DiffServ Byte

Given that the TOS byte was rarely used, the IETF redefined it and in doing so created the DiffServ byte.

The DiffServ byte format is as follows:

The DiffServ codepoint value is six bits long, compared to the three-bit-long TOS byte’s precedence component. Given the increased bit length, DiffServ codepoints can range from 000000 (decimal 0) to 111111 (decimal 63).

Note:

By default, DiffServ codepoint mappings map exactly to the precedence component priorities of the original TOS byte specification.