Digital TCP/IP Services for OpenVMS
eSNMP Programming and Reference

3.4 Defining MIB-II Implemented Objects

• The system group --- The system (1) objects are discussed in Table 3-3.
• The interface group --- The interfaces (2) objects are discussed in Table 3-4.
• The address translation group --- The at (3) objects are discussed in Table 3-5.
• The Internet Protocol group --- The ip (4) objects are discussed in Table 3-6.
• The ICMP group --- The icmp (5) objects are discussed in Table 3-7.
• The TCP group --- The tcp (6) objects are discussed in Table 3-8.
• The UDP group --- The udp (7) objects are discussed in Table 3-9.
• The SNMP group --- The snmp (11) objects are discussed in Table 3-10.

Table 3-3 MIB-II System Group Objects

Object Name	Data Type	Access	RFC Description
sysDescr	DisplayString	Read only	A textual description of the entity, for example, hardware or operating system.
sysObjectID	Object Identifier	Read only	The vendor's authoritative identification of the network management subsystem contained in the entity.
sysUpTime	TimeTicks	Read only	The time, in hundredths of a second, since the network management portion of the system was last reinitialized.
sysContact	DisplayString	Read/write	The textual identification of the contact person responsible for this managed node.
sysName	DisplayString	Read/write	An administratively assigned name for this managed node.
sysLocation	DisplayString	Read/write	The physical location of this node.
sysServices	Integer	Read only	A value indicating the set of services that this entity primarily offers.

Table 3-4 MIB-II Interfaces Group Objects

Object Name	Data Type	Access	RFC Description
ifNumber	Integer	Read only	The number of network interfaces.
ifTable	Sequence of IfEntry	Not accessible	A list of interface entries.
ifEntry	IfEntry	Not accessible	An interface entry containing objects at the subnetwork layer and below for a particular interface.
ifIndex	Integer	Read only	A unique value for each interface.
ifDescr	DisplayString	Read only	Information about the interface, including name of manufacturer, product name, and version of the hardware interface.
ifType	Integer	Read only	Type of interface, distinguished according to the physical/link protocol(s).
ifMtu	Integer	Read only	The size of the largest datagram, in octets, that can be sent/received on the interface.
ifSpeed	Gauge	Read only	An estimate of the interface's current bandwidth capacity.
ifPhysAddress	PhysAddress	Read only	The interface's address at the protocol layer immediately below the Network layer.
ifAdminStatus	Integer	Read/write	Desired interface state: up (1); down (2); testing (3). The testing state indicates that no operational packets can be passed.
ifOperStatus	Integer	Read only	Current operational interface state: up (1); down (2); testing (3). The testing state indicates that no operational packets can be passed.
ifLastChange	TimeTicks	Read only	Value of sysUpTime at the time the interface entered its current operational state.
ifInOctets	Counter	Read only	Total number of octets received on the interface, including framing characters.
ifInUcastPkts	Counter	Read only	Number of subnetwork unicast packets delivered to a higher-layer protocol.
ifInNUcastPkts	Counter	Read only	Number of non-unicast packets delivered to a higher-layer protocol.
ifInDiscards	Counter	Read only	Number of inbound packets discarded even though no errors were detected. This prevents them from being delivered to a higher-layer protocol (for example, buffer overflow).
ifInErrors	Counter	Read only	Number of inbound packets that contain errors preventing them from being deliverable to a higher-layer protocol.
ifInUnknownProtos	Counter	Read only	Number of packets that were discarded because of an unknown or unsupported protocol.
ifOutOctets	Counter	Read only	Total number of octets transmitted on the interface, including framing characters.
ifOutUcastPkts	Counter	Read only	Total number of packets requested by higher-level protocols to be transmitted to a subnetwork- unicast address, including those that were discarded or otherwise not sent.
ifOutNUcastPkts	Counter	Read only	Total number of packets requested by higher-level protocols to be transmitted to a non-unicast address, including those that were discarded or otherwise not sent.
ifOutDiscards	Counter	Read only	Number of outbound packets discarded even though no errors were detected. This prevents them from being transmitted (for example, buffer overflow).
ifOutErrors	Counter	Read only	Number of outbound packets that could not be transmitted because of errors.
ifOutQLen	Gauge	Read only	Length of the output packet queue (in packets).
ifSpecific	Object Identifier	Read only	Reference to MIB definitions specific to the particular media being used to realize the interface.

Table 3-5 MIB-II Address Translation Group Objects

Object Name	Data Type	Access	RFC Description
atTable	Sequence of AtEntry	Not accessible	Contains the NetAddress to PhysAddress equivalent.
atEntry	AtEntry	Not accessible	Each entry contains one NetAddress to PhysAddress equivalent.
atIndex	Integer	Read/write	Interface on which this entry is effective.
atPhysAddress	PhysAddress	Read/write	Media-dependent physical address.
atNetAddress	NetAddress	Read/write	The NetAddress (for example, IP address) corresponding to the media-dependent physical address.

Table 3-6 MIB-II IP Group Objects

Object Name	Data Type	Access	RFC Description
ipForwarding	Integer	Read/write	If the value is (1), the entity is acting as an IP gateway (1). If the value is (2), the entity is not acting as an IP gateway.
ipDefaultTTL	Integer	Read/write	Default value inserted into time-to-live field of IP header of datagrams originated at this entity.
ipInReceives	Counter	Read only	Total number of input datagrams received from interfaces, including those received in error.
ipInDdrErrors	Counter		Number of input datagrams discarded due to errors in IP header.
ipAddrErrors	Counter	Read only	Number of input datagrams discarded because the IP address in the destination field was not valid for receipt at this entity.
ipForwDatagrams	Counter	Read only	Number of input datagrams for which this entity was not their final IP destination, a result of which an attempt was made to forward.
ipUnknownProtos	Counter	Read only	Number of locally addressed datagrams received successfully but discarded because of an unknown or unsupported protocol.
ipDiscards	Counter	Read only	Number of input datagrams for which no problems were encountered to prevent their continued processing but that were discarded (for example, for lack of buffer space).
ipDelivers	Counter	Read only	Total number of input Datagram successfully delivered to IP user protocols.
ipOutRequests	Counter	Read only	Total number of input datagrams that local IP user protocols supplied to IP in request for transmission.
ipOutDiscards	Counter	Read only	Number of output datagrams for which no problems were encountered to prevent transmission to their destination but were discarded (for example, for lack of buffer space).
ipOutNoRoutes	Counter	Read only	Number of IP datagrams discarded because no route could be found.
ipReasmTimeout	Integer	Read only	Maximum number of seconds that received fragments are held awaiting reassembly at this entity.
ipReasmReqds	Counter	Read only	Number of IP fragments received that needed to be reassembled at this entity.
ipReasmOKs	Counter	Read only	Number of IP datagrams successfully reassembled.
ipReasmFails	Counter	Read only	Number of failures detected by the IP reassembly algorithm.
ipFragOKs	Counter	Read only	Number of IP datagrams that have been successfully fragmented at this entity.
ipFragFails	Counter	Read only	Number of IP datagrams discarded because they needed to be fragmented at this entity but could not be because the do-not-fragment flag was set.
ipFragCreates	Counter	Read only	Number of IP datagram fragments generated at this entity.
ipAddrTable	Sequence of IpAddrEntry	Not accessible	Table of addressing information relevant to the IP address of this entity.
ipAddrEntry	IpAddrEntry	Not accessible	Addressing information for one of this entity's IP addresses.
ipAdEntAddr	IpAddress	Read only	IP address to which this entry's addressing information pertains.
ipAdEntIndex	Integer	Read only	Index value that uniquely identifies the interface to which this entry is applicable.
ipAdEntNetMask	IpAddress	Read only	Subnetwork mask associated with the IP address of this entity.
ipAdEntBcastAddr	Integer	Read only	Value of the least-significant bit in the IP broadcast address used for sending datagrams on the logical interface associated with the IP address of this entry.
ipAdEntReasmMaxSize	Integer	Read only	Size of the largest IP datagrams that this entity can reassemble from incoming IP fragmented datagrams received on this interface.
ipRouteTable	Sequence of IpRouteEntry	Not accessible	The IP routing table for this entity.
ipRouteEntry	IpRouteEntry	Not accessible	A route to a specific destination.
ipRouteDest	IpAddress	Read/write	The destination IP address of this route.
ipRouteIfIndex	Integer	Read/write	Index value that uniquely identifies the local interface through which the next hop of this route should be reached.
ipRouteMetric1	Integer	Read/write	Primary routing metric for this route.
ipRouteMetric2	Integer	Read/write	Alternate routing metric for this route.
ipRouteMetric3	Integer	Read/write	Alternate routing metric for this route.
ipRouteMetric4	Integer	Read/write	Alternate routing metric for this route.
ipRouteNextHop	IpAddress	Read/write	IP address of next hop of this route.
ipRouteType	Integer	Read/write	The type of route. The following values are valid for this entity: other (1); invalid (2); direct (3); indirect (4).
ipRouteProto	Integer	Read only	The routing mechanism via which this route was learned. The following values are valid for this entity: other (1); local (2); netmgmt (3); icmp (4); egp (5); ggp (6); hello (7); rip (8); is-is (9); es-is (10); ciscoIgrp (11); bbnSpfIgp (12); ospf (13); bgp (14).
ipRouteAge	Integer	Read/write	Number of seconds since this route was last updated or verified.
ipRouteMask	IpAddress	Read/write	Mask to be ANDed with destination address before being compared to ipRouteDest.
ipRouteMetric5	Integer	Read/write	Alternate routing metric for this route.
ipRouteInfo	Object Identifier	Read only	Reference to MIB definitions specific to the routing protocol responsible for this route.
ipNetToMediaTable	Sequence of IpNetToMediaEntry	Not accessible	IP address translation table used for mapping from IP addresses to physical addresses.
ipNetToMediaEntry	IpNetToMediaEntry	Not accessible	Each entry contains one IP address to physical address equivalent.
ipNetToMediaIfIndex	Integer	Read/write	Interface for which this entry's equivalence applies.
ipNetToMediaPhysAddress	PhysAddress	Read/write	Media-dependent physical address.
ipNetToMediaNetAddress	IpAddress	Read/write	IP address correspoding to the media-dependent physical address.
ipNetToMediaType	Integer	Read/write	Type of mapping: Other (1); invalid (2); dynamic (3); static (4).
ipRoutingDiscards	Counter	Read only	Number of routing entries discarded even though valid (for example, due to lack of buffer space).

Table 3-7 MIB-II ICMP Group Objects

Object Name	Data Type	Access	RFC Description
icmpInMsgs	Counter	Read only	Number of ICMP messages that the entity received.
icmpInErrors	Counter	Read only	Number of ICMP messages received but determined to have ICMP-specific errors.
icmpInDestUnreachs	Counter	Read only	Number of ICMP destination-unreachable messages received.
icmpInTimeExcds	Counter	Read only	Number of ICMP time-exceeded messages received.
icmpInParmProbs	Counter	Read only	Number of ICMP parameter-problem messages received.
icmpInSrcQuenchs	Counter	Read only	Number of ICMP source-quench messages received.
icmpInRedirects	Counter	Read only	Number of ICMP redirect messages received.
icmpInEchos	Counter	Read only	Number of ICMP echo-request messages received.
icmpInEchoReps	Counter	Read only	Number of ICMP echo-reply messages received.
icmpInTimestamps	Counter	Read only	Number of ICMP timestamp-request messages received.
icmpInTimestampReps	Counter	Read only	Number of ICMP timestamp-reply messages received.
icmpInAddrMasks	Counter	Read only	Number of ICMP address-mask-request messages received.
icmpInAddrMaskReps	Counter	Read only	Number of ICMP address-mask-reply messages received.
icmpOutMsgs	Counter	Read only	Total number of ICMP messages that the entity attempted to send.
icmpOutErrors	Counter	Read only	Number of ICMP messages that the entity did not send due to problems discovered within ICMP.
icmpOutDestUnreachs	Counter	Read only	Number of ICMP destination-unreachable messages sent.
icmpOutTimeExcds	Counter	Read only	Number of ICMP time-exceeded messages sent.
icmpOutParmProbs	Counter	Read only	Number of ICMP parameter-problem messages sent.
icmpOutSrcQuenchs	Counter	Read only	Number of ICMP source-quench messages sent.
icmpOutRedirects	Counter	Read only	Number of ICMP redirect messages sent.
icmpOutEchos	Counter	Read only	Number of ICMP echo-request messages sent.
icmpOutEchoReps	Counter	Read only	Number of ICMP echo-reply messages sent.
icmpOutTimestamps	Counter	Read only	Number of ICMP timestamp-request messages sent.
icmpOutTimestampReps	Counter	Read only	Number of ICMP timestamp-reply messages sent.
icmpOutAddrMasks	Counter	Read only	Number of ICMP address-mask-request messages sent.
icmpOutAddrMaskReps	Counter	Read only	Number of ICMP address-mask-reply messages sent.

Table 3-8 MIB-II TCP Group Objects

Object Name	Data Type	Access	RFC Description
tcpRtoAlgorithm	Integer	Read only	The algorithm used to determine the timeout value used for retransmitting unacknowledged octets. Retransmission time: other (1); constant (2); MIL-STD-1778 (3); Van Jacobson's algorithm (4).
tcpRtoMin	Integer	Read only	Minimum value for the retransmission timeout, measured in milliseconds.
tcpRtoMax	Integer	Read only	Maximum value for the retransmission timeout, measured in milliseconds.
tcpMaxConn	Integer	Read only	Limit on total number of TCP connections the entity can support.
tcpActiveOpens	Counter	Read only	Number of times TCP connections have made a direct transition to the SYN-SENT state from the CLOSED state.
tcpPassiveOpens	Counter	Read only	Number of times TCP connections have made a direct transition to the SYN-RCVD state from the LISTEN state.
tcpAttemptFails	Counter	Read only	Number of times TCP connections have made a direct transition to the CLOSED state from either the SYN-SENT state or the SYN-RCVD state. In addition, this includes number of times TCP connections have made a direct transition to the LISTEN state from the SYN-RCVD state.
tcpEstabResets	Counter	Read only	Number of times TCP connections have made a direct transition to the CLOSED state from either the ESTABLISHED state or the CLOSE-WAIT state.
tcpCurrEstab	Gauge	Read only	Number of TCP connections for which the current state is either ESTABLISHED or CLOSE-WAIT.
tcpInSegs	Counter	Read only	Total number of segments received, including those received in error.
tcpOutSegs	Counter	Read only	Total number of segments sent, excluding those containing only retransmitted octets.
tcpRetransSeg	Counter	Read only	Total number of retransmitted segments.
tcpConnTable	Sequence of TcpConnEntry	Not accessible	Contains TCP connection-specific information.
tcpConnEntry	TcpConnEntry	Not accessible	Information about a particular current TCP connection.
tcpConnState	Integer	Read/write	The state of this TCP connection closed (1), listen (2), synSent (3), synReceived (4), established (5), finWait1 (6), finWait2 (7), closeWait (8), lastAck (9), closing (10), timeWait (11), delete TCB (12).
tcpConnLocalAddress	IpAddress	Read only	Local IP address for this TCP connection.
tcpConnLocalPort	Integer	Read only	Local port number for this TCP connection.
tcpConnRemAddress	IpAddress	Read only	Remote IP address for this TCP connection.
tcpConnRemPort	Integer	Read only	Remote port number for this TCP connection.
tcpInErrs	Counter	Read only	Total number of segments received in error.
tcpOutRsts	Counter	Read only	Number of TCP segments sent containing the RST flag.

Table 3-9 MIB-II UDP Group Objects

Object Name	Data Type	Access	RFC Description
udpInDatagrams	Counter	Read only	Total number of UDP datagrams delivered to UDP users.
udpNoPorts	Counter	Read only	Total number of received UDP datagrams for which there was no application at the destination port.
udpInErrors	Counter	Read only	Number of received UDP datagrams that could not be delivered for reasons other than the lack of an application at the destination port.
udpOutDatagrams	Counter	Read only	Total number of UDP datagrams sent from this entity.
udpTable	Sequence of UdpEntry	Not accessible	Contains UDP listener information.
udpEntry	UdpEntry	Not accessible	Information about a particular current UDP listener.
udpLocalAddress	IpAddress	Read only	Local IP address for this UDP listener.
udpLocalPort	Integer	Read only	Local port number for this UDP listener.

Table 3-10 MIB-II SNMP Group Objects

Object Name	Data Type	Access	RFC Description
snmpInPkts	Counter	Read only	The total number of messages delivered to the SNMP entity from the transport service.
snmpOutPkts	Counter	Read only	The total number of SNMP messages passed from the SNMP protocol entity to the transport service.
snmpInBadVersions	Counter	Read only	The total number of SNMP messages delivered to the SNMP protocol entity that were for an unsupported version of SNMP.
snmpInBadCommunityNames	Counter	Read only	The total number of SNMP messages that used a community name unknown to the receiving SNMP protocol entity.
snmpInBadCommunityUses	Counter	Read only	The total number of SNMP messages delivered to the SNMP protocol entity that represented an SNMP operation that was not allowed by the SNMP community named in the message.
snmpInASNParseErrs	Counter	Read only	The total number of Abstract Syntax Notation One (ASN.1) or basic encoding rules (BER) language code errors encountered by the SNMP protocol entity when decoding received SNMP messages.
snmpInTooBigs	Counter	Read only	The total number of SNMP protocol data units (PDUs) delivered to the SNMP protocol entity for which the value of the error-status field is tooBig.
snmpInNoSuchName	Counter	Read only	The total number of SNMP PDUs delivered to the SNMP protocol entity for which the value of the error-status field is noSuchName.
snmpInBadValues	Counter	Read only	The total number of SNMP PDUs delivered to the SNMP protocol entity for which the value of the error-status field is badValue.
snmpInReadOnlys	Counter	Read only	The total number of valid SNMP PDUs delivered to the SNMP protocol entity for that the value of the error-status field is "Read only." It is a protocol error to generate an SNMP PDU that contains the value "Read only" in the error-status field. This object is provided as a means of detecting incorrect implementations of the SNMP.
snmpInGenErrs	Counter	Read only	The total number of SNMP PDUs delivered to the SNMP protocol entity for which the value of the error-status field is genErr.
snmpInTotalReqVars	Counter	Read only	The total number of MIB objects retrieved successfully by the SNMP protocol entity as the result of receiving valid SNMP Get-Request and Get-Next PDUs.
snmpInTotalSetVars	Counter	Read only	The total number of MIB objects altered successfully by the SNMP protocol entity as the result of receiving valid SNMP Set-Request PDUs.
snmpInGetRequests	Counter	Read only	The total number of SNMP Get-Request PDUs accepted and processed by the SNMP protocol entity.
snmpInGetNexts	Counter	Read only	The total number of SNMP Get-Next PDUs accepted and processed by the SNMP protocol entity.
snmpInSetRequests	Counter	Read only	The total number of SNMP Set-Request PDUs accepted and processed by the SNMP protocol entity.
snmpInGetResponses	Counter	Read only	The total number of SNMP Get-Response PDUs accepted and processed by the SNMP protocol entity.
snmpInTraps	Counter	Read only	The total number of SNMP Trap PDUs accepted and processed by the SNMP protocol entity.
snmpOutTooBigs	Counter	Read only	The total number of SNMP PDUs generated by the SNMP protocol entity and for which the value of the error-status field is tooBig.
snmpOutNoSuchNames	Counter	Read only	The total number of SNMP PDUs generated by the SNMP protocol entity and for which the value of the error-status is noSuchName.
snmpOutBadValues	Counter	Read only	The total number of SNMP PDUs generated by the SNMP protocol entity and for which the value of the error-status field is badValue.
snmpOutGenErrs	Counter	Read only	The total number of SNMP PDUs generated by the SNMP protocol entity and for which the value of the error-status field is genErr.
snmpOutGetRequests	Counter	Read only	The total number of SNMP Get-Request PDUs generated by the SNMP protocol entity.
snmpOutGetNexts	Counter	Read only	The total number of SNMP Get-Next PDUs generated by the SNMP protocol entity.
snmpOutSetRequests	Counter	Read only	The total number of SNMP Set-Request PDUs generated by the SNMP protocol entity.
snmpOutGetResponses	Counter	Read only	The total number of SNMP Get-Response PDUs generated by the SNMP protocol entity.
snmpOutTraps	Counter	Read only	The total number of SNMP Trap PDUs generated by the SNMP protocol entity.
snmpEnableAuthenTraps	Integer	Read only	Indicates whether the SNMP agent process is permitted to generate authentication-failure traps. The value of this object overrides any configuration information. For example, this entity provides a means to disable all authentication-failure traps. Digital strongly recommends that this object be stored in non-volatile memory so it remains constant between reinitializations of the network management system.

This chapter describes how to use the eSNMP API to create a MIB subagent that manages entities or applications. Topics included in this chapter are:

• Creating a MIB specification (Section 4.1)
• The structure of management information (Section 4.2)
• Creating a MIB source file (Section 4.3)
• Including the routines and building the subagent (Section 4.4)

Note

To use this eSNMP API to create a subagent, you must have a C compiler running on your host system.

The creation of a management information base (MIB) begins with data gathering. During this phase, the developer identifies the information to manage based on what entities the network manager needs to manipulate. After gathering the data, the developer uses Abstract Syntax Notation One (ASN.1) to specify the objects in the MIB.

4.2 The Structure of Management Information

The structure of management information (SMI), which is specified in RFC 1155, defines the general framework within which a MIB can be defined and constructed. The SMI framework identifies the data types that can be used in the MIB and how resources within the MIB are represented and named.