Appendix B. IPv6 Header Format
Although this specific material is not tested on the ROUTE exam, it might help you gain a better understanding of the structure of IPv6.
The IPv6 header is similar to the IPv4 header. The largest changes have to do with the larger addresses, aligning fields to 64-bit boundaries, and moving fragmentation to an extension header.
The fields are
• Version: 6.
• Priority: Similar to DSCP in version 4, this 8-bit field describes relative priority.
• Flow: 20-bit flow label enables tagging in a manner similar to MPLS.
• Length: The length of the data in the packet.
• Next Header: Indicates how the bits after the IP header should be interpreted. Can indicate TCP or UDP, or it can show an extension header.