Definitions of Textual Conventions (TCs) for Bidirectional Forwarding Detection (BFD) Management
Extracted elements (18)
BfdCtrlDestPortNumberTC syntax is left open to the full range 0..65535 rather than restricting it to only the three defined BFD port values (3784, 4784, 6784) for two reasons: to allow implementations that use non-compliant port numbers for valid proprietary reasons, and to accommodate potential future extension documents.
TC names are prefixed with either 'Bfd' or 'IANA' to make it obvious to readers which conventions are BFD-module-specific and which are IANA-maintained, enabling two separate MIB modules (BFD-TC-STD-MIB and IANA-BFD-TC-STD-MIB) with distinct governance.
Every usage of IANAbfdSessAuthenticationKeyTC must specify the IANAbfdSessAuthenticationTypeTC object that provides context for interpreting the key, and it is suggested that the type object be logically registered before the key object when they appear in the same logical row.
Attempts to set an IANAbfdSessAuthenticationKeyTC object to a value inconsistent with the associated IANAbfdSessAuthenticationTypeTC must fail with an inconsistentValue error. The key value must always be consistent with the associated authentication type.
When IANAbfdSessAuthenticationKeyTC is used as an index object, the object definition MUST include a SIZE clause to limit the number of potential instance sub-identifiers due to the 128 sub-identifier limit in SMIv2.
BfdCtrlDestPortNumberTC is a Textual Convention for the UDP destination port of BFD control packets. Port 3784 represents single-hop, 4784 multi-hop, and 6784 BFD on LAG sessions; the value 0 is reserved for special conditions.
BfdCtrlSourcePortNumberTC is a Textual Convention for the UDP source port of BFD control packets, referencing the ephemeral range 49152..65535 from RFC 5881. The value 0 is reserved for special conditions and is not a valid port number.
BfdIntervalTC is a Textual Convention representing the BFD interval in microseconds. It is an Unsigned32 with range 0..4294967295.
BfdMultiplierTC is a Textual Convention for the BFD failure detection multiplier. It is an Unsigned32 restricted to values 1..255.
BfdSessIndexTC is a Textual Convention for uniquely identifying BFD sessions. It is an Unsigned32 with range 1..4294967295, displayed as a decimal integer.
IANAbfdDiagTC is a Textual Convention enumerating common BFD diagnostic codes (0–9): noDiagnostic, controlDetectionTimeExpired, echoFunctionFailed, neighborSignaledSessionDown, forwardingPlaneReset, pathDown, concatenatedPathDown, administrativelyDown, reverseConcatenatedPathDown, and misConnectivityDefect.
IANAbfdSessAuthenticationTypeTC is a Textual Convention enumerating BFD authentication types: noAuthentication(-1), reserved(0), simplePassword(1), keyedMD5(2), meticulousKeyedMD5(3), keyedSHA1(4), and meticulousKeyedSHA1(5), per RFC 5880 Sections 4.2–4.4.
IANAbfdSessOperModeTC is a Textual Convention enumerating BFD operating modes: asyncModeWEchoFunction(1), asynchModeWOEchoFunction(2), demandModeWEchoFunction(3), and demandModeWOEchoFunction(4), as defined in RFC 5880.
IANAbfdSessTypeTC is a Textual Convention enumerating BFD session types: singleHop(1), multiHopTotallyArbitraryPaths(2), multiHopOutOfBandSignaling(3), and multiHopUnidirectionalLinks(4), as defined in RFC 5880, 5881, and 5883.
IANA assigned OID { mib-2 223 } to the BFD-TC-STD-MIB module and OID { mib-2 224 } to the IANA-BFD-TC-STD-MIB module. The IANA-BFD-TC-STD-MIB is under direct IANA control with updates via IETF Review (RFC 5226).
RFC 7330 defines only Textual Conventions and does not define any management objects itself. Because meaningful security considerations can only be written in MIB modules that define management objects, this document has no direct impact on Internet security; security considerations are deferred to BFD MIB modules that import these TCs.
IANAbfdSessStateTC enumerates BFD session states: adminDown(1), down(2), init(3), up(4), and failing(5). The failing(5) state is only applicable when the session runs BFD version 0.
IANAbfdSessAuthenticationKeyTC is an OCTET STRING of SIZE(0..252) representing the BFD authentication key. Key length constraints vary by authentication type: SIZE(0) for noAuthentication/reserved, SIZE(1..16) for simplePassword, SIZE(16) for keyedMD5/meticulousKeyedMD5, and SIZE(20) for keyedSHA1/meticulousKeyedSHA1.