The Definitions of Managed Objects for IP Mobility Support using SMIv2
Extracted elements (27)
MIB management functionality is partitioned among Mobile Node, Foreign Agent, and Home Agent to mirror the architectural partition in the Mobile IP protocol itself, ensuring each managed entity only needs to implement the groups relevant to its role.
Object selection was deliberately constrained to items essential for fault or configuration management, excludes objects derivable from other MIBs, and limits the total count — reflecting IAB directives for focused, minimal MIB design.
The mnAdvSequence object ranges from 0 to 0xffff (65535), but after reaching 0xffff it rolls over to 256 rather than 0, matching the Mobile IP protocol behavior that distinguishes a rollover from an agent reboot (sequence numbers 0–255 signal reboot).
The maAdvAddress object MUST be set to either the all-systems multicast address (224.0.0.1) or the limited-broadcast address (255.255.255.255); no other values are permissible for agent advertisement destination.
The maAdvertisementGroup is mandatory for both Home Agents and Foreign Agents because all mobility agents must implement Agent Advertisement.
The mipSecAssociationGroup is mandatory for Mobile Nodes and Home Agents; Foreign Agents must implement it only if they maintain any security associations.
The mipSystemGroup (mipEntities, mipEnable, mipEncapsulationSupported) is the sole MANDATORY-GROUP in the compliance statement; all other groups are conditionally mandatory depending on entity type (MN, FA, or HA).
Foreign agent denial counters enumerate refusal reasons by code: reasonUnspecified (64), admProhibited (65), insufficientResource (66), mnAuthenticationFailure (67), haAuthenticationFailure (68), regLifetimeTooLong (69), poorlyFormedRequest (70), encapsulationUnavailable (72), vjCompressionUnavailable (73), and haUnreachable (80–95).
Home agent denial counters correspond to reply codes 128–136: reasonUnspecified, admProhibited, insufficientResource, mnAuthenticationFailure, faAuthenticationFailure, idMismatch, poorlyFormedRequest, tooManyBindings, unknownHA; Code 1 (haMultiBindingUnsupported) counts accepted-but-simultaneous-bindings-unsupported replies.
The faVisitorTable is the foreign agent's visitor list, indexed by the source IP address of the visitor's Registration Request, and contains home address, home agent address, granted lifetime, countdown timer, registration flags, 64-bit identification, and acceptance status per visiting mobile node.
The haCounterTable tracks per-mobile-node registration statistics at the home agent, including service requests accepted/denied, overall service time (Gauge32 in seconds since last HA reboot), timestamps of most recent accept and deny, and the most recent denial code (reasonUnspecified through unknownHA, codes 128–136).
The haMobilityBindingTable stores the home agent's mobility binding list indexed by mobile node home address and care-of address, recording the registration source address (either co-located COA or FA address), flags, 64-bit identification, granted lifetime, and remaining time.
The maAdvConfigTable provides per-interface advertisement configuration for mobility agents, including maAdvMaxRegLifetime, maAdvAddress (must be 224.0.0.1 or 255.255.255.255), maAdvMaxInterval (4..1800s), maAdvMinInterval (3..1800s), maAdvMaxAdvLifetime (4..9000s), and maAdvResponseSolicitationOnly (default false).
The MIB is partitioned into twelve groups: mipSystemGroup, mipSecAssociationGroup, mipSecViolationGroup, mnSystemGroup, mnDiscoveryGroup, mnRegistrationGroup, maAdvertisementGroup, faSystemGroup, faAdvertisementGroup, faRegistrationGroup, haRegistrationGroup, and haRegNodeCountersGroup, each assigned to specific Mobile IP entities (MN, FA, HA).
The mipAuthFailure NOTIFICATION-TYPE conveys mipSecViolatorAddress, mipSecRecentViolationSPI, mipSecRecentViolationIDLow, mipSecRecentViolationIDHigh, and mipSecRecentViolationReason when authentication of a Registration Request or Reply fails; implementation is optional.
The mipEncapsulationSupported object is a BITS type advertising which encapsulation methods the Mobile IP entity supports: ipInIp(0), gre(1), minEnc(2), other(3); a mobile entity may support multiple methods or none.
The mipSecAssocTable stores Mobility Security Associations indexed by mipSecPeerAddress (IpAddress) and mipSecSPI (Unsigned32, 0..4294967295), with per-entry attributes for algorithm type (md5 or other), algorithm mode (prefixSuffix or other), shared key (16-octet OCTET STRING), and replay method (timestamps, nonces, or other).
The mipSecReplayMethod per-SPI object specifies the replay-protection method in use for each Mobility Security Association entry: timestamps(2) or nonces(3), in addition to other(1).
The mipSecViolationTable records per-peer security violations, capturing the violator IP address, violation count, SPI of the most recent violation, violation timestamp, 64-bit identification field (split into IDLow/IDHigh), and reason code (noMobilitySecurityAssociation, badAuthenticator, badIdentifier, badSPI, missingSecurityExtension, other).
The mnFATable is indexed by foreign agent IP address and care-of address (COA), and is updated as advertisements are received; entries expire when the advertisement lifetime expires, and one FA may appear multiple times with different COAs.
The mnHATable lists potential home agents for the mobile node, with each entry containing the HA IP address (mnHAAddress), a flag indicating whether it is the current HA (mnCurrentHA), and a RowStatus (mnHAStatus) — setting status to 'destroy' causes the MN to deregister from that HA.
The mnRegistrationTable tracks each registration attempt indexed by agent address and COA, storing registration flags, 64-bit identification, requested/granted lifetime, countdown timer (Gauge32), send timestamp, acceptance status (TruthValue), and whether the COA is locally acquired (mnCOAIsLocal).
RFC 2006 registers the Mobile IP MIB module as mib-2 44 (OID { mib-2 44 }), defining managed objects for the Mobile Node, Foreign Agent, and Home Agent under SMIv2.
The mipSecKey object (16-octet shared secret) is read-create but always returns a zero-length value when read, preventing shared secrets from being exposed via SNMP GET operations.
The Mobile IP MIB affords network operators the ability to configure and control Mobile IP links; read-write and read-create objects (such as mipEnable, security association parameters, and advertisement configuration) should be protected using SNMPv2 security mechanisms to prevent unauthorized modification.
The mnState object defines five Mobile Node states: home (connected to home network), registered (registered on foreign network), pending (awaiting registration reply), isolated (no network connectivity), and unknown (state cannot be determined).
The RegistrationFlags textual convention is encoded as a BITS type with six named bits: vjCompression(0), gre(1), minEnc(2), decapsulationByMN(3), broadcastDatagram(4), and simultaneousBindings(5), corresponding to the second byte of the Mobile IP Registration Request message.