OSPF Version 2 Management Information Base
obsoleted by
- rfc-1252 — OSPF Version 2 Management Information Base
updated by
- rfc-1349 — Type of Service in the Internet Protocol Suite
Extracted elements (28)
DEFVAL clauses are provided for nearly every object to minimize parameterization; the simplest valid OSPF configuration requires only a single SNMP SET (ospfAdminStat := enabled), after which the process auto-discovers interfaces, derives metrics from ifSpeed, and places all interfaces in backbone area 0.0.0.0.
In the absence of a standard SNMP security architecture, implementations are explicitly permitted to implement read-write MIB objects as read-only and provide an alternative management interface for their modification, since the MIB is designed for protocol management not just monitoring.
Interface metrics are placed in a separate ospfIfMetricTable rather than inline in ospfIfTable in order to simplify handling of multiple Types of Service and to provide flexibility if the IP TOS definition is changed in the future.
The default TOS 0 metric formula Metric = 10^8 / ifSpeed yields values naturally proportional to bit duration; this produces well-known typical values (e.g., Ethernet=10, T1=65, 9.6 kbps=10416) without requiring explicit operator configuration.
ospfIfAuthKey and ospfVirtIfAuthKey always return a zero-length OCTET STRING when read via SNMP, regardless of the actual configured key, preventing key material from being exposed over the management channel.
ospfVirtIfRtrDeadInterval must be the same for the virtual neighbor; ospfVirtIfHelloInterval must also be the same for the virtual neighbor, mirroring the requirement for physical interfaces.
ospfIfHelloInterval must be the same for all routers attached to a common network; ospfIfRtrDeadInterval must also be the same for all routers attached to a common network.
When creating a conceptual row, management stations should include as many columnar objects as possible (especially all read-write objects) in the Set-Request; agents should accept a Set-Request with as few objects as needed, per the Internet Robustness Principle.
Default interface timer values are: HelloInterval=10 seconds, RtrDeadInterval=40 seconds, RetransInterval=5 seconds, TransitDelay=1 second, PollInterval=120 seconds (larger interval for inactive NBMA neighbors).
ospfAreaRangeTable (OID ospf 5) describes address range summaries configured to be propagated out of an area; each entry is indexed by ospfAreaRangeAreaID and ospfAreaRangeNet, with ospfAreaRangeMask (IpAddress) and ospfAreaRangeStatus (Validation).
ospfAreaTable (OID ospf 2) describes configured OSPF areas; each OspfAreaEntry is indexed by ospfAreaId and includes ospfAuthType (none=0, simplePassword=1), ospfImportASExtern (TruthValue), ospfSpfRuns (Counter), ospfAreaBdrRtrCount, ospfASBdrRtrCount, ospfAreaLSACount, and ospfAreaLSACksumSum.
ospfGeneralGroup (OID ospf 1) contains global variables for the OSPF process, including ospfRouterId (32-bit RouterID), ospfAdminStat (enabled/disabled), ospfVersionNumber (read-only, value 2), ospfAreaBdrRtrStatus, ospfASBdrRtrStatus, ospfExternLSACount, ospfExternLSACksumSum, ospfTOSSupport, ospfOriginateNewLSAs, and ospfRxNewLSAs.
ospfHostTable (OID ospf 6) lists directly attached hosts and per-TOS metrics to be advertised as host routes; each OspfHostEntry is indexed by ospfHostIpAddress and ospfHostTOS, with ospfHostMetric (Metric, 16-bit unsigned) and ospfHostStatus.
ospfIfAuthKey is a read-write OCTET STRING holding the authentication key; when the area uses simplePassword, the agent left-adjusts and zero-fills the key to 8 octets; when read, the object always returns a zero-length octet string to protect the key value.
ospfIfMetricTable (OID ospf 8) stores per-TOS metrics for non-virtual interfaces; indexed by ospfIfMetricIpAddress, ospfIfMetricAddressLessIf, and ospfIfMetricTOS; the default TOS 0 metric is computed as 10^8 / ifSpeed; metric value 0xFFFF means 'no route via this TOS'.
ospfIfTable (OID ospf 7) augments ifTable with OSPF-specific interface parameters; indexed by ospfIfIpAddress and ospfAddressLessIf (0 for addressed interfaces, ifIndex for addressless), and includes area assignment, interface type (broadcast/nbma/pointToPoint), timer values, DR/BDR addresses, event counter, and ospfIfAuthKey.
ospfLsdbChecksum is the Fletcher checksum of the complete LSA contents excluding the age field; excluding age allows the age to be incremented without recomputing the checksum.
ospfLsdbSequence is a signed 32-bit INTEGER starting at 0x80000001 (-0x7FFFFFFF) and incrementing to 0x7FFFFFFF; larger sequence numbers indicate more recent LSAs, used to detect old and duplicate advertisements.
ospfLsdbTable (OID ospf 4) represents the OSPF link-state database; each OspfLsdbEntry is indexed by ospfLsdbAreaId, ospfLsdbType (routerLink/networkLink/summaryLink/asSummaryLink/asExternalLink), ospfLsdbLSID, and ospfLsdbRouterId, and exposes ospfLsdbSequence, ospfLsdbAge, ospfLsdbChecksum, and ospfLsdbAdvertisement (full raw LSA as OCTET STRING).
ospfNbrTable (OID ospf 10) describes non-virtual OSPF neighbors; indexed by ospfNbrIpAddr and ospfNbrAddressLessIndex; includes ospfNbrRtrId, ospfNbrOptions (bit mask for external routing capability and TOS support), ospfNbrPriority, ospfNbrState, ospfNbrEvents, ospfNbrLSRetransQLen, and ospfNBMANbrStatus.
ospfRouterId is a mandatory read-write 32-bit integer (type RouterID, same encoding as IpAddress) uniquely identifying the router within the Autonomous System; by convention it should default to one of the router's IP interface addresses.
ospfStubAreaTable (OID ospf 3) describes the TOS metrics advertised by a default Area Border Router into a stub area; indexed by ospfStubAreaID and ospfStubTOS, with ospfStubMetric (BigMetric, 24-bit unsigned) and ospfStubStatus (Validation).
ospfVirtIfTable (OID ospf 9) describes OSPF virtual links; indexed by ospfVirtIfAreaID (the transit area, which must not be 0.0.0.0) and ospfVirtIfNeighbor (RouterID); virtual interface state is limited to down(1) or pointToPoint(4).
ospfVirtNbrTable (OID ospf 11) is read-only and describes virtual neighbors discovered through virtual links; indexed by ospfVirtNbrArea and ospfVirtNbrRtrId; includes ospfVirtNbrIpAddr, ospfVirtNbrOptions, ospfVirtNbrState, ospfVirtNbrEvents, and ospfVirtNbrLSRetransQLen.
Textual conventions defined in this MIB include: AreaID and RouterID (both IpAddress format), Metric (1..0xFFFF), BigMetric (1..0xFFFFFF), TruthValue (true=1/false=2), Status (enabled=1/disabled=2), Validation (valid=1/invalid=2), HelloRange (1..0xFFFF seconds), UpToMaxAge (1..3600 seconds), and DesignatedRouterPriority (0..255).
The Security Considerations section states that security issues are not discussed in this memo. The MIB does include per-area authentication type (none or simplePassword) and read-write ospfIfAuthKey/ospfVirtIfAuthKey, but authentication key exposure via SNMP GET is prevented by returning a zero-length string.
ospfIfState encodes the OSPF interface finite state machine with states: down(1), loopback(2), waiting(3), pointToPoint(4), designatedRouter(5), backupDesignatedRouter(6), otherDesignatedRouter(7); default is down.
ospfNbrState encodes the OSPF neighbor state machine with states: down(1), attempt(2), init(3), twoWay(4), exchangeStart(5), exchange(6), loading(7), full(8); the same encoding is reused for ospfVirtNbrState.