Examkin

Question

Difficulty: MediumIPv6 Addressing and Deployment

A network engineer is documenting the IPv6 address allocation for an enterprise router interface. The fully expanded, uncompressed address assigned to the interface is 2001:0db8:0000:0042:0000:0000:0000:0007. According to RFC 5952 rules, what is the correctly compressed and canonicalized representation of this IPv6 address?

Answer: 2001:db8:0:42::7

Answer

2001:db8:0:42::7
According to RFC 5952 standards for IPv6 address canonicalization: 1) Leading zeros within each 16-bit field must be removed (0db8 -> db8, 0042 -> 42, 0007 -> 7). 2) A single all-zero field is written as 0. 3) The double-colon (::) must be used to compress the longest contiguous sequence of all-zero fields. In this address, the sequence of three zeros (0000:0000:0000) is longer than the single zero field, making 2001:db8:0:42::7 the only correct canonical compressed address.

Step-by-Step Solution

1
Suppress leading zeros in each 16-bit hexadecimal field (hextet).
2001:0db8 becomes 2001:db8; 0000 becomes 0; 0042 becomes 42; 0000:0000:0000 becomes 0:0:0; 0007 becomes 7. The intermediate string is 2001:db8:0:42:0:0:0:7.
RFC 5952 requires removing leading zeros within each hextet while preserving a single zero for any all-zero hextet.
2
Identify all contiguous sequences of all-zero hextets and select the longest sequence to compress using double-colon (::).
Sequence 1 is at index 3 (length 1: '0'). Sequence 2 is at indices 5-7 (length 3: '0:0:0'). The longer sequence (length 3) is replaced with '::'.
RFC 5952 specifies that double-colon (::) must replace the longest contiguous run of all-zero hextets. Shorter single-zero hextets must remain as a single '0'.
3
Combine the compressed sections into the final canonical IPv6 address.
2001:db8:0:42::7
Ensures full compliance with RFC 5952 formatting and lowercase hexadecimal standards.

Key Concept

RFC 5952 IPv6 Address Compression and Canonical Representation
Rate this question

Topics

IPv6 Addressing and Deployment

More questions from this topic