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BGP8 Prefix Checker

Validate an IPv8 CIDR and evaluate the draft's /16 minimum injectable prefix rule.

⚠ Proposed draft — not an adopted standard

BGP8 is the routing model described in draft-thain-ipv8. It has no IETF working-group endorsement and is not implemented by any BGP speaker. The "/16 minimum injectable prefix" rule is quoted from the draft; the exact operational semantics are ambiguous and this tool applies the literal reading (prefix length ≤ 16 is injectable).

Format: r.r.r.r.n.n.n.n/P, where P is 0–64.

About This Tool

The BGP8 Prefix Checker validates an IPv8 CIDR and evaluates it against the "/16 minimum injectable prefix" rule described in draft-thain-ipv8. It parses the 64-bit address, computes the network start and end, counts the covered host addresses, flags whether the prefix crosses the ASN/host boundary, and indicates whether the prefix would be acceptable under the literal reading of the draft's injectability rule. BGP8 is a proposal, not an adopted standard — this tool is purely educational.

How to Use

  1. Enter a CIDR in the form r.r.r.r.n.n.n.n/P where P is between 0 and 64
  2. Press Check to parse and evaluate
  3. Review the network start/end, host count, and ASN boundary indicator
  4. The "/16 rule" badge shows whether the prefix is short enough (≤ /16) per the draft's stated injectable minimum

Features

  • Validates IPv8 CIDR syntax (64-bit address + /0–/64 prefix length)
  • Computes network start, network end, and covered host count
  • Identifies whether the prefix spans the ASN ↔ host boundary
  • Evaluates the draft's /16 minimum injectable prefix rule (literal reading)
  • Large-integer host counts handled with BigInt for accuracy

Common Use Cases

  • Sanity-checking example BGP8 prefixes used in blog posts or discussions
  • Teaching how the ASN (/32) and host (/32) halves of an IPv8 address compose
  • Exploring the implications of the draft's injectable-minimum rule
  • Debugging reference implementations of draft-thain-ipv8 parsing

Technical Details

IPv8 addresses are 64 bits long. A CIDR prefix selects the leading P bits, where P is between 0 and 64. Host count is computed as 2^(64 − P).

ASN boundary: the first 32 bits of an IPv8 address encode an ASN routing prefix. A CIDR with P < 32 spans multiple ASNs; one with P ≥ 32 sits inside a single ASN.

/16 minimum injectable prefix rule: draft-thain-ipv8 states the global BGP8 routing table is bounded by a "/16 minimum injectable prefix rule" that prevents deaggregation. The draft's wording is ambiguous; this tool applies the literal reading — any prefix of length ≤ 16 is injectable; anything more specific is flagged. See the draft for context.

Caveat: No real BGP speaker implements BGP8. This tool exists for exploration and does not imply the rule is sensible or adoptable. See our IPv8 explainer for background on the criticism.