet?

What type of rhythm makes an English sonnet?
How many beats per line does this beast use?
While snooty teachers have this in their bonnet,
For most the application’s somewhat loose.

To start, how many beats per line are there?
Default is ten, but you can go uneven:
Five feet of unstressed-stressed beats in a pair,
That’s ten. Add unstressed beat to end, eleven.

“That’s ten” above, it’s really two stressed beats.
Yet that’s allowed, ask Shakespeare or ask Keats.
But going nine or twelve or else defeats
The sonnet line, and meter quite unseats.

The rhyme scheme: a b a b, c d c d,
Then e f e f, followed by g g.

***

Rhythm pattern for the poem above:

(u = unstressed syllable, S = stressed syllable)

uS uS uS uS uS u
uS uS uS uS uS
uS uS uS uS uS u
uS uS uS uS uS

uS uS uS uS uS
uS uS uS uS uS u
uS uS uS uS uS
SS uS uS uS uS u

SS uS uS uS uS
uS uS uS uS uS
uS uS uS uS uS
uS uS uS uS uS

uS uS uS uS uS u
uS uS uS uS uS