IPv4 header

The following fields are defined for the IP version 4 header, as described in [RFC791]:

$$\begin{tabular}{l\vert cccccccccccccccccccccccccccccccc\vert... ...2-33} \multicolumn{33}{l}{{\tt ip\_nexthdr}} \\ \end{tabular}$$

The definition of the ip_tos octet^2.4revised, and is now called the ``Differentiated Services field''. The corresponding definitions are described in section 2.13.2. Additional convenience fields for the traditional and now deprecated use of ip_tos are described in section 2.13.2.

Note that ip_src and ip_dst are of type ``IPv4 address''.

The following flags are used for handling IP fragments:

$$\begin{tabular}{\vert c\vert c\vert c\vert} \multicolumn{1}... ...ip\_RF} & {\tt ip\_DF} & {\tt ip\_MF} \\ \hline \end{tabular}$$