Read an IPv6 Address — TechKnowSurge

About this interactive

An IPv6 address is 128 bits. It is written in hexadecimal, where each digit stands for 4 bits (a nibble). Four hex digits make a hextet of 16 bits, and eight hextets, separated by colons, make the whole address. The RFCs recommend lowercase letters. Every bit doubles the number of possible addresses, so 128 bits give 2^128, about 3.4 × 10^38. The video says "10 to the 128th"; that is a slip. A power of ten would need ten choices in every position, like a decimal digit, and a bit has only two. IPv4's 32 bits give 2^32, about 4.3 billion addresses, and that shortage is why IPv6 exists. The prefix length works like CIDR in IPv4: /64 means the first 64 bits, the first four hextets, are the network part, and the last 64 bits are the host part. /64 is the standard for a network. A larger block handed to a site, such as a /48, covers the first three hextets. Two shorthand rules shorten an address. Leading zeros in a hextet can be dropped (0db8 becomes db8), but zeros after the first other digit stay (00a0 becomes a0, never a). And one run of all-zero hextets can be replaced by a double colon, once per address. To read a double colon, count the hextets that are written; the :: stands for however many it takes to make eight. That is also why it may appear only once: with two, nobody could tell how the hidden hextets are split. Type numbers in digits and hextets or addresses in hex, as each item asks. Capital letters do not matter. Anything you miss shows the answer and how to work it out. Seven of the nineteen items are drawn each run, so a second run is a different sheet.

What you'll learn

State the IPv6 address space correctly as 2^128 (about 3.4 × 10^38), because each of its 128 bits doubles the count, and compare it with IPv4's 32 bits and 2^32 addresses
Read the structure of an IPv6 address: 4 bits to a hex digit, four hex digits and 16 bits to a hextet, eight hextets to the 128-bit address
Use the prefix length to split an address into its network and host parts, for the standard /64 and for a /48
Apply the two shorthand rules: drop only the leading zeros in a hextet, and count how many all-zero hextets the one double colon stands for

Aligned to

ISC2 CC

4.1 Understand network security

Cisco CCST Networking

2.3 Identify IPv6 addresses and prefix formats

CompTIA Network+

3.4 Given a scenario, implement IPv4 and IPv6 network services

Cisco CCNA

1.8 Configure and verify IPv6 addressing and prefix

Key terms

Hextet: A group of four hexadecimal digits in an IPv6 address; eight hextets separated by colons form a complete 128-bit IPv6 address.
Prefix Length: The number of consecutive 1-bits in a subnet mask, written after a slash (e.g., /24), that defines how many bits of an IP address represent the network portion versus the host portion. A /24 prefix means the first 24 bits identify the network, leaving 8 bits for host addresses.
Shorthand Notation: IPv6 address abbreviation rules that allow removal of leading zeros within hextets and replacement of one contiguous group of all-zero hextets with a double colon (::).
Leading Zero Suppression: An IPv6 compression rule that allows leading zeros within any 16-bit group to be omitted.
Double-Colon Notation: An IPv6 compression rule represented by '::' that replaces one or more consecutive all-zero 16-bit groups, usable only once per address.
Hexadecimal: A base-16 number system using digits 0–9 and letters A–F; each hex digit maps to exactly 4 bits, making it a compact shorthand for representing binary data.
Nibble: A group of exactly 4 bits, equivalent to one hexadecimal digit; two nibbles make up one byte.
IPv4: The fourth version of the Internet Protocol, using 32-bit addresses that provide approximately 4.3 billion unique addresses.

Topics

Ipv6 Hextet Prefix Length Shorthand Notation Interactive Fill In

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