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Introduction to IPv6 (Addressing the Future)

Networking Fundamentals: The 0 to Hero Guide

Lesson 40: Introduction to IPv6 (Addressing the Future)

The exponential growth of the internet led to the depletion of available public IPv4 addresses. IPv6 (Internet Protocol version 6) was developed to solve this scaling problem.

Key Differences from IPv4

  1. Address Size: IPv6 uses 128 bits (compared to IPv4's 32 bits).
  2. Address Space: This creates $3.4 imes 10^{38}$ possible addresses, virtually limitless.

IPv6 Address Format

IPv6 addresses are written as eight groups of four hexadecimal digits, separated by colons (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334).

IPv6 Compression Rules:

IPv6 addresses can be simplified using two rules:

  1. Omit Leading Zeros: Zeros at the start of a 4-digit block can be dropped (e.g., 0db8 becomes db8).
  2. Double Colon (::): A single sequence of consecutive blocks of zeros can be replaced by a double colon (::). This can only be done once per address.

Example Compression: Original: 2001:0db8:0000:0000:0000:130e:0000:1400 Compressed: 2001:db8::130e:0:1400

Addressing Types

  • Global Unicast: Publicly routable addresses (like public IPv4).
  • Link Local: Similar to APIPA. Used for communication only on the local link. Every IPv6 device automatically configures one (starting with FE80::).
  • Multicast: Used for one-to-many communication.

Transition: While IPv6 deployment is ongoing, most organizations run Dual Stack networks, supporting both IPv4 and IPv6 simultaneously.