IPv6 Network Techniques and Protocols

Introduction to IPv6

• IPv6 updates many techniques used in IPv4 for modern networking.
• Contains a new version of DHCP known as DHCPv6 for IP address assignment.

DHCPv6

• Uses similar processes as IPv4 DHCP for assigning IP addresses.
• Supports redundant DHCP servers, suitable for enterprise use.
• Managed by DHCP administrators.

Stateless Addressing in IPv6

• IPv6 can assign an IP address to itself, termed as "stateless addressing."
• No DHCP server is needed for this process.
• No need to track IP or MAC addresses.
• No lease time involved, IP addresses are retained indefinitely.

Neighbor Discovery Protocol (NDP)

• Essential for IPv6 stateless addressing and other functions.
• Unlike IPv4's ARP, NDP does not use broadcasts but multicasts, making communication more efficient.

Stateless Address Auto-Configuration (SLAAC)

• Allows devices to assign their own IPv6 address without a DHCP server.
• Device creates its own IP address autonomously.

Duplicate Address Detection (DAD)

• Ensures no duplicate IP addresses are present on the network, a key feature of IPv6.

Router Discovery with NDP

• NDP is used to discover routers using router solicitation and router advertisement.
• Devices send a multicast solicitation to find routers.
• Routers respond with advertisements and can send unsolicited RA messages to inform devices on the network of their presence.

Router Advertisements

• Provide details about the local subnet including:
  • Prefix values and lengths.
  • DNS server configurations.
  • Additional IPv6 settings.

SLAAC Process

1. Determine Local Subnet: Device uses NDP to ask a router via router solicitation about the local subnet.
2. Router Response: Router replies with a router advertisement containing subnet information, typically a 64-bit prefix.
3. Create Interface ID:
   • Devices can use a modified MAC address or randomize to generate the last 64 bits of the address.
   • FFFE is inserted in the middle of the MAC-derived address.
4. Address Uniqueness: DAD checks to ensure the IP address is unique on the network.

Outcome

• The device receives a unique, fully routable IPv6 address.