STUN

[treiher]

Schemas

• Fixed-size field systematization-binary-schemas#1
• Non-contiguous field systematization-binary-schemas#56

                   0                 1
                   2  3  4 5 6 7 8 9 0 1 2 3 4 5

                  +--+--+-+-+-+-+-+-+-+-+-+-+-+-+
                  |M |M |M|M|M|C|M|M|M|C|M|M|M|M|
                  |11|10|9|8|7|1|6|5|4|0|3|2|1|0|
                  +--+--+-+-+-+-+-+-+-+-+-+-+-+-+

           Figure 3: Format of STUN Message Type Field

Here the bits in the message type field are shown as most significant
(M11) through least significant (M0). M11 through M0 represent a 12-
bit encoding of the method. C1 and C0 represent a 2-bit encoding of
the class.

Specification

https://tools.ietf.org/html/rfc5389