A network engineer is analyzing protocol analyzer traces and configuration files during an IPv6 deployment. The engineer needs to verify the operational mechanics of the IPv6 base header and validate IPv6 address formatting rules. Which of the following statements correctly describe the characteristics of the IPv6 base header or valid IPv6 address compression mechanics? (Select TWO.)
- The Next Header field specifies the protocol type of the encapsulated payload or identifies an incoming extension header, serving a function equivalent to the IPv4 Protocol field.Answer
- BThe double-colon (::) shorthand notation can be used up to two times in a single IPv6 address provided each instance replaces distinct contiguous blocks of zeros.
- The Hop Limit field is an 8-bit field decremented by each router that forwards the packet, replacing the IPv4 Time to Live (TTL) field to prevent routing loops.Answer
- DThe IPv6 base header length varies dynamically between 20 bytes and 60 bytes depending on whether Traffic Class or Flow Label fields are populated.
Answer
The correct statements are that the Next Header field specifies the protocol type of the encapsulated payload or extension header (equivalent to the IPv4 Protocol field) and the Hop Limit field is decremented at each router hop to replace the IPv4 Time to Live (TTL) field.
The statements describing Next Header as the equivalent of IPv4 Protocol and Hop Limit as the 8-bit replacement for IPv4 TTL are technically correct. Next Header defines the encapsulated layer 4 payload or extension header, while Hop Limit is decremented by 1 at each router to stop loop propagation.
Step-by-Step Solution
Key Concept
IPv6 Header Fields and Compression Syntax Rules
Estimated Time:1m 30s