Supported

RFC 7911 - Advertisement of Multiple Paths in BGP

Every requirement this repository extracted from RFC 7911, 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 ways88.9%8 of 9 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 reason11.1%1 of 9 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 9 binding obligations

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

No test at all0.0%0 of 9 binding obligations

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

Proven by a recorded break0.0%0 of 43 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 MUSTs9of 13 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 9 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 9 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	13
Gated MUST-level	9
Obligations that bind Ze	9
Not applicable, so out of scope	0
Declared gaps	0
Gated with no test	0
Nightly-only evidence	0
Test tags	43
Tagged units	43
Recorded audit verdicts	0
Discrimination records	0
Summary	`rfc/short/rfc7911.md`
Requirement shard	`rfc/requirements/rfc7911.md`
RFC text	`rfc/full/rfc7911.txt`

Enrolment

Enrolled: Advertisement of Multiple Paths in BGP (ADD-PATH): nine MUST-level requirements. Eight are met: 3-1 (a 4-octet Path Identifier is prepended to NLRI when ADD-PATH is negotiated), 4-1 (a single ADD-PATH capability instance lists all AFI/SAFIs), 5-1 and 5-2 (a path is sent only if the local speaker advertised Send/Both and the remote advertised Receive/Both), 5-3 (Path IDs are not added when ADD-PATH is not negotiated for the family), 5-4 (the RIB is keyed by prefix and Path ID and the egress encodes the Path ID), and 5-5 (a negotiated family's received NLRI is parsed with its 4-octet Path ID) carry positive+negative tags. 2-1 (the same prefix with different Path IDs is treated as different paths) is {single-polarity: positive}: the per-peer RIB key is (prefix, Path ID) by construction. 2-2 (a speaker re-advertising a path generates its own Path Identifier) is {gap}: ze preserves the ingress Path Identifier on re-advertisement rather than minting its own. Disclosed in the docs/features/rfc-status.md RFC 7911 row.

What the public ledger says

Status: Supported

What the ledger says is covered

Per-family send and receive modes, Path ID packing, NLRI path IDs where negotiated
a re-advertised route carries ze's own Path Identifier (RFC7911-2-2), assigned per ingress path in internal/component/bgp/reactor/forward_path_id.go and read by both the raw same-context forward and the re-encode, so an announcement and its withdraw leave under one value and two clients that chose one identifier for a prefix stay two paths at a third
tests bound per requirement in rfc/requirements/rfc7911.md.

What the ledger says remains:

Closed 2026-08-14: RFC7911-2-2. Until then ze relayed the ingress Path Identifier, so a route server merged two clients' paths for one prefix into one and lost a route.

Coverage

Bucket	Count	What it counts
Positive and negative tests	8	one part of the gated population
Annotated instead of tested	1	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	9	every gated MUST falls in exactly one bucket above

Positive and negative tests (8): RFC7911-2-2, RFC7911-3-1, RFC7911-4-1, RFC7911-5-1, RFC7911-5-2, RFC7911-5-3, RFC7911-5-4, RFC7911-5-5

Annotated instead of tested (1): RFC7911-2-1

Requirements

Requirement	Level	Section	Tests
`RFC7911-2-1`	Path Identifier must be assigned so that (Prefix, Path Identifier) uniquely identifies a path advertised to a neighbor (Section 2)
	MUST	2 - How to Identify a Path	positive`unit/verifyTestPeerRIB_AddPath` negative`no test`no negative test {single-polarity}: the RIB keys on (prefix, Path ID) so the paired negative would be a same-(prefix, Path ID) collapse-to-one assertion, but no such dedup/replacement test exists in the suite; TestPeerRIB_AddPath asserts only that distinct Path IDs yield distinct entries
`RFC7911-2-2`	A BGP speaker that re-advertises a route must generate its own Path Identifier (not reuse received) (Section 2)
	MUST	2 - How to Identify a Path	positive`unit/verifyTestForwardPathIDBoundaryReceivedValues` positive`unit/verifyTestForwardPathIDDiffersForTwoSourcePeers` positive`unit/verifyTestForwardPathIDIdenticalForEveryDestination` positive`unit/verifyTestForwardPathIDKeepsTheSourceOfARebuiltFrame` positive`unit/verifyTestForwardPathIDMatchesAnnounceAndWithdraw` positive`unit/verifyTestForwardPathIDReleaseReturnsValues` positive`unit/verifyTestForwardPathIDSeparatesNonAddPathSources` positive`unit/verifyTestForwardPathIDSurvivesAttributeChange` positive`unit/verifyTestForwardPathIDWithdrawCarriesTheAnnouncedValue` positive`unit/verifyTestForwardPathIDsDifferForCollidingSources` positive`unit/verifyTestForwardPathIDsFreedOnRelayedWithdraw` positive`unit/verifyTestPathIDKeyFollowsWhatTheSourceFramed` positive`unit/verifyTestWithdrawOnlyUpdateFreesEveryIdentifierItBuys` negative`unit/verifyTestForwardPathIDStableAcrossUpdates` positive`functional/verifyadj-rib-in-replay-addpath-source.ci` positive`interop/nightlycheckAddPathReadvertiseCollision`
`RFC7911-3-1`	NLRI encoding must be extended by prepending the 4-octet Path Identifier field (Section 3)
	MUST	3 - Extended NLRI Encodings	positive`unit/verifyTestINETWithAddPath` positive`unit/verifyTestWriteNLRI_WithStoredPathID` negative`unit/verifyTestWriteNLRI_AddPath` positive`functional/verifyadj-rib-in-replay-addpath-source.ci` negative`functional/verifyadj-rib-in-replay-addpath-source.ci`
`RFC7911-4-1`	Support for multiple AFI/SAFIs must be indicated in a single instance of the ADD-PATH Capability (Section 4)
	MUST	4 - ADD-PATH Capability	positive`unit/verifyTestAddPathMultipleFamilies` negative`unit/verifyTestAddPathCapability`
`RFC7911-5-1`	To send multiple paths, speaker must advertise ADD-PATH Capability with Send/Receive set to 2 or 3 (Section 5)
	MUST	5 - Operation	positive`unit/verifyTestFromNegotiatedAddPath` positive`unit/verifyTestNegotiateAddPath` negative`unit/verifyTestFromNegotiatedAddPath`
`RFC7911-5-2`	To send multiple paths, speaker must receive ADD-PATH Capability with Send/Receive set to 1 or 3 from peer (Section 5)
	MUST	5 - Operation	positive`unit/verifyTestFromNegotiatedAddPath` positive`unit/verifyTestNegotiateAddPath` negative`unit/verifyTestFromNegotiatedAddPath`
`RFC7911-5-3`	Speaker must follow RFC 4271 procedures unless ADD-PATH is negotiated for both send and receive (Section 5)
	MUST	5 - Operation	positive`unit/verifyTestForwardSplitSameContextKeepsRawSplit` positive`unit/verifyTestRFC7606Section54ReadsTypedNLRIUnderAddPath` negative`unit/verifyTestForwardPathIDLeavesNonAddPathDestinationAlone` negative`unit/verifyTestForwardSplitConvertsAddPathContext`
`RFC7911-5-4`	When ADD-PATH is negotiated, speaker must generate route updates based on (address prefix, Path Identifier) combination using extended NLRI encodings (Section 5)
	MUST	5 - Operation	positive`unit/verifyTestForwardPathIDWithdrawOfUnknownPathLeavesNothing` positive`unit/verifyTestSplitUpdateAddPathEndToEnd` positive`unit/verifyTestWriteAnnounceUpdateWithAddPath` negative`unit/verifyTestSplitUpdateEndToEnd` negative`unit/verifyTestWriteAnnounceUpdateWithAddPath`
`RFC7911-5-5`	Peer shall act accordingly in processing an UPDATE message related to a particular AFI/SAFI (Section 5)
	SHALL	5 - Operation	positive`unit/verifyTestEnforceRFC7606_IPv4BodyAddPathLargePathIDAccepted` positive`unit/verifyTestEnforceRFC7606_MPAddPathLargePathIDAccepted` negative`unit/verifyTestEnforceRFC7606_IPv4BodyAddPathLargePathIDAccepted` negative`unit/verifyTestEnforceRFC7606_MPAddPathLargePathIDAccepted`
`RFC7911-4-2`	Invalid Send/Receive value (not 1, 2, or 3) should be treated as capability not understood and ignored per RFC 5492 (Section 4)
	SHOULD	4 - ADD-PATH Capability	positive`no test`no positive test negative`no test`no negative test
`RFC7911-5-6`	Withdraw with unknown Path Identifier should be silently ignored (Section 5)
	SHOULD	5 - Operation	positive`no test`no positive test negative`no test`no negative test
`RFC7911-5-7`	Best route per RFC 4271 should be included when more than one path is advertised, unless path was received from that neighbor (Section 5)
	SHOULD	5 - Operation	positive`no test`no positive test negative`no test`no negative test
`RFC7911-5-8`	Implementation should take special care that forwarding plane of Receiving Speaker is not affected during graceful restart (Section 5)
	SHOULD	5 - Operation	positive`no test`no positive test negative`no test`no negative test

Gaps and untested MUSTs

RFC 7911 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.

`RFC7911-2-1`

Path Identifier must be assigned so that (Prefix, Path Identifier) uniquely identifies a path advertised to a neighbor (Section 2)