Fibre Channel Management MIB
obsoletes
- rfc-2837 — Definitions of Managed Objects for the Fabric Element in Fibre Channel Standard
Extracted elements (29)
The fcmPortLcStatsGroup provides Counter32-based ('low-capacity') equivalents for the Counter64 statistics in fcmPortClass23StatsGroup. This was added because some older SNMP systems do not yet support Counter64 objects, allowing those systems to still implement useful statistics.
The MIB introduces the concept of a 'Fibre Channel management instance' (indexed by fcmInstanceIndex) to allow a single SNMP agent with multiple AgentX sub-agents to represent multiple FC management instances within the same SNMP context. All tables are indexed by this arbitrary integer.
This MIB obsoletes both RFC 2837 and the Fibre Channel Management Integration MIB (MIB-FA). Section 12 documents problems with the FCMIM MIB (e.g., use of proprietary constructs, lack of conformance statements) and section 13 details the changes from RFC 2837, explaining why a clean replacement rather than an amendment was chosen.
Each Fibre Channel port MUST have its own row in the IF-MIB's ifTable. The value of ifType for a Fibre Channel interface is 56. ifRcvAddressTable does not apply to FC interfaces, and no sublayers are defined, so FC interfaces are not stacked in ifStackTable.
Fibre Channel management instances with a corresponding physical component use fcmInstancePhysicalIndex to point to the entPhysicalIndex in the Entity MIB (RFC 2737). A value of zero indicates no correspondence; implementations are not required to support non-zero values.
Fibre Channel management instances with a corresponding software module use fcmInstanceSoftwareIndex to point to hrSWInstalledIndex in the Host Resources MIB (RFC 2790). A value of zero indicates no correspondence; agents are not required to support non-zero values.
For Fibre Channel interfaces, ifInOctets, ifOutOctets and their high-capacity variants count octets contained in frames between the Start-of-Frame and End-of-Frame delimiters, excluding the delimiters themselves.
ifInErrors for a Fibre Channel interface is defined as the sum of fcmPortLossofSynchs, fcmPortLossofSignals, fcmPortPrimSeqProtocolErrors, fcmPortInvalidTxWords, fcmPortInvalidCRCs, fcmPortAddressErrors, fcmPortDelimiterErrors, fcmPortTruncatedFrames, fcmPortEncodingDisparityErrors, plus input-error entries in fcmPortOtherErrors.
The value of fcmInstanceIndex MUST be kept constant between restarts of the SNMP agent, and every possible effort MUST be made to keep it constant across restarts. It is unrealistic to expect it to remain constant across all re-configurations (e.g., replacement of all non-volatile storage).
The value of fcmSwitchIndex MUST be kept constant between restarts of the agent and every possible effort MUST be made to keep it constant across restarts, analogous to fcmInstanceIndex.
When auto-negotiation is implemented and enabled on a Fibre Channel interface but no operational speed has yet been negotiated, ifSpeed and ifHighSpeed SHOULD reflect the maximum speed supported by the interface.
FcAddressIdOrZero is a textual convention for a 24-bit Fibre Channel Address Identifier, unique within a Fabric's address space. Encoded as OCTET STRING of size 0 (unassigned) or 3 bytes.
FcClasses is a BITS textual convention representing Fibre Channel classes of service: classF(0), class1(1), class2(2), class3(3), class4(4), class5(5), class6(6). Used to express both capability and operational classes on a port.
FcDataFieldSize constrains the receive data field size of an FC port to the range 128..2112 bytes. FcBbCredit constrains buffer-to-buffer credit to 0..32767 buffers. Both are used extensively in port and login tables.
fcmFLoginTable (indexed by {ifIndex, fcmFLoginNxPortIndex}) records service parameters negotiated during Fabric Login for each Nx_Port attached to an Fx_Port: port and node WWNs, BB credit model (regular or alternate), BB credit, agreed classes of service, and Class 2/3 sequential delivery agreement and data field sizes.
fcmFxPortTable (indexed by ifIndex) holds Fx_Port-specific parameters: RATOV (Resource_Allocation_Timeout in ms), EDTOV (Error_Detect_Timeout in ms), RTTOV (Receiver_Transmitter_Timeout in ms), hold time (microseconds), and capability ranges for BB credit, data field size, hold time, and Class 2/3 sequential delivery support.
fcmInstanceTable (fcmgmtObjects 1) holds per-management-instance attributes: WWN, functions performed, pointer to Entity MIB physical component (fcmInstancePhysicalIndex), pointer to Host Resources MIB software module (fcmInstanceSoftwareIndex), operational status, text name, description, and fabric identifier.
fcmISPortTable (indexed by ifIndex) holds attributes specific to E_Ports and B_Ports: fcmISPortClassFCredit (read-write, BB credit for Class F frames) and fcmISPortClassFDataFieldSize (agreed Receive Data Field Size for Class F FT_1 frames).
fcmLinkTable (indexed by {fcmInstanceIndex, fcmLinkIndex}) records FC link topology as known to local management instances. Each entry captures both ends of a link (node WWN, physical port number, port WWN), plus the remote end's agent address, port type, unit type, and FC address identifier.
fcmPortErrorsTable (AUGMENTS fcmPortEntry) defines 18 Counter32 error counters per port, including link failures, loss of sync/signal, primitive sequence protocol errors, invalid Tx words, invalid CRCs, invalid ordered sets, frame-too-long, truncated frames, address errors, delimiter errors, encoding disparity errors, and a catch-all fcmPortOtherErrors.
fcmPortStatsTable (AUGMENTS fcmPortEntry) provides per-port traffic statistics using Counter64 for Class 2 (Rx/Tx frames and octets, discards, F_BSY/P_BSY/F_RJT/P_RJT counts) and Class 3 (Rx/Tx frames and octets, discards), and Counter32 for Class F traffic on E_Ports.
fcmPortTable (fcmgmtObjects 3) is indexed by ifIndex and holds per-port attributes including port and node WWNs, admin/oper port type, FC classes capability and operational, transmitter type, connector type, serial number, physical port number, admin speed, and capable/operational higher-level protocols.
fcmSwitchTable (fcmgmtObjects 2) is indexed by {fcmInstanceIndex, fcmSwitchIndex} and records per-switch attributes: domain ID (FcDomainIdOrZero, 0..239), whether the switch is principal (TruthValue), and the switch WWN.
FcNameIdOrZero is a textual convention for World Wide Names (WWNs): an OCTET STRING of size 0 (unassigned/unknown), 8 (64-bit WWN), or 16 (128-bit WWN for future use). Used throughout the MIB to identify FC entities.
FcPortType is a textual convention typed as Unsigned32, with values assigned by IANA from the FC Port Type Registry. Agents use fcmPortAdminType (read-write) and fcmPortOperType (read-only) to express desired and current port types.
FcUnitFunctions is a BITS textual convention enumerating FC interconnect element functions: other(0), hub(1), switch(2), bridge(3), gateway(4), host(5), storageSubsys(6), storageAccessDev(7), nas(8), wdmux(9), storageDevice(10). Used in fcmInstanceFunctions.
IANA maintains an FC Port Type Registry (referenced by the FcPortType textual convention). Section 11.2 requests IANA to create this registry; the OID for fcMgmtMIB is assigned at transmission 56 (::= { transmission 56 }).
Several MIB objects have read-write access and could affect FC network behavior if accessed by unauthorized parties: fcmInstanceTextName, fcmInstanceDescr, fcmPortAdminType, fcmPortAdminSpeed, fcmSwitchDomainId, and fcmISPortClassFCredit. Implementations should apply SNMP access controls to restrict write access to authorized managers.
The MIB is compliant with SNMPv2-CONF and is intended to be used with SNMP. RFC 3410 security recommendations apply; implementations should support SNMPv3 with authentication and privacy to protect the management information from unauthorized access or modification.