In which three ways is an IPv6 header simpler than an IPv4 header? (Choose three.)
Click on the arrows to vote for the correct answerA. B. C. D. E. F.
The correct answers are A, B, and C.
A) Unlike IPv4 headers, IPv6 headers have a fixed length: IPv6 headers are simpler than IPv4 headers because they have a fixed length of 40 bytes, while IPv4 headers vary in length from 20 to 60 bytes, depending on the options present. This fixed length simplifies packet processing and reduces the overhead of routing and forwarding packets.
B) IPv6 uses an extension header instead of the IPv4 Fragmentation field: IPv6 uses an extension header to carry information that was previously included in the IPv4 header. One such field is the Fragmentation field, which was used in IPv4 to enable packets to be fragmented into smaller pieces for transmission over networks with smaller Maximum Transmission Units (MTUs). In IPv6, this function is provided by the Fragmentation Extension Header, which is only used when fragmentation is required.
C) IPv6 headers eliminate the IPv4 Checksum field: IPv6 headers eliminate the Checksum field that was present in IPv4 headers. In IPv4, the Checksum field was used to detect errors in the packet header and payload. In IPv6, this function is performed by the upper-layer protocols, such as TCP and UDP, which have their own error-detection mechanisms. Eliminating the Checksum field simplifies packet processing and reduces overhead.
D) IPv6 headers use the Fragment Offset field in place of the IPv4 Fragmentation field: This statement is incorrect. In IPv6, the Fragmentation Extension Header is used in place of the IPv4 Fragmentation field, and the Fragment Offset field is used in both IPv4 and IPv6 to indicate the position of the fragment within the original packet.
E) IPv6 headers use a smaller Option field size than IPv4 headers: This statement is incorrect. In fact, IPv6 headers have no Options field, which was present in IPv4 headers and used for a variety of purposes, such as record route, timestamp, and security. In IPv6, this functionality is provided by extension headers.
F) IPv6 headers use a 4-bit TTL field, and IPv4 headers use an 8-bit TTL field: This statement is incorrect. In fact, IPv6 headers use a 8-bit Hop Limit field, which is similar to the TTL field in IPv4 headers. The Hop Limit field specifies the number of intermediate routers that a packet can traverse before being discarded, to prevent packets from looping indefinitely in the network.