Overview
This lecture covers the limitations of IPv4 addressing, introduces IPv6 as a solution, explains IPv6 address structure and compression, and discusses transition methods between IPv4 and IPv6 networks.
The Limitations of IPv4
- IPv4 supports only 4.29 billion unique addresses, but over 20 billion devices are connected to the internet.
- Network Address Translation (NAT) is used to extend IPv4 usability by allowing multiple devices to share one public address.
- IPv4 addresses have reached their maximum allocation; no new addresses can be assigned.
Introduction to IPv6
- IPv6 uses 128-bit addresses, allowing for a vastly larger address space than IPv4.
- Every grain of sand on Earth could have 45 quintillion unique IPv6 addresses.
- IPv6 solves the address exhaustion problem of IPv4.
IPv6 Address Structure and Compression
- IPv6 addresses consist of eight groups of four hexadecimal digits, separated by colons.
- Each group represents 16 bits (two bytes or two octets).
- Leading zeros in each group can be omitted for readability.
- Consecutive groups of all zeros can be replaced by a double colon (::), but only once in an address.
- Examples were provided to demonstrate address compression.
IPv4 and IPv6 Coexistence & Transition Methods
- IPv4 and IPv6 are not directly compatible and require transition solutions.
- Transition methods include tunneling (e.g., 6to4, 4in6), dual stack (running both protocols on the same device), and translation.
- Tunneling methods (6to4, 4in6) are now rare due to increased native IPv6 support.
- Dual stack allows devices to use both IPv4 and IPv6 addresses/routing independently.
- NAT64 and DNS64 technologies translate between IPv4 and IPv6, allowing communication between devices on different protocols.
Key Terms & Definitions
- IPv4 — Internet Protocol version 4, using 32-bit addresses.
- IPv6 — Internet Protocol version 6, using 128-bit addresses.
- NAT (Network Address Translation) — Translates private internal addresses to a public address.
- 6to4 — Tunneling IPv6 traffic over IPv4 networks.
- Dual Stack — Devices run both IPv4 and IPv6 simultaneously.
- NAT64/DNS64 — Translating mechanisms that enable communication between IPv4 and IPv6 devices.
Action Items / Next Steps
- Review examples of IPv6 address compression rules.
- Study how NAT64 and DNS64 facilitate IPv4/IPv6 communication.
- Ensure understanding of dual stack configurations for practical networking environments.