Management Information Base for Version 2 of the Simple Network Management Protocol (SNMPv2)
obsoleted by
- rfc-3418 — Management Information Base (MIB) for the Simple Network Management Protocol (SNMP)
obsoletes
- rfc-1450 — Management Information Base for version 2 of the Simple Network Management Protocol (SNMPv2)
Extracted elements (28)
snmpSetSerialNo is described as coarse-grain coordination; for fine-grain coordination, the document notes that one or more similar TestAndIncr objects might be defined within each MIB group as appropriate, leaving per-group locking to individual MIB designers.
sysServices encodes supported protocol layers as a sum of powers of two (2^(L-1) per layer) rather than a list, allowing a single INTEGER to compactly represent any combination of the seven OSI layers a node participates in.
The per-PDU-type input/output counters from RFC 1213 (e.g., snmpInGetRequests, snmpOutGetResponses) were made obsolete because SNMPv2 provides richer error information and the counters proved of limited diagnostic value while adding implementation burden.
A large set of SNMPv1 SNMP group objects defined in RFC 1213—including snmpOutPkts, snmpInTooBigs, snmpInNoSuchNames, snmpInBadValues, and many others—are declared STATUS obsolete in this MIB and collected in snmpObsoleteGroup (snmpMIBGroups 10). Implementations SHOULD NOT implement these objects.
All implementations of SNMPv2 must be capable of generating the authenticationFailure trap, though actual generation is gated by the snmpEnableAuthenTraps object.
It is strongly recommended that snmpEnableAuthenTraps be stored in non-volatile memory so that it remains constant across re-initializations of the network management system.
The snmpBasicCompliance MODULE-COMPLIANCE requires that conforming SNMPv2 entities implement the mandatory groups snmpGroup, snmpSetGroup, systemGroup, and snmpBasicNotificationsGroup. The snmpCommunityGroup is additionally mandatory for entities supporting community-based authentication.
authenticationFailure (snmpTraps 5) is a NOTIFICATION-TYPE signifying that the agent received a protocol message that is not properly authenticated. All SNMPv2 implementations must be capable of generating this trap, subject to snmpEnableAuthenTraps.
coldStart (snmpTraps 1) is a NOTIFICATION-TYPE signifying that the SNMPv2 agent is reinitializing itself and that its configuration may have been altered.
snmpBasicNotificationsGroup (snmpMIBGroups 7) defines the two notifications every SNMPv2 entity is required to implement: coldStart and authenticationFailure.
snmpEnableAuthenTraps (snmp 30) is a read-write INTEGER {enabled(1), disabled(2)} that controls whether the SNMPv2 entity is permitted to generate authenticationFailure traps; its value overrides any other configuration.
snmpGroup (snmpMIBGroups 8) collects the core instrumentation objects: snmpInPkts, snmpInBadVersions, snmpInASNParseErrs, snmpSilentDrops, snmpProxyDrops, and snmpEnableAuthenTraps.
snmpInBadCommunityNames (snmp 4) counts messages received using a community name not known to the entity; snmpInBadCommunityUses (snmp 5) counts messages representing an operation not allowed for the named community. Both are read-only Counter32 objects in the snmpCommunityGroup.
snmpProxyDrops (snmp 32) counts PDUs silently dropped because transmission of the (possibly translated) message to a proxy target failed in a manner other than a time-out such that no Response-PDU could be returned.
snmpSetSerialNo (snmpSet 1) is a read-write TestAndIncr object providing an advisory lock to allow several cooperating SNMPv2 managers to coordinate their use of the SNMPv2 set operation, intended for coarse-grain coordination.
snmpSilentDrops (snmp 31) counts GetRequest-, GetNextRequest-, GetBulkRequest-, SetRequest-, and InformRequest-PDUs silently dropped because the size of an alternate empty-varbindings Response-PDU would exceed either a local constraint or the originator's maximum message size.
snmpTrapEnterprise (snmpTrap 3) is an accessible-for-notify OBJECT IDENTIFIER carrying the enterprise OID associated with the trap. When a SNMPv2 proxy agent maps an RFC 1157 Trap-PDU into a SNMPv2-Trap-PDU, this variable appears as the last varbind.
snmpTrapOID (snmpTrap 1) is an accessible-for-notify OBJECT IDENTIFIER that carries the authoritative identification of the notification currently being sent; it occurs as the second varbind in every SNMPv2-Trap-PDU and InformRequest-PDU.
sysDescr (system 1) is a read-only DisplayString (0..255 octets) containing the full name and version identification of the system's hardware type, software operating-system, and networking software.
sysName (system 5) is a read-write DisplayString (0..255 octets) for an administratively-assigned name; by convention, this is the node's fully-qualified domain name. If unknown, the value is the zero-length string.
sysORLastChange (system 8) is a TimeStamp recording the value of sysUpTime at the time of the most recent change in state or value of any instance of sysORID, allowing managers to detect capability changes efficiently.
sysORTable (system 9) is a conceptual table advertising the MIB module capabilities of the local SNMPv2 agent. Each row (SysOREntry) contains sysORIndex, sysORID (capability OID), sysORDescr (text), and sysORUpTime (TimeStamp of row instantiation). Entities with dynamically-configurable MIB support will have a dynamically-varying number of rows.
sysServices (system 7) is a read-only INTEGER (0..127) encoding a bitmask of OSI layers supported: for layer L, the value 2^(L-1) is added to the sum, covering layers 1 (physical) through 7 (application).
sysUpTime (system 3) is a read-only TimeTicks object reporting the time in hundredths of a second since the network management portion of the system was last re-initialized.
The SNMP Group (mib-2 11) provides basic instrumentation of an SNMPv2 entity, including counters for received packets, bad versions, ASN.1 parse errors, silent drops, and proxy drops, as well as the snmpEnableAuthenTraps control object.
The System Group (mib-2 1) defines objects common to all managed systems, including sysDescr, sysObjectID, sysUpTime, sysContact, sysName, sysLocation, sysServices, and the sysORTable for capability advertisement.
warmStart (snmpTraps 2) is a NOTIFICATION-TYPE signifying that the SNMPv2 agent is reinitializing itself such that its configuration is unaltered.
The Security Considerations section of RFC 1907 explicitly states that security issues are not discussed in this memo, deferring security treatment entirely to other SNMPv2 framework documents.