Supported

RFC 5549 - Advertising IPv4 Network Layer Reachability Information with an IPv6 Next Hop

Every requirement this repository extracted from RFC 5549, the tests bound to it, and what a reader has verified about them. This summary is enrolled and gated by ./le rfc check.

Overview

Positive

what Ze has

Tested both ways50.0%3 of 6 binding obligations

a positive test proves Ze does what the requirement demands and a negative one proves it refuses what the requirement forbids

One polarity plus reason50.0%3 of 6 binding obligations

the requirement admits no counter-case, so one polarity plus a recorded reason is the whole proof available for it

One polarity, unexcused0.0%0 of 6 binding obligations

one direction is tested, the other is neither tested nor excused, and nothing states which

No test at all0.0%0 of 6 binding obligations

no test carries the requirement id, whether or not a gap states why

Proven by a recorded break0.0%0 of 17 tagged units

a red was observed once under a recorded procedure, and the unit, the claim and the producer it rested on still hash to what was recorded. The break is not re-run. A test pair is not a proof until one has been observed

Neutral

measures that are neither good news nor bad

Gated MUSTs6of 9 this summary declares

MUST-level requirements the gate HOLDS. A population, not a result: the shares beside it are what says how Ze stands

Out of scope0of 6 gated MUSTs

a {not-applicable} annotation says the obligation does not bind Ze. Scope, not coverage: it is in no share below

The 4 shares marked as a part above are the whole of the 6 obligations that bind Ze: they add to 100%. Proven by a recorded break is a share of TAGGED UNITS, a different population, so it is not one of them.

How to read the colors

A color names what the measure MEANS, not how well Ze scores on it. Green is a good outcome at any value, red is a bad one, and neither a population nor a scope count is an outcome, so both take no color. The number under the label is what says how far Ze has got.

Card	Tone here	Why that color
Gated MUSTs	neutral	no color: a population is a scale, and a larger one is neither good news nor bad. It is the accounting total
Out of scope	neutral	no color: an obligation that never bound Ze is neither an achievement nor a failure, and counting it either way would be a claim
Tested both ways	ok	green at every value: a test pair is the outcome this gate exists to produce, and the share under the label is what says how far Ze has got
One polarity plus reason	ok	green at every value: where no counter-case exists, one polarity IS the complete answer, and a recorded reason is what the gate demands beside it
One polarity, unexcused	ok	green at zero, RED above it: half a proof with no reason for the other half
No test at all	ok	green at zero, RED above it: a binding obligation nothing exercises is a claim with nothing behind it, whether or not a reason is stated
Proven by a recorded break	ok	green at every value: an observed break is the outcome the discrimination gate exists to produce. The denominator is TAGGED UNITS, not obligations, so this share is not one of the parts above
Audit verdicts	warn	RED on the first weak, wrong or unimplemented verdict, amber while a verdict is no longer current or a gated MUST is unjudged, green when every one is judged sound and current

At a glance

Field	Value
Public status	Supported
Enrolment	Enrolled
Requirements	9
Gated MUST-level	6
Obligations that bind Ze	6
Not applicable, so out of scope	0
Declared gaps	0
Gated with no test	0
Nightly-only evidence	0
Test tags	17
Tagged units	17
Recorded audit verdicts	0
Discrimination records	0
Summary	`rfc/short/rfc5549.md`
Requirement shard	`rfc/requirements/rfc5549.md`
RFC text	`rfc/full/rfc5549.txt`

Enrolment

Enrolled: Advertising IPv4 NLRI with an IPv6 Next Hop (legacy encoding, obsoleted by RFC 8950 which ze implements): six MUST-level requirements, all met by the shared extended-next-hop implementation. 4-1 (cross-family IPv6 next-hop honored only when the extended-next-hop capability is negotiated), 3-1 (a 16- or 32-octet next-hop is decoded as IPv6), and 4-4 (do not use a cross-family next-hop without the negotiated capability) carry positive+negative tags. 4-2 (use the RFC 5492 capability mechanism), 4-3 (capability code 5), and 5-1 (do not rewrite a reflected next-hop) are {single-polarity: positive}. Tags added alongside the sibling RFC 8950 tags on internal/core/bgp/capability, internal/core/bgp/attribute, and internal/component/bgp/reactor tests.

What the public ledger says

Status: Supported

What the ledger says is covered:

Backward-compatible parser for the older format superseded by RFC 8950.

What the ledger says remains:

Main public claim uses RFC 8950.

Coverage

Bucket	Count	What it counts
Positive and negative tests	3	one part of the gated population
Annotated instead of tested	3	one part of the gated population
One polarity only	0	one part of the gated population
No test and no annotation	0	one part of the gated population
Evidence that runs nightly only	0	an overlay: each of these is also counted by the part it falls in
Gated MUST-level requirements	6	every gated MUST falls in exactly one bucket above

Positive and negative tests (3): RFC5549-4-1, RFC5549-3-1, RFC5549-4-4

Annotated instead of tested (3): RFC5549-4-2, RFC5549-4-3, RFC5549-5-1

Requirements

Requirement	Level	Section	Tests
`RFC5549-4-1`	A BGP speaker MUST only advertise IPv4 or VPN-IPv4 NLRI with an IPv6 Next Hop if it has ascertained via Capability Advertisement that the peer supports Extended Next Hop Encoding for the relevant AFI/SAFI pair (§4)
	MUST	4 - Use of BGP Capability Advertisement	positive`unit/verifyTestCanUseNextHopFor_ExtendedNH` positive`unit/verifyTestNegotiateExtendedNextHop` negative`unit/verifyTestCanUseNextHopFor_CrossFamilyNoCap` negative`unit/verifyTestNegotiateExtendedNextHopMismatch`
`RFC5549-4-2`	A BGP speaker that wishes to advertise an IPv6 Next Hop for IPv4 or VPN-IPv4 NLRI MUST use the Capability Advertisement procedures defined in RFC 5492 (§4)
	MUST	4 - Use of BGP Capability Advertisement	positive`unit/verifyTestExtendedNextHopCapability` positive`unit/verifyTestExtendedNextHopRoundTrip` negative`no test`no negative test {single-polarity}: ze advertises and parses the Extended Next Hop Encoding capability exclusively through the RFC 5492 capability TLV framework (internal/core/bgp/capability/capability.go:644 WriteTo, :667 parseExtendedNextHop). There is no non-RFC-5492 signalling path in ze, so no wrong-procedure case exists to assert as a negative; the peer-support-not-ascertained negative is covered by RFC5549-4-1
`RFC5549-4-3`	The Capability Code field MUST be set to 5 (Extended Next Hop Encoding) (§4)
	MUST	4 - Use of BGP Capability Advertisement	positive`unit/verifyTestCapabilityCodeConstants` positive`unit/verifyTestExtendedNextHopCapability` positive`unit/verifyTestExtendedNextHopRoundTrip` negative`no test`no negative test {single-polarity}: the Extended Next Hop Encoding capability code is the fixed constant CodeExtendedNextHop = 5 (internal/core/bgp/capability/capability.go:70); Code() returns it (capability.go:640) and WriteTo emits it (capability.go:646). The code has no alternate-value code path, so there is no wrong-code case to reject as a negative
`RFC5549-3-1`	The BGP speaker receiving the advertisement MUST use the Length of Next Hop Address field to determine which network-layer protocol the next hop address belongs to (§3)
	MUST	3	positive`unit/verifyTestParseMPReachNLRI_ExtendedNextHop` positive`unit/verifyTestParseMPReachNLRI_ExtendedNextHop_DualStack` positive`unit/verifyTestParseMPReachNLRI_ExtendedNextHop_VPN` negative`unit/verifyTestParseMPReachNLRI_InvalidNextHopLength`
`RFC5549-5-1`	When a next hop address needs to be passed along unchanged (e.g., Route Reflector), its encoding MUST NOT be changed (§5)
	MUST NOT	5 - Operations	positive`unit/verifyTestReactorForwardRRPreservesExtendedNextHop` negative`no test`no negative test {single-polarity}: on the reflection path ze rewrites the next-hop only under an explicit next-hop-self/explicit override (nhMode != nhModeNone); the default nhModeNone leaves the next-hop untouched (internal/component/bgp/reactor/peer_forward_facts.go:226) and the MP re-encode changes an attribute only when the NLRI framing differs between encoding contexts (internal/component/bgp/reactor/forward_body.go:217), so a reflected next-hop is carried verbatim and there is no ze code path that rewrites an unchanged-passthrough next-hop to assert as a negative. The positive is proven byte-identical in TestReactorForwardRRPreservesExtendedNextHop
`RFC5549-4-4`	MUST NOT send IPv6 Next Hop for IPv4 NLRI to peers that have not advertised Extended Next Hop Encoding capability (§4, Compatibility)
	MUST NOT	4 - Use of BGP Capability Advertisement	positive`unit/verifyTestCanUseNextHopFor_ExtendedNH` negative`unit/verifyTestCanUseNextHopFor_CrossFamilyNoCap` negative`unit/verifyTestCanUseNextHopFor_NilSendCtx`
`RFC5549-5-2`	By default, if a BGP session is running over IPvx, the next hop address SHOULD be specified as an IPvx address (§5)
	SHOULD	5 - Operations	positive`no test`no positive test negative`no test`no negative test
`RFC5549-4-5`	The Extended Next Hop Encoding capability MAY be dynamically updated through the Dynamic Capability capability (§4)
	MAY	4 - Use of BGP Capability Advertisement	positive`no test`no positive test negative`no test`no negative test
`RFC5549-5-3`	The default next-hop-address-family behavior may be overridden by policy (§5)
	MAY	5 - Operations	positive`no test`no positive test negative`no test`no negative test

Gaps and untested MUSTs

RFC 5549 declares no gap, and every gated MUST it carries has a test bound to it.

Proof state

A tagged unit reads unproven where no discrimination record exists for it: nothing in this tree has been observed to break it, so the claim its tag makes is unproven.

`RFC5549-4-1`

A BGP speaker MUST only advertise IPv4 or VPN-IPv4 NLRI with an IPv6 Next Hop if it has ascertained via Capability Advertisement that the peer supports Extended Next Hop Encoding for the relevant AFI/SAFI pair (§4)