Graynomad:
I asked because if the data is binary (and can therefore be any value) there's no way I know of to reliably detect a start of frame by just looking at received bytes.
Oh yeah of course it's impossible to know 100%, but being a 1 in 255 chance plus the checksum and other marker bytes, it's pretty safe.
Graynomad:
length (2 byte int)
Expecting a lot of data
Hey if they had made IP addresses more than 32 bits back in the day I wouldn't be paying 2 bucks a month for every site that uses SSL.
Extra byte, I figured why not (the alternative is 255 bytes). Even though the largest command I'll send here is 9 bytes.