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:
![](img/GUID-9B0008D3-092B-4542-B816-38135A5628A2-default.gif)
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.