Supported

RFC 5301 - Dynamic Hostname Exchange Mechanism for IS-IS

Every requirement this repository extracted from RFC 5301, 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 ways100.0%7 of 7 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 reason0.0%0 of 7 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 7 binding obligations

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

No test at all0.0%0 of 7 binding obligations

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

Proven by a recorded break0.0%0 of 22 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 MUSTs7of 15 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 7 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 7 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	15
Gated MUST-level	7
Obligations that bind Ze	7
Not applicable, so out of scope	0
Declared gaps	0
Gated with no test	0
Nightly-only evidence	0
Test tags	22
Tagged units	22
Recorded audit verdicts	0
Discrimination records	0
Summary	`rfc/short/rfc5301.md`
Requirement shard	`rfc/requirements/rfc5301.md`
RFC text	`rfc/full/rfc5301.txt`

Enrolment

Enrolled: Dynamic Hostname Exchange Mechanism for IS-IS (TLV 137): seven MUST-level requirements read from the indicative prose of section 3, all met and test-bound with positive+negative tags. 3-4 (TLV type 137), 3-5 (the length octet is the total length of the value), 3-6 (a value of 1 to 255 bytes) and 3-8 (the string is not null-terminated) are proven over the real origination path in internal/plugins/isis/lsdb (encode_test.go builds the node's own LSP and reads the framed octets out of Entry.Raw), and 3-4 also carries interop evidence: test/interop/scenarios/isis-p2p-frr renders Ze's name in FRR's IS-IS database, which FRR can only do by decoding type 137. 3-7 (the value is encoded in 7-bit ASCII) and 3-9 (the content is a domain name per RFC 2181) are enforced at the config boundary by ISISHostnameValidator (internal/component/config/validators.go), which refuses any octet outside 0x20..0x7e and any break of the RFC 2181 section 11 label lengths; the value is REFUSED rather than sanitised at emit, so the name an operator configures and the name a peer reads are the same string. 3-10 (the IDNA duty of a user-interface that permits Unicode) is met under Reading A, recorded in rfc/short/rfc5301.md: the configuring interface refuses Unicode, so the sentence's antecedent is false and no ToASCII conversion is owed. The refusal is observable in both polarities rather than annotated, and no row carries {gap} or {not-applicable}. test/isis/isis-hostname-ascii.ci proves the boundary through `ze config validate`. Enrolled 2026-08-10.

What the public ledger says

Status: Supported

What the ledger says is covered

Dynamic hostname TLV 137 origination and decode (internal/plugins/isis/packet/tlv_core.go writeHostnameTLV, internal/plugins/isis/lsdb/encode.go hostnameTLV). The advertised value is refused at the config boundary unless it is printable 7-bit ASCII and its labels satisfy RFC 2181 section 11. ISISHostnameValidator (internal/component/config/validators.go) enforces that, reached through the ze:validate extension on the hostname leaf in internal/plugins/isis/yang/ze-isis-conf.yang. Nothing sanitizes or converts the value on the way to the wire. The name an operator configures is the name a peer reads. sanitizeHostname (internal/plugins/isis/show.go) drops every octet outside 0x20..0x7e from a RECEIVED value before display, which keeps a peer's malformed advertisement out of the CLI. Obligations extracted 2026-07-30 and bound per line in rfc/short/rfc5301.md. The walk is recorded in rfc/extraction/rfc5301.json.

What the ledger says remains

Enrolled 2026-08-10. All seven gated obligations of section 3 are proven in both polarities, and no row carries {gap} or {not-applicable}. The IDNA sentence of section 3 is conditional on a user-interface that permits Unicode characters. Ze's refuses it. The antecedent is false, so no ToASCII conversion is owed. That reading is recorded in rfc/short/rfc5301.md beside the requirement. The receive path stays lenient on purpose. RFC 5301 section 4 lets a receiver ignore or install the mapping. Rejecting a peer's LSP over its hostname octets would be a denial-of-service lever.

Coverage

Bucket	Count	What it counts
Positive and negative tests	7	one part of the gated population
Annotated instead of tested	0	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	7	every gated MUST falls in exactly one bucket above

Positive and negative tests (7): RFC5301-3-4, RFC5301-3-5, RFC5301-3-6, RFC5301-3-7, RFC5301-3-8, RFC5301-3-9, RFC5301-3-10

Requirements

Requirement	Level	Section	Tests
`RFC5301-3-4`	The Dynamic hostname TLV is defined here as TLV type 137 (Section 3)
	MUST	3	positive`unit/verifyTestISISHostnameTLVFraming` negative`unit/verifyTestISISHostnameEmptyOmitsTLV` positive`interop/nightlycheckISISDynamicHostname`
`RFC5301-3-5`	Length - total length of the value field (Section 3)
	MUST	3	positive`unit/verifyTestISISHostnameTLVFraming` negative`unit/verifyTestISISHostnameTLVFraming`
`RFC5301-3-6`	Value - a string of 1 to 255 bytes (Section 3)
	MUST	3	positive`unit/verifyTestISISHostnameTLVFraming` negative`unit/verifyTestISISHostnameEmptyOmitsTLV` positive`functional/verifyisis-hostname-ascii.ci` positive`interop/nightlycheckISISDynamicHostname`
`RFC5301-3-7`	The Value field is encoded in 7-bit ASCII (Section 3)
	MUST	3	positive`unit/verifyTestISISHostnameValidatorCharset` positive`unit/verifyTestLoadConfigRefusesAnISISHostnameOutside7BitASCII` negative`unit/verifyTestISISHostnameValidatorCharset` positive`functional/verifyisis-hostname-ascii.ci` positive`functional/verifyisis-hostname-startup-refused.ci`
`RFC5301-3-8`	The string is not null-terminated (Section 3)
	MUST NOT	3	positive`unit/verifyTestISISHostnameTLVFraming` negative`unit/verifyTestISISHostnameTLVIsPrintableASCII`
`RFC5301-3-9`	The content of this value is a domain name, see [RFC2181] (Section 3)
	MUST	3	positive`unit/verifyTestISISHostnameValidatorLabels` negative`unit/verifyTestISISHostnameValidatorLabels` positive`functional/verifyisis-hostname-ascii.ci`
`RFC5301-3-10`	If a user-interface for configuring or displaying this field permits Unicode characters, that user-interface is responsible for applying the ToASCII and/or ToUnicode algorithm as described in [RFC3490] to achieve the correct format for transmission or display (Section 3)
	MUST	3	positive`unit/verifyTestISISHostnameUnicodeRefusedNotConverted` negative`unit/verifyTestISISHostnameTLVIsPrintableASCII` positive`functional/verifyisis-hostname-ascii.ci`
`RFC5301-3-1`	The use of FQDN or a subset of it is strongly recommended (Section 3)
	SHOULD	3	positive`no test`no positive test negative`no test`no negative test
`RFC5301-3-3`	If this TLV is present in a pseudonode LSP, then it SHOULD NOT be interpreted as the DNS hostname of the router (Section 3)
	SHOULD NOT	3	positive`no test`no positive test negative`no test`no negative test
`RFC5301-4-1`	If a system receives a mapping for a name or system ID that is different from the mapping in the local cache, an implementation SHOULD replace the existing mapping with the latest information (Section 4)
	SHOULD	4 - Implementation	positive`no test`no positive test negative`no test`no negative test
`RFC5301-3-2`	This TLV may be present in any fragment of a non-pseudonode LSP (Section 3)
	MAY	3	positive`no test`no positive test negative`no test`no negative test
`RFC5301-3-11`	The Dynamic hostname TLV is optional (Section 3)
	OPTIONAL	3	positive`no test`no positive test negative`no test`no negative test
`RFC5301-4-2`	When originating an LSP, a router may decide to include this TLV in its LSP (Section 4)
	MAY	4 - Implementation	positive`no test`no positive test negative`no test`no negative test
`RFC5301-4-3`	Upon receipt of an LSP with the Dynamic hostname TLV, a router may decide to ignore this TLV, or to install the symbolic name and system ID in its hostname mapping table for the IS-IS network (Section 4)
	MAY	4 - Implementation	positive`no test`no positive test negative`no test`no negative test
`RFC5301-4-4`	A router may also optionally insert this TLV in its pseudonode LSP for the association of a symbolic name to a local LAN (Section 4)
	MAY	4 - Implementation	positive`no test`no positive test negative`no test`no negative test

Gaps and untested MUSTs

RFC 5301 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.