A. Below is the specification for the header format of IPv6:
| Version |
Traffic Class |
Flow Label |
| Payload Length |
Next Header |
Hop Limit |
| Source Address |
| Destination Address |
Version - 4-bit Internet Protocol version number.
Traffic Class - 8-bit traffic class field
Flow Label - 20-bit flow label
Payload Length -16-bit unsigned integer. Length of the IPv6 payload,
i.e., the rest of the packet following this IPv6 header, in octets. (Note that
any present are considered part of the payload, i.e., included in the length
count.)
Next Header - 8-bit selector. Identifies the type of header immediately
following the IPv6 header. Uses the same values as the IPv4 Protocol field
[RFC-1700 et seq.].
Hop Limit - 8-bit unsigned integer. Decremented by 1 by each node that
forwards the packet. The packet is discarded if Hop Limit is decremented to
zero.
Source Address - 128-bit address of the originator of the packet.
Destination Address - 128-bit address of the intended recipient of the
packet (possibly not the ultimate recipient, if a Routing header is
present).
Notice that the IPv6 header has far less fields than the IPv4 header and
IPv6 introduces a number of extension headers as defined in RFC
2460.