RFC 1158
Management Information Base for network management of TCP/IP-based internets: MIB-II
Network Working Group M. Rose, Editor Request for Comments: 1158 Performance Systems International May 1990 Management Information Base for Network Management of TCP/IP-based internets: MIB-II 1. Status of this Memo This memo defines the second version of the Management Information Base (MIB-II) for use with network management protocols in TCP/IP- based internets. In particular, together with its companion memos which describe the structure of management information (RFC 1155) along with the network management protocol (RFC 1157) for TCP/IP- based internets, these documents provide a simple, workable architecture and system for managing TCP/IP-based internets and in particular the Internet community. This document on MIB-II incorporates all of the technical content of RFC 1156 on MIB-I and extends it, without loss of compatibilty. However, MIB-I as described in RFC 1156 is full Standard Protocol of the Internet, while the MIB-II described here is Proposed Standard Protocol of the Internet. This memo defines a mandatory extension to the base MIB (RFC 1156) and is a Proposed Standard for the Internet community. The extensions described here are currently Elective, but when they become a standard, they will have the same status as RFC 1156, that is, Recommended. The Internet Activities Board recommends that all IP and TCP implementations be network manageable. This implies implementation of the Internet MIB (RFC 1156 and the extensions in RFC 1158) and at least one of the two recommended management protocols SNMP (RFC 1157) or CMOT (RFC 1095). This version of the MIB specification, MIB-II, is an incremental refinement of MIB-I. As such, it has been designed according to two criteria: first, changes have been made in response to new operational requirements in the Internet; and, second, the changes are entirely upwards compatible in order to minimize impact on the network as the managed nodes in the Internet transition from MIB-I to MIB-II. It is expected that additional MIB groups and variables will be defined over time to accommodate the monitoring and control needs of new or changing components of the Internet.
Please refer to the latest edition of the "IAB Official Protocol
Standards" RFC for current information on the state and status of
standard Internet protocols.
Distribution of this memo is unlimited.
Table of Contents
1. Status of this Memo .................................. 1
2. Introduction ......................................... 3
3. Changes from MIB-I ................................... 4
3.1 Deprecated Objects .................................. 4
3.2 Display Strings ..................................... 5
3.3 The System Group .................................... 5
3.4 The Interfaces Group ................................ 5
3.5 The Address Translation Group ....................... 6
3.6 The IP Group ........................................ 7
3.7 The ICMP Group ...................................... 7
3.8 The TCP Group ....................................... 7
3.9 The UDP Group ....................................... 7
3.10 The EGP Group ...................................... 8
3.11 The Transmission Group ............................. 8
3.12 The SNMP Group ..................................... 8
4. Objects .............................................. 8
4.1 Object Groups ....................................... 9
4.2 Format of Definitions ............................... 10
5. Object Definitions ................................... 10
5.1 The System Group .................................... 11
5.2 The Interfaces Group ................................ 14
5.2.1 The Interfaces table .............................. 15
5.3 The Address Translation Group ....................... 27
5.4 The IP Group ........................................ 30
5.4.1 The IP Address table .............................. 38
5.4.2 The IP Routing table .............................. 41
5.4.3 The IP Address Translation table .................. 48
5.5 The ICMP Group ...................................... 51
5.6 The TCP Group ....................................... 61
5.6.1 The TCP Connection table .......................... 66
5.6.2 Additional TCP Objects ............................ 69
5.7 The UDP Group ....................................... 70
5.7.1 The UDP Listener table ............................ 72
5.8 The EGP Group ....................................... 73
5.8.1 The EGP Neighbor table ............................ 75
5.8.2 Additional EGP variables .......................... 83
5.9 The Transmission Group .............................. 83
5.10 The SNMP Group ..................................... 83
6. Definitions .......................................... 95
7. Identification of OBJECT instances for use with the
SNMP ................................................. 126
7.1 ifTable Object Type Names ........................... 127
7.2 atTable Object Type Names ........................... 127
7.3 ipAddrTable Object Type Names ....................... 128
7.4 ipRoutingTable Object Type Names .................... 128
7.5 ipNetToMediaTable Object Type Names ................. 129
7.6 tcpConnTable Object Type Names ...................... 129
7.7 udpTable Object Type Names .......................... 130
7.8 egpNeighTable Object Type Names ..................... 130
8. Acknowledgements .................................... 130
9. References .......................................... 131
10. Security Considerations.............................. 133
11. Author's Address..................................... 133
2. Introduction
As reported in RFC 1052, IAB Recommendations for the
Development of Internet Network Management Standards [1], a
two-prong strategy for network management of TCP/IP-based
internets was undertaken. In the short-term, the Simple
Network Management Protocol (SNMP) was to be used to manage
nodes in the Internet community. In the long-term, the use of
the OSI network management framework was to be examined. Two
documents were produced to define the management information:
RFC 1065, which defined the Structure of Management
Information (SMI) [2], and RFC 1066, which defined the
Management Information Base (MIB) [3]. Both of these
documents were designed so as to be compatible with both the
SNMP and the OSI network management framework.
This strategy was quite successful in the short-term:
Internet-based network management technology was fielded, by
both the research and commercial communities, within a few
months. As a result of this, portions of the Internet
community became network manageable in a timely fashion.
As reported in RFC 1109, Report of the Second Ad Hoc Network
Management Review Group [4], the requirements of the SNMP and
the OSI network management frameworks were more different than
anticipated. As such, the requirement for compatibility
between the SMI/MIB and both frameworks was suspended. This
action permitted the operational network management framework,
the SNMP, to respond to new operational needs in the Internet
community by producing this document.
As such, the current network management framework for TCP/IP-
based internets consists of: Structure and Identification of
Management Information for TCP/IP-based internets, RFC 1155 [13], which describes how managed objects contained in the MIB are defined; Management Information Base for Network Management of TCP/IP-based internets (version 2), this memo, which describes the managed objects contained in the MIB; and, the Simple Network Management Protocol, RFC 1157 [14], which defines the protocol used to manage these objects. Consistent with the IAB directive to produce simple, workable systems in the short-term, the list ofc objects (e.g., for BSD UNIX) were excluded. 7) It was agreed to avoid heavily instrumenting critical sections of code. The general guideline was one counter per critical section per layer. 3. Changes from MIB-I Features of this MIB include: 1) incremental additions to reflect new operational requirements; 2) upwards compatibility with the SMI/MIB and the SNMP; 3) improved support for multi-protocol entities; and, 4) textual clean-up of the MIB to improve clarity and readability. The objects defined in MIB-II have the OBJECT IDENTIFIER prefix: mib-2 OBJECT IDENTIFIER ::= { mgmt 1 } 3.1. Deprecated Objects In order to better prepare implementors for future changes in the MIB, a new term "deprecated" may be used when describing an object. A deprecated object in the MIB is one which must be supported, but one which will most likely be removed from the next version of the MIB (e.g., MIB-III). MIB-II marks one object as being deprecated: atTable As a result of deprecating the atTable object, the entire Address Translation group is deprecated.
Note that no functionality is lost with the deprecation of these objects: new objects providing equivalent or superior functionality are defined in MIB-II. 3.2. Display Strings In the past, there have been misinterpretations of the MIB as to when a string of octets should contain printable characters, meant to be displayed to a human. As a textual convention in the MIB, the datatype DisplayString ::= OCTET STRING is introduced. A DisplayString is restricted to the NVT ASCII character set, as defined in pages 10-11 of [7]. The following objects are now defined in terms of DisplayString: sysDescr ifDescr It should be noted that this change has no effect on either the syntax nor semantics of these objects. The use of the DisplayString notation is merely an artifact of the explanatory method used in MIB-II and future MIBs. Further, it should be noted that any object defined in terms of OCTET STRING may contain arbitrary binary data, in which each octet may take any value from 0 to 255 (decimal). 3.3. The System Group Four new objects are added to this group: sysContact sysName sysLocation sysServices These provide contact, administrative, location, and service information regarding the managed node. 3.4. The Interfaces Group The definition of the ifNumber object was incorrect, as it required all interfaces to support IP. (For example, devices without IP, such as MAC-layer bridges, could not be managed if this definition was strictly followed.) The description of the ifNumber object is changed
accordingly.
The ifTable object was mistaken marked as read-write, it has been
(correctly) re-designated as read-only. In addition, several new
values have been added to the ifType column in the ifTable object:
ppp(23)
softwareLoopback(24)
eon(25)
ethernet-3Mbit(26)
nsip(27)
slip(28)
Finally, a new column has been added to the ifTable object:
ifSpecific
which provides information about information specific to the media
being used to realize the interface.
3.5. The Address Translation Group
In MIB-I, this group contained a table which permitted mappings from
network addresses (e.g., IP addresses) to physical addresses (e.g.,
MAC addresses). Experience has shown that efficient implementations
of this table make two assumptions: a single network protocol
environment, and mappings occur only from network address to physical
address.
The need to support multi-protocol nodes (e.g., those with both the
IP and CLNP active), and the need to support the inverse mapping
(e.g., for ES-IS), have invalidated both of these assumptions. As
such, the atTable object is declared deprecated.
In order to meet both the multi-protocol and inverse mapping
requirements, MIB-II and its successors will allocate up to two
address translation tables inside each network protocol group. That
is, the IP group will contain one address translation table, for
going from IP addresses to physical addresses. Similarly, when a
document defining MIB objects for the CLNP is produced (e.g., [8]),
it will contain two tables, for mappings in both directions, as this
is required for full functionality.
It should be noted that the choice of two tables (one for each
direction of mapping) provides for ease of implementation in many
cases, and does not introduce undue burden on implementations which
realize the address translation abstraction through a single internal
table.
3.6. The IP Group The access attribute of the variable ipForwarding has been changed from read-only to read-write. In addition, there is a new column to the ipAddrTable object, ipAdEntReasmMaxSize which keeps track of the largest IP datagram that can be re- assembled on a particular interface. There is also a new column in the ipRoutingTable object, ipRouteMask which is used for IP routing subsystems that support arbitrary subnet masks. One new object is added to the IP group: ipNetToMediaTable which is the address translation table for the IP group (providing identical functionality to the now deprecated atTable in the address translation group). 3.7. The ICMP Group There are no changes to this group. 3.8. The TCP Group Two new variables are added: tcpInErrs tcpOutRsts which keep track of the number of incoming TCP segments in error and the number of resets generated by a TCP. 3.9. The UDP Group A new table: udpTable is added.
3.10. The EGP Group Experience has indicated a need for additional objects that are useful in EGP monitoring. In addition to making several additions to the egpNeighborTable object, a new variable is added: egpAs which gives the autonomous system associated with this EGP entity. 3.11. The Transmission Group MIB-I was lacking in that it did not distinguish between different types of transmission media. A new group, the Transmission group, is allocated for this purpose: transmission OBJECT IDENTIFIER ::= { mib-2 10 } When Internet-standard definitions for managing transmission media are defined, the transmission group is used to provide a prefix for the names of those objects. Typically, such definitions reside in the experimental portion of the MIB until they are "proven", then as a part of the Internet standardization process, the definitions are accordingly elevated and a new object identifier, under the transmission group is defined. By convention, the name assigned is: type OBJECT IDENTIFIER ::= { transmission number } where "type" is the symbolic value used for the media in the ifType column of the ifTable object, and "number" is the actual integer value corresponding to the symbol. 3.12. The SNMP Group The application-oriented working groups of the IETF have been tasked to be receptive towards defining MIB variables specific to their respective applications. For the SNMP, it is useful to have statistical information. A new group, the SNMP group, is allocated for this purpose: snmp OBJECT IDENTIFIER ::= { mib-2 11 } 4. Objects Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. Objects in the MIB are defined using Abstract Syntax Notation One (ASN.1) [9]. The mechanisms used for describing these objects are specified the companion memo, the SMI. In particular, each object has a name, a syntax, and an encoding. The name is an object identifier, an administratively assigned name, which specifies an object type. The object type together with an object instance serves to uniquely identify a specific instantiation of the object. For human convenience, we often use a textual string, termed the OBJECT DESCRIPTOR, to also refer to the object type. The syntax of an object type defines the abstract data structure corresponding to that object type. The ASN.1 language is used for this purpose. However, the companion memo purposely restricts the ASN.1 constructs which may be used. These restrictions are explicitly made for simplicity. The encoding of an object type is simply how that object type is represented using the object type's syntax. Implicitly tied to the notion of an object type's syntax and encoding is how the object type is represented when being transmitted on the network. This memo specifies the use of the basic encoding rules (BER) of ASN.1 [10], subject to the additional requirements imposed by the SNMP [14]. 4.1. Object Groups Since this list of managed objects contains only the essential elements, there is no need to allow individual objects to be optional. Rather, the objects are arranged into the following groups: - System - Interfaces - Address Translation (deprecated) - IP - ICMP - TCP - UDP - EGP - Transmission - SNMP There are two reasons for defining these groups: to provide a means of assigning object identifiers; and, to provide a method for implementations of managed agents to know which objects they must implement. This method is as follows: if the semantics of a group is applicable to an implementation, then it must implement all objects
in that group. For example, an implementation must implement the EGP group if and only if it implements the EGP. 4.2. Format of Definitions The next section contains the specification of all object types contained in the MIB. Following the conventions of the companion memo, the object types are defined using the following fields: OBJECT: ------- A textual name, termed the OBJECT DESCRIPTOR, for the object type, along with its corresponding OBJECT IDENTIFIER. Syntax: The abstract syntax for the object type, presented using ASN.1. This must resolve to an instance of the ASN.1 type ObjectSyntax defined in the SMI. Definition: A textual description of the semantics of the object type. Implementations should ensure that their interpretation of the object type fulfills this definition since this MIB is intended for use in multi- vendor environments. As such it is vital that object types have consistent meaning across all machines. Access: A keyword, one of read-only, read-write, write-only, or not-accessible. Note that this designation specifies the minimum level of support required. As a local matter, implementations may support other access types (e.g., an implementation may elect to permitting writing a variable marked herein as read-only). Further, protocol-specific "views" (e.g., those implied by an SNMP community) may make further restrictions on access to a variable. Status: A keyword, one of mandatory, optional, obsolete, or deprecated. Use of deprecated implies mandatory status. 5. Object Definitions RFC1158-MIB DEFINITIONS ::= BEGIN
IMPORTS
mgmt, OBJECT-TYPE, NetworkAddress, IpAddress,
Counter, Gauge, TimeTicks
FROM RFC1155-SMI;
DisplayString ::=
OCTET STRING
mib-2 OBJECT IDENTIFIER ::= { mgmt 1 } -- MIB-II
system OBJECT IDENTIFIER ::= { mib-2 1 }
interfaces OBJECT IDENTIFIER ::= { mib-2 2 }
at OBJECT IDENTIFIER ::= { mib-2 3 }
ip OBJECT IDENTIFIER ::= { mib-2 4 }
icmp OBJECT IDENTIFIER ::= { mib-2 5 }
tcp OBJECT IDENTIFIER ::= { mib-2 6 }
udp OBJECT IDENTIFIER ::= { mib-2 7 }
egp OBJECT IDENTIFIER ::= { mib-2 8 }
-- cmot OBJECT IDENTIFIER ::= { mib-2 9 }
transmission OBJECT IDENTIFIER ::= { mib-2 10 }
snmp OBJECT IDENTIFIER ::= { mib-2 11 }
END
5.1. The System Group
Implementation of the System group is mandatory for all systems.
OBJECT:
-------
sysDescr { system 1 }
Syntax:
DisplayString (SIZE (0..255))
Definition:
A textual description of the entity. This value should
include the full name and version identification of the
system's hardware type, software operating-system, and
networking software. It is mandatory that this only
contain printable ASCII characters.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
sysObjectID { system 2 }
Syntax:
OBJECT IDENTIFIER
Definition:
The vendor's authoritative identification of the network
management subsystem contained in the entity. This value
is allocated within the SMI enterprises subtree
(1.3.6.1.4.1) and provides an easy and unambiguous means
for determining "what kind of box" is being managed. For
example, if vendor "Flintstones, Inc." was assigned the
subtree 1.3.6.1.4.1.4242, it could assign the identifier
1.3.6.1.4.1.4242.1.1 to its "Fred Router".
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
sysUpTime { system 3 }
Syntax:
TimeTicks
Definition:
The time (in hundredths of a second) since the network
management portion of the system was last re-initialized.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
sysContact { system 4 }
Syntax:
DisplayString (SIZE (0..255))
Definition:
The textual identification of the contact person for this
managed node, together with information on how to contact
this person.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
sysName { system 5 }
Syntax:
DisplayString (SIZE (0..255))
Definition:
An administratively-assigned name for this managed node.
By convention, this is the node's fully-qualified domain
name.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
sysLocation { system 6 }
Syntax:
DisplayString (SIZE (0..255))
Definition:
The physical location of this node (e.g., "telephone
closet, 3rd floor").
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
sysServices { system 7 }
Syntax:
INTEGER (0..127)
Definition:
A value which indicates the set of services that this
entity potentially offers. The value is a sum. This
sum initially takes the value zero, Then, for each layer,
L, in the range 1 through 7, that this node performs
transactions for, 2 raised to (L - 1) is added to the
sum. For example, a node which performs only routing
functions would have a value of 4 (2^(3-1)). In
contrast, a node which is a host offering application
services would have a value of 72 (2^(4-1) + 2^(7-1)).
Note that in the context of the Internet suite of
protocols, values should be calculated accordingly:
layer functionality
1 physical (e.g., repeaters)
2 datalink/subnetwork (e.g., bridges)
3 internet (e.g., supports the IP)
4 end-to-end (e.g., supports the TCP)
7 applications (e.g., supports the SMTP)
For systems including OSI protocols, layers 5 and 6 may
also be counted.
Access:
read-only.
Status:
mandatory.
5.2. The Interfaces Group
Implementation of the Interfaces group is mandatory for all systems.
OBJECT:
-------
ifNumber { interfaces 1 }
Syntax:
INTEGER
Definition:
The number of network interfaces (regardless of their
current state) present on this system.
Access:
read-only.
Status:
mandatory.
5.2.1. The Interfaces table
The Interfaces table contains information on the entity's interfaces.
Each interface is thought of as being attached to a "subnetwork".
Note that this term should not be confused with "subnet" which refers
to an addressing partitioning scheme used in the Internet suite of
protocols.
OBJECT:
-------
ifTable { interfaces 2 }
Syntax:
SEQUENCE OF IfEntry
Definition:
A list of interface entries. The number of entries is
given by the value of ifNumber.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifEntry { ifTable 1 }
Syntax:
IfEntry ::= SEQUENCE {
ifIndex
INTEGER,
ifDescr
DisplayString,
ifType
INTEGER,
ifMtu
INTEGER,
ifSpeed
Gauge,
ifPhysAddress
OCTET STRING,
ifAdminStatus
INTEGER,
ifOperStatus
INTEGER,
ifLastChange
TimeTicks,
ifInOctets
Counter,
ifInUcastPkts
Counter,
ifInNUcastPkts
Counter,
ifInDiscards
Counter,
ifInErrors
Counter,
ifInUnknownProtos
Counter,
ifOutOctets
Counter,
ifOutUcastPkts
Counter,
ifOutNUcastPkts
Counter,
ifOutDiscards
Counter,
ifOutErrors
Counter,
ifOutQLen
Gauge,
ifSpecific
OBJECT IDENTIFIER
}
Definition:
An interface entry containing objects at the subnetwork
layer and below for a particular interface.
Access:
read-only.
Status:
mandatory.
We now consider the individual components of each interface
entry:
OBJECT:
-------
ifIndex { ifEntry 1 }
Syntax:
INTEGER
Definition:
A unique value for each interface. Its value ranges
between 1 and the value of ifNumber. The value for each
interface must remain constant at least from one re-
initialization of the entity's network management system
to the next re-initialization.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifDescr { ifEntry 2 }
Syntax:
DisplayString (SIZE (0..255))
Definition:
A textual string containing information about the
interface. This string should include the name of the
manufacturer, the product name and the version of the
hardware interface.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifType { ifEntry 3 }
Syntax:
INTEGER {
other(1), -- none of the following
regular1822(2),
hdh1822(3),
ddn-x25(4),
rfc877-x25(5),
ethernet-csmacd(6),
iso88023-csmacd(7),
iso88024-tokenBus(8),
iso88025-tokenRing(9),
iso88026-man(10),
starLan(11),
proteon-10Mbit(12),
proteon-80Mbit(13),
hyperchannel(14),
fddi(15),
lapb(16),
sdlc(17),
t1-carrier(18),
cept(19), -- european equivalent of T-1
basicISDN(20),
primaryISDN(21),
-- proprietary serial
propPointToPointSerial(22),
ppp(23),
softwareLoopback(24),
eon(25), -- CLNP over IP [12]
ethernet-3Mbit(26)
nsip(27), -- XNS over IP
slip(28) -- generic SLIP
}
Definition:
The type of interface, distinguished according to the
physical/link protocol(s) immediately "below" the network
layer in the protocol stack.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifMtu { ifEntry 4 }
Syntax:
INTEGER
Definition:
The size of the largest datagram which can be
sent/received on the interface, specified in octets. For
interfaces that are used for transmitting network
datagrams, this is the size of the largest network
datagram that can be sent on the interface.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifSpeed { ifEntry 5 }
Syntax:
Gauge
Definition:
An estimate of the interface's current bandwidth in bits
per second. For interfaces which do not vary in
bandwidth or for those where no accurate estimation can
be made, this object should contain the nominal
bandwidth.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifPhysAddress { ifEntry 6 }
Syntax:
OCTET STRING
Definition:
The interface's address at the protocol layer immediately
"below" the network layer in the protocol stack. For
interfaces which do not have such an address (e.g., a
serial line), this object should contain an octet string
of zero length.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifAdminStatus { ifEntry 7 }
Syntax:
INTEGER {
up(1), -- ready to pass packets
down(2),
testing(3) -- in some test mode
}
Definition:
The desired state of the interface. The testing(3) state
indicates that no operational packets can be passed.
Access:
read-write.
Status:
mandatory.
OBJECT:
-------
ifOperStatus { ifEntry 8 }
Syntax:
INTEGER {
up(1), -- ready to pass packets
down(2),
testing(3) -- in some test mode
}
Definition:
The current operational state of the interface. The
testing(3) state indicates that no operational packets
can be passed.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifLastChange { ifEntry 9 }
Syntax:
TimeTicks
Definition:
The value of sysUpTime at the time the interface entered
its current operational state. If the current state was
entered prior to the last re-initialization of the local
network management subsystem, then this object contains a
zero value.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifInOctets { ifEntry 10 }
Syntax:
Counter
Definition:
The total number of octets received on the interface,
including framing characters.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifInUcastPkts { ifEntry 11 }
Syntax:
Counter
Definition:
The number of subnetwork-unicast packets delivered to a
higher-layer protocol.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifInNUcastPkts { ifEntry 12 }
Syntax:
Counter
Definition:
The number of non-unicast (i.e., subnetwork-broadcast or
subnetwork-multicast) packets delivered to a higher-layer
protocol.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifInDiscards { ifEntry 13 }
Syntax:
Counter
Definition:
The number of inbound packets which were chosen to be
discarded even though no errors had been detected to
prevent their being deliverable to a higher-layer
protocol. One possible reason for discarding such a
packet could be to free up buffer space.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifInErrors { ifEntry 14 }
Syntax:
Counter
Definition:
The number of inbound packets that contained errors
preventing them from being deliverable to a higher-layer
protocol.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifInUnknownProtos { ifEntry 15 }
Syntax:
Counter
Definition:
The number of packets received via the interface which
were discarded because of an unknown or unsupported
protocol.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifOutOctets { ifEntry 16 }
Syntax:
Counter
Definition:
The total number of octets transmitted out of the
interface, including framing characters.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifOutUcastPkts { ifEntry 17 }
Syntax:
Counter
Definition:
The total number of packets that higher-level protocols
requested be transmitted to a subnetwork-unicast address,
including those that were discarded or not sent.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifOutNUcastPkts { ifEntry 18 }
Syntax:
Counter
Definition:
The total number of packets that higher-level protocols
requested be transmitted to a non-unicast (i.e., a
subnetwork-broadcast or subnetwork-multicast) address,
including those that were discarded or not sent.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifOutDiscards { ifEntry 19 }
Syntax:
Counter
Definition:
The number of outbound packets which were chosen to be
discarded even though no errors had been detected to
prevent their being transmitted. One possible reason for
discarding such a packet could be to free up buffer
space.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifOutErrors { ifEntry 20 }
Syntax:
Counter
Definition:
The number of outbound packets that could not be
transmitted because of errors.
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifOutQLen { ifEntry 21 }
Syntax:
Gauge
Definition:
The length of the output packet queue (in packets).
Access:
read-only.
Status:
mandatory.
OBJECT:
-------
ifSpecific { ifEntry 22 }
Syntax:
OBJECT IDENTIFIER
Definition:
A reference to MIB definitions specific to the particular
media being used to realize the interface. For example,
if the interface is realized by an ethernet, then the
value of this object refers to a document defining
objects specific to ethernet. If an agent is not
configured to have a value for any of these variables,
the object identifier
nullSpecific OBJECT IDENTIFIER ::= { 0 0 }
is returned. Note that "nullSpecific" is a syntatically
valid object identifier, and any conformant
implementation of ASN.1 and BER must be able to generate
and recognize this value.
Access:
read-only.
Status:
mandatory.
(page 27 continued on part 2)
