OSPF Version 2 Management Information Base
obsoleted by
- rfc-1850 — OSPF Version 2 Management Information Base
obsoletes
- rfc-1252 — OSPF Version 2 Management Information Base
Extracted elements (26)
In the absence of a standard SNMP security architecture, read-write MIB objects may be implemented as read-only with an alternative (non-SNMP) interface for modification, acknowledging the security gap in the SNMP v1 framework.
Interface metrics are placed in a separate ospfIfMetricTable (rather than in ospfIfTable) to simplify handling of multiple TOS values and to provide flexibility if the IP TOS definition changes in the future.
Row deletion in conceptual tables is accomplished by setting a Validation object to 'invalid' rather than issuing a delete operation; the actual internal effect (row removal) is implementation-dependent, following SMIv1 conceptual row conventions.
The default TOS-0 metric is defined as 10^8/ifSpeed, yielding values such as 1 for >=100 Mbps, 10 for Ethernet, 65 for T1, and 10416 for 9.6 kbps; this makes metrics a measure of bit duration and produces unambiguous, technology-neutral values without manual configuration.
The MIB is designed so that enabling OSPF requires only a single SET (ospfAdminStat := enabled); all other parameters have DEFVAL clauses providing sensible defaults, minimizing configuration complexity for typical deployments.
For row creation in conceptual tables, management stations should include all read-write objects in the SET-Request; agents should accept SET-Requests with only the minimum required objects, following the Robustness Principle ('be liberal in what you accept, conservative in what you send').
The OSPF LSA sequence number (ospfLsdbSequence) is a signed 32-bit integer starting at 0x80000001 (-0x7FFFFFFF) and incrementing to 0x7FFFFFFF; implementations reading this via SNMP will observe very negative values for typical, recently originated LSAs.
ospfIfHelloInterval must be the same for all routers attached to a common network; mismatched hello intervals prevent neighbor adjacency formation.
ospfIfRtrDeadInterval must be the same for all routers attached to a common network; similarly, ospfVirtIfHelloInterval and ospfVirtIfRtrDeadInterval must match between virtual link endpoints.
ospfAreaRangeTable (ospf 5) represents address range summaries configured per area to reduce inter-area topology detail, indexed by ospfAreaRangeAreaID and ospfAreaRangeNet, with ospfAreaRangeMask defining the summarized prefix.
ospfAreaTable (ospf 2) describes configured OSPF areas, indexed by ospfAreaId (AreaID = IpAddress format). Each entry includes ospfAuthType (none=0, simplePassword=1), ospfImportASExtern, ospfSpfRuns (Dijkstra run counter), ospfAreaBdrRtrCount, ospfASBdrRtrCount, ospfAreaLSACount, and ospfAreaLSACksumSum.
ospfExternLSACksumSum is a 32-bit unsigned sum of LS checksums for all external (type 5) LSAs in the database; it can detect database changes and compare the link-state databases of two routers without enumerating all LSAs.
ospfGeneralGroup (ospf 1) contains global OSPF process variables: ospfRouterId (32-bit router identifier), ospfAdminStat (enabled/disabled), ospfVersionNumber (2), ospfAreaBdrRtrStatus, ospfASBdrRtrStatus, ospfExternLSACount, ospfExternLSACksumSum, ospfTOSSupport, ospfOriginateNewLSAs, and ospfRxNewLSAs.
ospfHostTable (ospf 6) lists directly attached hosts that the router will advertise as host routes, indexed by ospfHostIpAddress and ospfHostTOS, with ospfHostMetric (Metric = 1..0xFFFF) controlling the advertised metric per TOS.
ospfIfAuthKey is an OCTET STRING holding the authentication key for simplePassword authentication; if the key is shorter than 8 octets, the agent left-adjusts and zero-fills to 8 octets. When read, ospfIfAuthKey always returns an OCTET STRING of length zero to prevent key disclosure.
ospfIfMetricTable (ospf 8) is a separate adjunct table to ospfIfTable providing per-TOS metrics indexed by interface and TOSType. The default TOS-0 metric is computed as 10^8/ifSpeed. A value of 0xFFFF (65535) means 'no route via this TOS'.
ospfIfTable (ospf 7) describes OSPF interfaces indexed by ospfIfIpAddress and ospfAddressLessIf (0 for addressed interfaces, ifIndex for addressless). Key fields include ospfIfType (broadcast=1, nbma=2, pointToPoint=3), ospfIfRtrPriority (0..255, 0 means ineligible for DR), ospfIfTransitDelay (default 1s), ospfIfRetransInterval (default 5s), ospfIfHelloInterval (default 10s), ospfIfRtrDeadInterval (default 40s), ospfIfPollInterval (default 120s), and ospfIfAuthKey.
ospfLsdbTable (ospf 4) is the link-state database, indexed by ospfLsdbAreaId, ospfLsdbType (routerLink=1, networkLink=2, summaryLink=3, asSummaryLink=4, asExternalLink=5), ospfLsdbLSID, and ospfLsdbRouterId. It also exposes ospfLsdbSequence, ospfLsdbAge, ospfLsdbChecksum, and ospfLsdbAdvertisement (full LSA as OCTET STRING). Intended primarily for network debugging.
ospfNbrTable (ospf 10) is indexed by ospfNbrIpAddr and ospfNbrAddressLessIndex, and includes ospfNbrOptions (bit mask: bit 0 = accepts external LSAs, bit 1 = supports non-zero TOS metrics), ospfNbrPriority, ospfNbrState, ospfNbrEvents (state change counter), ospfNbrLSRetransQLen (retransmission queue depth), and ospfNBMANbrStatus (Validation) for NBMA neighbor management.
ospfStubAreaTable (ospf 3) describes the metrics advertised by a default Area Border Router into stub areas, indexed by ospfStubAreaID and ospfStubTOS (TOSType 0..31). ospfStubMetric uses BigMetric (1..0xFFFFFF). Rows are deleted by setting ospfStubStatus to 'invalid'.
ospfVirtIfTable (ospf 9) describes virtual links, indexed by ospfVirtIfAreaID (the transit area, never 0.0.0.0) and ospfVirtIfNeighbor (RouterID). Includes the same timer parameters as ospfIfTable plus ospfVirtIfAuthKey. ospfVirtIfState is limited to down(1) and pointToPoint(4).
ospfVirtNbrTable (ospf 11) is fully read-only since virtual links are configured via ospfVirtIfTable; it exposes ospfVirtNbrIpAddr, ospfVirtNbrOptions, ospfVirtNbrState, ospfVirtNbrEvents, and ospfVirtNbrLSRetransQLen for monitoring virtual neighbor relationships.
The OSPF MIB is assigned OID { mib-2 14 }, placing all OSPF managed objects under the ospf subtree within the standard MIB-II hierarchy.
The Security Considerations section explicitly states that security issues are not discussed in this memo, reflecting the known limitation that SNMP v1 lacks a security architecture for controlling write access to the numerous read-write MIB objects defined here.
ospfIfState encodes the OSPF interface state machine with states: down(1), loopback(2), waiting(3), pointToPoint(4), designatedRouter(5), backupDesignatedRouter(6), otherDesignatedRouter(7). Transitions are driven by interface events such as link up/down and DR election outcomes.
ospfNbrState and ospfVirtNbrState encode the OSPF neighbor state machine with eight states: down(1), attempt(2), init(3), twoWay(4), exchangeStart(5), exchange(6), loading(7), full(8), corresponding to OSPF Version 2 Section 10.1 neighbor state progression.