Visual RFC.
ALL RFCs / RFC 8200
Read the RFC ↗
RFC 8200 / MECHANISMS

Addresses identify interfaces

01

IPv6 expands addresses to 128 bits and supports unicast, multicast, and anycast delivery.

Related RFCs and changes

“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.

DIAGRAM§ 1 ↗
RFC 8200 · § 1EXAMPLE
3 / 3
Addresses identify interfacesA source sends to a single interface, a multicast group, then one member of an anycast set.128-bit addresses · delivery modelssourceone interfacemulticast groupunicastmulticastanycast → oneAnycast reaches one member, not the whole set
03
Select one member of a set.

Routing determines which anycast member receives the packet; it is not delivery to every member.

Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references
KEY POINT

An address names an interface or a set of interfaces.

  • IPv6 addresses are 128 bits, compared with IPv4’s 32 bits.
  • Unicast selects one interface; multicast reaches a group; anycast reaches one member of a set.
  • Detailed address formats and scopes belong to RFC 4291.
DETAILS

The drawing uses documentation addresses. It does not imply that every group member receives an anycast packet.

Read the RFC section ↗

Diagrams simplify the RFC. Read the linked sections for complete requirements.

Privacy
All chapters in this RFC
  1. Addresses identify interfaces
  2. Read the fixed IPv6 header
  3. Follow the next header chain
  4. Fit packets to the path
  5. Reassemble source fragments
  6. Forward with explicit limits
RFC 9700 / CHAPTERS

Chapters

For full details, tables, algorithms, and exceptions, read the original RFC.

RFC status and corrections ↗