The IPv6 header format is shown in Figure 13.1. Note that the basic IPv6 header is actually simpler than the corresponding IPv4 header. Part of the reason for the header’s simplicity is that detailed information is relegated to special extension headers that follow the main header.
The fields of the IPv6 header are as follows:
Version (4-bit)— Identifies the IP version number (in this case, version 6).
Traffic Class (8-bit)— Identifies the type of data enclosed in the datagram.
Flow Label (20-bit)— Designates the flow level (described in the preceding section).
Payload Length (16-bit)— Determines ...