Overview
This lecture covers how IPv6 updates address assignment methods from IPv4, highlighting DHCPv6, stateless autoconfiguration, and the Neighbor Discovery Protocol (NDP).
DHCP in IPv6
- DHCPv6 assigns IPv6 addresses using a process similar to DHCP in IPv4.
- IPv6 DHCP servers support redundancy for enterprise environments.
- DHCP administrators manage both IPv4 and IPv6 DHCP servers.
Stateless Address Autoconfiguration (SLAAC/SLAC)
- IPv6 devices can assign addresses to themselves without a DHCP server, known as stateless addressing.
- Stateless addressing does not require lease times or address tracking.
- Devices use SLAAC to create their own unique IPv6 addresses.
Neighbor Discovery Protocol (NDP)
- NDP replaces ARP (Address Resolution Protocol) from IPv4 and operates using multicast instead of broadcast, making communication more efficient.
- NDP enables devices to find each other and discover routers on the local network.
- NDP facilitates router discovery using Router Solicitation (RS) and Router Advertisement (RA) messages.
- Routers can respond to solicitations or send unsolicited RA messages to inform devices of their presence.
IPv6 Address Formation & Duplicate Address Detection (DAD)
- Devices use NDP to determine the local subnet prefix via Router Advertisement (usually the first 64 bits of the address).
- The device generates an interface ID (last 64 bits) using a modified MAC address or a random value.
- DAD ensures no duplicate addresses exist on the network by checking the uniqueness of each generated IPv6 address.
Key Terms & Definitions
- DHCPv6 — Dynamic Host Configuration Protocol for IPv6 networks, used for automatic address assignment.
- Stateless Address Autoconfiguration (SLAAC/SLAC) — Method allowing devices to self-assign IPv6 addresses without DHCP.
- Neighbor Discovery Protocol (NDP) — Protocol for address resolution, device discovery, and router discovery in IPv6.
- Router Solicitation (RS) — IPv6 message sent by devices to discover routers on the network.
- Router Advertisement (RA) — IPv6 message sent by routers to inform devices of network configuration.
- Duplicate Address Detection (DAD) — Mechanism in NDP to prevent IP address conflicts in IPv6.
Action Items / Next Steps
- Review DHCPv6 and NDP operation processes.
- Study how SLAAC and DAD work in practice.
- Be able to explain the IPv6 address formation process.