I'm a newbie and I've been studying range-request for byte serving. I found that server has to send byte-range from as this
Content-Range: bytes 734-1233/1234
The first-byte-pos value in a byte-range-spec gives the byte-offset of the first byte in a range. The last-byte-pos value gives the byte-offset of the last byte in the range; that is, the byte positions specified are inclusive. Byte offsets start at zero.
Applying this to the the examples in 4.2 Content-Range:
The following are examples of Content-Range values in which the selected representation contains a total of 1234 bytes: o The first 500 bytes: Content-Range: bytes 0-499/1234
Since the range is zero-based, 0 is the first byte and 499 is the 500th. So, 1233 is the final byte of a 1234-byte document.