Question

Difficulty: Very hardIPv6 Addressing and Deployment

A network architect is designing an enterprise IPv6 deployment and reviewing address allocation strategies and autoconfiguration modes. Match each IPv6 deployment mechanism or address scope on the left with its exact functional operation and protocol behavior on the right.

  • Stateless Address Autoconfiguration (SLAAC) with Stateless DHCPv6Uses Router Advertisements with M=0 and O=1 flags to supply the network prefix via SLAAC while directing endpoints to obtain auxiliary options (such as DNS) from DHCPv6.
  • Stateful DHCPv6 DeploymentUses Router Advertisements with M=1 and O=1 flags to instruct endpoints to obtain both their IPv6 address lease and auxiliary configuration parameters directly from a DHCPv6 server.
  • Link-Local Unicast AddressingMandatory fe80::/10 block address utilized exclusively for single-link neighbor discovery, router adjacencies, and local communication without multi-hop routing.
  • Unique Local Addressing (ULA)Uses the fc00::/7 prefix (typically implemented as fd00::/8) to provide globally unique, non-publicly routable IPv6 addressing across internal enterprise subnets.

Answer

SLAAC with Stateless DHCPv6 matches the configuration using RA flags M=0 and O=1; Stateful DHCPv6 Deployment matches the configuration using RA flags M=1 and O=1; Link-Local Unicast Addressing matches the fe80::/10 block for single-link communication and NDP; Unique Local Addressing matches the fc00::/7 block for non-public internal routed communication.
Each IPv6 mechanism is paired strictly according to standard RFC specifications: SLAAC with Stateless DHCPv6 relies on M=0 and O=1 RA flags; Stateful DHCPv6 requires M=1; Link-Local addressing uses the fe80::/10 prefix exclusively for local-link functions; and Unique Local Addresses utilize fc00::/7 for non-public internal routed communication.

Step-by-Step Solution

1
Analyze SLAAC with Stateless DHCPv6 flag settings.
Determined that M=0 delegates IP creation to SLAAC, while O=1 requests non-IP settings from DHCPv6.
Stateless DHCPv6 does not issue IP leases; it only supplies auxiliary options.
2
Analyze Stateful DHCPv6 flag settings.
Determined that M=1 instructs hosts to obtain IP address leases statefully from the DHCPv6 server.
Stateful operation centralizes address tracking and lease management.
3
Evaluate Link-Local addressing scope and purpose.
Associated fe80::/10 with mandatory single-link protocol operations.
Link-Local addresses are automatically assigned on all enabled interfaces and cannot cross routers.
4
Evaluate Unique Local Addressing scope and purpose.
Associated fc00::/7 (fd00::/8) with enterprise internal private routing.
ULAs function similarly to IPv4 RFC 1918 addresses within internal networks.

Key Concept

IPv6 Addressing Scopes and Neighbor Discovery RA Flag Autoconfiguration
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