Describe what is included in the header portion of the IPv4 packet, and contrast that with the IPv6 header.

What will be an ideal response?

In IPv4, the first portion of the packet or the header that appears prior to the actual data carried in the packet is weighted down by optional information, such as packet fragmenting, authentication, or specialized security information. The IPv4 packet header also contains a checksum, which is a redundant check on the values contained within the header. The IPv6 header is streamlined to contain only vital information, such as the packet source and destination addresses. Optional information, such as for special security or routing information, is stored in one or more of six types of extension headers, which always are placed after the main header. The use of extension headers enables packets to be processed more efficiently for better network performance. This is because if no optional information is necessary, then the packet is not burdened with reserving empty space for unused information. On the other hand, extension headers enable an IPv6 packet to carry more sophisticated information as needed, such as for security.