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IPv6 Multicast Decoder

The IPv6 multicast scope decoder is the front-door tool for the v3.6.0 multicast theme. It accepts any IPv6 address in the FF00::/8 multicast range and decodes it into:

  • Scope (1..15) and human-readable name (interface-local, link-local, admin-local, site-local, organization-local, global, or reserved) per RFC 4291 §2.7 and RFC 7346.
  • Flags (4 bits, layout 0RPT) with booleans for transient (T), prefix_based (P, RFC 3306), and embedded_rp (R, RFC 3956).
  • Scheme hint — one of well-known, transient, ssm, embedded-rp, or reserved.
  • Group ID — the lower 112 bits as a 28-character hex string.
  • Well-known group lookup — for the small set of named groups that ship with this tool (FF02::1, FF02::2, FF02::5/6 OSPF, FF02::9 RIP, FF02::a EIGRP, FF02::d All-PIM, FF02::16 MLDv2, FF05::101 NTP, plus the FF02::1:FF**:**** Solicited-Node family).
  • Deep-link to the per-scheme tool (the SSM and embedded-RP drawers ship in v3.6.0 T3 and T4 respectively).

Examples

Well-known group (All Nodes)

Input: FF02::1

Field Value
Scope 2 (link-local)
Flags 0b0000 (R=0 P=0 T=0)
Scheme well-known
Well-known All Nodes Address (RFC 4291)
Detail route none

SSM group (RFC 3306)

Input: FF3E::1234:5678

Field Value
Scope 14 (global)
Flags 0b0011 (R=0 P=1 T=1)
Scheme ssm
Well-known not matched
Detail route /ipv6/ssm

The P flag indicates a prefix-based / SSM group; the decoder offers a deep-link to the SSM tool drawer.

Embedded-RP group (RFC 3956)

Input: FF7E:140:2001:db8:cafe::1234

Field Value
Scope 14 (global)
Flags 0b0111 (R=1 P=1 T=1)
Scheme embedded-rp
Detail route /ipv6/embedded-rp

The R flag (set together with P+T) signals an embedded-RP group; the decoder deep-links to the embedded-RP tool.

Reserved scope

Input: FF00::1

Field Value
Scope 0 (reserved)
Scheme well-known (no registry match)

Scope 0 is reserved per RFC 4291 §2.7. The decoder still returns the canonical address and group ID for inspection.

REST API

POST /api/v1/multicast6 — see the OpenAPI spec for the full schema and worked examples for each scheme.

Shareable URLs

The decoder participates in the standard shareable-URL pattern: ?multicast6_input=FF02::1 on the IPv6 tab pre-fills the input and runs the decoder on page load.