No row in the public ledger

RFC 905 - ISO Transport Protocol Specification (ISO DP 8073)

Every requirement this repository extracted from RFC 905, 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%6 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 reason0.0%0 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 19 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 10 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 scope3of 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 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	No row in the public ledger
Enrolment	Enrolled
Requirements	10
Gated MUST-level	9
Obligations that bind Ze	6
Not applicable, so out of scope	3
Declared gaps	0
Gated with no test	0
Nightly-only evidence	0
Test tags	19
Tagged units	19
Recorded audit verdicts	0
Discrimination records	0
Summary	`rfc/short/rfc905.md`
Requirement shard	`rfc/requirements/rfc905.md`
RFC text	`rfc/full/rfc905.txt`

Enrolment

Enrolled: ISO Transport Protocol: nine MUST-level requirements. The six that ze realizes are the Annex B Fletcher checksum (mod-255 arithmetic, two-pass generation, verify-both-sums-zero, OSPF LSA checksum excluding LS Age, encode+decode vectors) -- x-1,x-2,x-3,x-4,x-6,x-7 -- each bound with positive+negative tags on the IS-IS (internal/plugins/isis/packet/checksum.go) and OSPF (internal/plugins/ospf/types/checksum.go, ospf/packet/checksum.go) checksum tests. The three ISO Transport TPDU MUSTs (6.17.3-1 generation, 6.17.3-2 receive/verify-and-discard, 13.2.3.1-1 0xC3 checksum parameter) are {not-applicable}: ze has no ISO Transport TPDU sender/receiver and no 0xC3 transport-checksum-parameter code path.

What the public ledger says

No row in the public ledger, so its summary declares `| Support | - |` and docs/features/rfc-status.md carries no row for RFC 905.

Coverage

Bucket	Count	What it counts
Positive and negative tests	6	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	9	every gated MUST falls in exactly one bucket above

Positive and negative tests (6): RFC905-x-1, RFC905-x-2, RFC905-x-3, RFC905-x-4, RFC905-x-6, RFC905-x-7

Annotated instead of tested (3): RFC905-6.17.3-1, RFC905-6.17.3-2, RFC905-13.2.3.1-1

Requirements

Requirement	Level	Section	Tests
`RFC905-6.17.3-1`	Sender sets the checksum so SUM(a[i]) == 0 and SUM(i*a[i]) == 0, both mod 255, over octets 1..L (Section 6.17.3)
	MUST	6.17.3	positive`no test`no positive test negative`no test`no negative test {not-applicable}: ze implements the RFC 905 Annex B Fletcher checksum (reused by IS-IS at internal/plugins/isis/packet/checksum.go and OSPF at internal/plugins/ospf/types/checksum.go) but has no ISO Transport Protocol TPDU generator that sets a transport checksum parameter (grep for TPDU/TP4/0xC3 across internal/ is empty)
`RFC905-6.17.3-2`	Receiver (when checksum agreed) discards a TPDU that does not satisfy both checksum formulas (Section 6.17.3)
	MUST	6.17.3	positive`no test`no positive test negative`no test`no negative test {not-applicable}: ze implements the RFC 905 Annex B Fletcher checksum (reused by IS-IS at internal/plugins/isis/packet/checksum.go and OSPF at internal/plugins/ospf/types/checksum.go) but has no ISO Transport Protocol TPDU receiver that verifies and discards a transport TPDU (grep for TPDU/TP4/0xC3 across internal/ is empty)
`RFC905-x-1`	Use modulo-255 (one's-complement) arithmetic, NOT modulo 256, for both running sums (Annex B.2)
	MUST	x	positive`unit/verifyTestISISChecksumFixedVector` positive`unit/verifyTestISISChecksumModulus` negative`unit/verifyTestISISChecksumDetectsCorruption`
`RFC905-x-2`	Generation pass 1: zero the checksum field, then run C0 += octet, C1 += C0 over i = 1..L (Annex B.3.1-B.3.3)
	MUST	x	positive`unit/verifyTestISISChecksumVectors` negative`unit/verifyTestISISChecksumDetectsCorruption`
`RFC905-x-3`	Generation pass 2: X = -C1 + (L-n)C0 ; Y = C1 - (L-n+1)C0 (mod 255), placed at octets n and n+1 (Annex B.3.4-B.3.5)
	MUST	x	positive`unit/verifyTestISISChecksumFixedVector` positive`unit/verifyTestISISChecksumVectors` negative`unit/verifyTestISISChecksumDetectsCorruption`
`RFC905-x-4`	Verification: run C0 += octet, C1 += C0 over the whole TPDU INCLUDING the checksum octets; both C0 and C1 MUST be zero (Annex B.4)
	MUST	x	positive`unit/verifyTestISISChecksumVectors` negative`unit/verifyTestISISChecksumDetectsCorruption` negative`unit/verifyTestOSPFLSAChecksumExcludesAge`
`RFC905-x-5`	Treat a computed octet of 0 as 255 so the field cannot collide with the reserved all-zero "no checksum" value (Annex B.2)
	SHOULD	x	positive`no test`no positive test negative`no test`no negative test
`RFC905-13.2.3.1-1`	Encode the checksum parameter as code 0xC3, length 2, value = the two octets X, Y (Section 13.2.3.1)
	MUST	13.2.3.1	positive`no test`no positive test negative`no test`no negative test {not-applicable}: ze implements the RFC 905 Annex B Fletcher checksum (reused by IS-IS at internal/plugins/isis/packet/checksum.go and OSPF at internal/plugins/ospf/types/checksum.go) but has no ISO Transport Protocol code path that encodes the 0xC3 transport checksum parameter (grep for TPDU/TP4/0xC3 across internal/ is empty)
`RFC905-x-6`	(OSPF reuse) Compute the LSA Fletcher-16 over the LSA starting at the Options field, EXCLUDING the 2-byte LS Age, with the LS Checksum field zeroed during the forward computation (RFC 2328 Section 12.1.7)
	MUST	x	positive`unit/verifyTestFletcherIgnoresLSAge` positive`unit/verifyTestFletcherRFC905Vectors` positive`unit/verifyTestOSPFLSAChecksum` negative`unit/verifyTestOSPFLSAChecksumExcludesAge`
`RFC905-x-7`	(OSPF reuse) Test BOTH encode (X,Y placement) and decode (verify-to-zero) against vectors; a common bug is encode-correct / verify-wrong, which passes self-interop but fails cross-interop
	MUST	x	positive`unit/verifyTestFletcherRFC905Vectors` positive`unit/verifyTestISISChecksumVectors` positive`unit/verifyTestOSPFLSAChecksum` negative`unit/verifyTestOSPFLSAChecksumExcludesAge`

Gaps and untested MUSTs

Requirement	State	Reason
`RFC905-6.17.3-1` Sender sets the checksum so SUM(a[i]) == 0 and SUM(i*a[i]) == 0, both mod 255, over octets 1..L (Section 6.17.3)	no test	no test carries this requirement id; annotated {not-applicable}: ze implements the RFC 905 Annex B Fletcher checksum (reused by IS-IS at internal/plugins/isis/packet/checksum.go and OSPF at internal/plugins/ospf/types/checksum.go) but has no ISO Transport Protocol TPDU generator that sets a transport checksum parameter (grep for TPDU/TP4/0xC3 across internal/ is empty)
`RFC905-6.17.3-2` Receiver (when checksum agreed) discards a TPDU that does not satisfy both checksum formulas (Section 6.17.3)	no test	no test carries this requirement id; annotated {not-applicable}: ze implements the RFC 905 Annex B Fletcher checksum (reused by IS-IS at internal/plugins/isis/packet/checksum.go and OSPF at internal/plugins/ospf/types/checksum.go) but has no ISO Transport Protocol TPDU receiver that verifies and discards a transport TPDU (grep for TPDU/TP4/0xC3 across internal/ is empty)
`RFC905-13.2.3.1-1` Encode the checksum parameter as code 0xC3, length 2, value = the two octets X, Y (Section 13.2.3.1)	no test	no test carries this requirement id; annotated {not-applicable}: ze implements the RFC 905 Annex B Fletcher checksum (reused by IS-IS at internal/plugins/isis/packet/checksum.go and OSPF at internal/plugins/ospf/types/checksum.go) but has no ISO Transport Protocol code path that encodes the 0xC3 transport checksum parameter (grep for TPDU/TP4/0xC3 across internal/ is empty)

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.

`RFC905-6.17.3-1`

Sender sets the checksum so SUM(a[i]) == 0 and SUM(i*a[i]) == 0, both mod 255, over octets 1..L (Section 6.17.3)