Network Working Group F. Kastenholz Request for Comments: 1643 FTP Software, Inc. Obsoletes: 1623, 1398 July 1994 STD: 50 Category: Standards Track
Definitions of Managed Objects for the Ethernet-like Interface Types
Status of this Memo
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in the Internet community. In particular, it defines objects for managing ethernet-like objects.
This memo also includes a MIB module. This MIB module corrects minor errors in the earlier versions of this MIB: RFC 1623 [20], and RFC 1398 [15].
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1. The SNMP Network Management Framework
The SNMP Network Management Framework consists of three major components. They are:
o STD 16/RFC 1155 [3] which defines the SMI, the mechanisms used for describing and naming objects for the purpose of management. STD 16/RFC 1212 [13] defines a more concise description mechanism, which is wholly consistent with the SMI.
o RFC 1156 [4] which defines MIB-I, the core set of managed objects for the Internet suite of protocols. STD 17/RFC 1213 [6] defines MIB-II, an evolution of MIB-I based on implementation experience and new operational requirements.
o STD 15/RFC 1157 [5] which defines the SNMP, the protocol used for network access to managed objects.
The Framework permits new objects to be defined for the purpose of experimentation and evaluation.
1.1. Object Definitions
Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. Objects in the MIB are defined using the subset of Abstract Syntax Notation One (ASN.1) [7] defined in the SMI [16]. In particular, each object object type is named by an OBJECT IDENTIFIER, an administratively assigned name. 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 descriptor, to refer to the object type.
2. Change Log
This section enumerates changes made to RFC 1398 to produce this document.
(1) A section describing the applicability of various parts of RFC 1573 to ethernet-like interfaces has been added.
(2) A minor error in the description of the TDR test was fixed.
(3) A loopback test was defined to replace the standard loopback test that was defined in RFC 1229.
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(4) The description of dot3CollFrequencies was made a bit clearer.
(5) A new object, EtherChipset, has been added. This object replaces the ifExtnsChipSet object, which has been removed per the Interface MIB Evolution effort.
(6) Several minor editorial changes, spelling corrections, grammar and punctuation corrections, and so forth, were made.
3. Overview
Instances of these object types represent attributes of an interface to an ethernet-like communications medium. At present, ethernet-like media are identified by three values of the ifType object in the Internet-standard MIB:
ethernet-csmacd(6) iso88023-csmacd(7) starLan(11)
For these interfaces, the value of the ifSpecific variable in the MIB-II [6] has the OBJECT IDENTIFIER value:
dot3 OBJECT IDENTIFER ::= { transmission 7 }
The definitions presented here are based on the IEEE 802.3 Layer Management Specification [9], as originally interpreted by Frank Kastenholz then of Interlan in [10]. Implementors of these MIB objects should note that the IEEE document explicitly describes (in the form of Pascal pseudocode) when, where, and how various MAC attributes are measured. The IEEE document also describes the effects of MAC actions that may be invoked by manipulating instances of the MIB objects defined here.
To the extent that some of the attributes defined in [9] are represented by previously defined objects in the Internet-standard MIB or in the Generic Interface Extensions MIB [11], such attributes are not redundantly represented by objects defined in this memo. Among the attributes represented by objects defined in other memos are the number of octets transmitted or received on a particular interface, the number of frames transmitted or received on a particular interface, the promiscuous status of an interface, the MAC address of an interface, and multicast information associated with an interface.
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3.1. Relation to RFC 1213
This section applies only when this MIB is used in conjunction with the "old" (i.e., pre-RFC 1573) interface group.
The relationship between an ethernet-like interface and an interface in the context of the Internet-standard MIB is one-to-one. As such, the value of an ifIndex object instance can be directly used to identify corresponding instances of the objects defined herein.
3.2. Relation to RFC 1573
RFC 1573, the Interface MIB Evolution, requires that any MIB which is an adjunct of the Interface MIB, clarify specific areas within the Interface MIB. These areas were intentionally left vague in RFC 1573 to avoid over constraining the MIB, thereby precluding management of certain media-types.
Section 3.3 of RFC 1573 enumerates several areas which a media- specific MIB must clarify. Each of these areas is addressed in a following subsection. The implementor is referred to RFC 1573 in order to understand the general intent of these areas.
3.2.1. Layering Model
This MIB does not provide for layering. There are no sublayers.
EDITOR'S NOTE:
I could forsee the development of an 802.2 and enet-transceiver MIB. They could be higher and lower sublayers, respectively. All that THIS document should do is allude to the possibilities and urge the implementor to be aware of the possibility and that they may have requirements which supersede the requirements in this document.
3.2.2. Virtual Circuits
This medium does not support virtual circuits and this area is not applicable to this MIB.
3.2.3. ifTestTable
This MIB defines two tests for media which are instumented with this MIB; TDR and Loopback. Implementation of these tests is not required. Many common interface chips do not support one or both of these tests.
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These two tests are provided as a convenience, allowing a common method to invoke the test.
Standard MIBs do not include objects in which to return the results of the TDR test. Any needed objects MUST be provided in the vendor specific MIB.
3.2.4. ifRcvAddressTable
This table contains all IEEE 802.3 addresses, unicast, multicast, and broadcast, for which this interface will receive packets and forward them up to a higher layer entity for local consumption. The format of the address, contained in ifRcvAddressAddress, is the same as for ifPhysAddress.
In the event that the interface is part of a MAC bridge, this table does not include unicast addresses which are accepted for possible forwarding out some other port. This table is explicitly not intended to provide a bridge address filtering mechanism.
3.2.5. ifPhysAddress
This object contains the IEEE 802.3 address which is placed in the source-address field of any Ethernet, Starlan, or IEEE 802.3 frames that originate at this interface. Usually this will be kept in ROM on the interface hardware. Some systems may set this address via software.
In a system where there are several such addresses the designer has a tougher choice. The address chosen should be the one most likely to be of use to network management (e.g. the address placed in ARP responses for systems which are primarily IP systems).
If the designer truly can not chose, use of the factory- provided ROM address is suggested.
If the address can not be determined, an octet string of zero length should be returned.
The address is stored in binary in this object. The address is stored in "canonical" bit order, that is, the Group Bit is positioned as the low-order bit of the first octet. Thus, the first byte of a multicast address would have the bit 0x01 set.
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3.2.6. ifType
This MIB applies to interfaces which have any of the following three ifType values:
ethernet-csmacd(6) iso88023-csmacd(7) starLan(11)
Interfaces with any of these ifType values map to the EtherLike-MIB in the same manner. The EtherLike-MIB applies equally to all three types; there are no implementation differences.
4. Definitions
EtherLike-MIB DEFINITIONS ::= BEGIN
IMPORTS Counter, Gauge FROM RFC1155-SMI ifIndex, transmission FROM RFC1213-MIB OBJECT-TYPE FROM RFC-1212;
-- This MIB module uses the extended OBJECT-TYPE macro as -- defined in RFC-1212.
dot3 OBJECT IDENTIFIER ::= { transmission 7 }
-- the Ethernet-like Statistics group
dot3StatsTable OBJECT-TYPE SYNTAX SEQUENCE OF Dot3StatsEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "Statistics for a collection of ethernet-like interfaces attached to a particular system." ::= { dot3 2 }
dot3StatsEntry OBJECT-TYPE SYNTAX Dot3StatsEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "Statistics for a particular interface to an ethernet-like medium." INDEX { dot3StatsIndex } ::= { dot3StatsTable 1 }
dot3StatsIndex OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION "An index value that uniquely identifies an interface to an ethernet-like medium. The interface identified by a particular value of this index is the same interface as identified by the same value of ifIndex." ::= { dot3StatsEntry 1 }
dot3StatsAlignmentErrors OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "A count of frames received on a particular interface that are not an integral number of octets in length and do not pass the FCS check.
The count represented by an instance of this object is incremented when the alignmentError status is returned by the MAC service to the LLC (or other MAC user). Received frames for which multiple error conditions obtain are, according to the conventions of IEEE 802.3 Layer Management, counted exclusively according to the error status presented to the LLC." REFERENCE "IEEE 802.3 Layer Management"
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::= { dot3StatsEntry 2 }
dot3StatsFCSErrors OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "A count of frames received on a particular interface that are an integral number of octets in length but do not pass the FCS check.
The count represented by an instance of this object is incremented when the frameCheckError status is returned by the MAC service to the LLC (or other MAC user). Received frames for which multiple error conditions obtain are, according to the conventions of IEEE 802.3 Layer Management, counted exclusively according to the error status presented to the LLC." REFERENCE "IEEE 802.3 Layer Management" ::= { dot3StatsEntry 3 }
dot3StatsSingleCollisionFrames OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "A count of successfully transmitted frames on a particular interface for which transmission is inhibited by exactly one collision.
A frame that is counted by an instance of this object is also counted by the corresponding instance of either the ifOutUcastPkts, ifOutMulticastPkts, or ifOutBroadcastPkts, and is not counted by the corresponding instance of the dot3StatsMultipleCollisionFrames object." REFERENCE "IEEE 802.3 Layer Management" ::= { dot3StatsEntry 4 }
dot3StatsMultipleCollisionFrames OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION
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"A count of successfully transmitted frames on a particular interface for which transmission is inhibited by more than one collision.
A frame that is counted by an instance of this object is also counted by the corresponding instance of either the ifOutUcastPkts, ifOutMulticastPkts, or ifOutBroadcastPkts, and is not counted by the corresponding instance of the dot3StatsSingleCollisionFrames object." REFERENCE "IEEE 802.3 Layer Management" ::= { dot3StatsEntry 5 }
dot3StatsSQETestErrors OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "A count of times that the SQE TEST ERROR message is generated by the PLS sublayer for a particular interface. The SQE TEST ERROR message is defined in section 7.2.2.2.4 of ANSI/IEEE 802.3-1985 and its generation is described in section 7.2.4.6 of the same document." REFERENCE "ANSI/IEEE Std 802.3-1985 Carrier Sense Multiple Access with Collision Detection Access Method and Physical Layer Specifications" ::= { dot3StatsEntry 6 }
dot3StatsDeferredTransmissions OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "A count of frames for which the first transmission attempt on a particular interface is delayed because the medium is busy.
The count represented by an instance of this object does not include frames involved in collisions." REFERENCE "IEEE 802.3 Layer Management" ::= { dot3StatsEntry 7 }
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dot3StatsLateCollisions OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of times that a collision is detected on a particular interface later than 512 bit-times into the transmission of a packet.
Five hundred and twelve bit-times corresponds to 51.2 microseconds on a 10 Mbit/s system. A (late) collision included in a count represented by an instance of this object is also considered as a (generic) collision for purposes of other collision-related statistics." REFERENCE "IEEE 802.3 Layer Management" ::= { dot3StatsEntry 8 }
dot3StatsExcessiveCollisions OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "A count of frames for which transmission on a particular interface fails due to excessive collisions." REFERENCE "IEEE 802.3 Layer Management" ::= { dot3StatsEntry 9 }
dot3StatsInternalMacTransmitErrors OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "A count of frames for which transmission on a particular interface fails due to an internal MAC sublayer transmit error. A frame is only counted by an instance of this object if it is not counted by the corresponding instance of either the dot3StatsLateCollisions object, the dot3StatsExcessiveCollisions object, or the dot3StatsCarrierSenseErrors object.
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The precise meaning of the count represented by an instance of this object is implementation- specific. In particular, an instance of this object may represent a count of transmission errors on a particular interface that are not otherwise counted." REFERENCE "IEEE 802.3 Layer Management" ::= { dot3StatsEntry 10 }
dot3StatsCarrierSenseErrors OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "The number of times that the carrier sense condition was lost or never asserted when attempting to transmit a frame on a particular interface.
The count represented by an instance of this object is incremented at most once per transmission attempt, even if the carrier sense condition fluctuates during a transmission attempt." REFERENCE "IEEE 802.3 Layer Management" ::= { dot3StatsEntry 11 }
-- { dot3StatsEntry 12 } is not assigned
dot3StatsFrameTooLongs OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "A count of frames received on a particular interface that exceed the maximum permitted frame size.
The count represented by an instance of this object is incremented when the frameTooLong status is returned by the MAC service to the LLC (or other MAC user). Received frames for which multiple error conditions obtain are, according to the conventions of IEEE 802.3 Layer Management, counted exclusively according to the error status presented to the LLC."
dot3StatsInternalMacReceiveErrors OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "A count of frames for which reception on a particular interface fails due to an internal MAC sublayer receive error. A frame is only counted by an instance of this object if it is not counted by the corresponding instance of either the dot3StatsFrameTooLongs object, the dot3StatsAlignmentErrors object, or the dot3StatsFCSErrors object.
The precise meaning of the count represented by an instance of this object is implementation- specific. In particular, an instance of this object may represent a count of receive errors on a particular interface that are not otherwise counted." REFERENCE "IEEE 802.3 Layer Management" ::= { dot3StatsEntry 16 }
dot3StatsEtherChipSet OBJECT-TYPE SYNTAX OBJECT IDENTIFIER ACCESS read-only STATUS mandatory DESCRIPTION "This object contains an OBJECT IDENTIFIER which identifies the chipset used to realize the interface. Ethernet-like interfaces are typically built out of several different chips. The MIB implementor is presented with a decision of which chip to identify via this object. The implementor should identify the chip which is usually called the Medium Access Control chip. If no such chip is easily identifiable, the implementor should identify the chip
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which actually gathers the transmit and receive statistics and error indications. This would allow a manager station to correlate the statistics and the chip generating them, giving it the ability to take into account any known anomalies in the chip." ::= { dot3StatsEntry 17 }
-- the Ethernet-like Collision Statistics group
-- Implementation of this group is optional; it is appropriate -- for all systems which have the necessary metering
dot3CollTable OBJECT-TYPE SYNTAX SEQUENCE OF Dot3CollEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A collection of collision histograms for a particular set of interfaces." ::= { dot3 5 }
dot3CollEntry OBJECT-TYPE SYNTAX Dot3CollEntry ACCESS not-accessible STATUS mandatory DESCRIPTION "A cell in the histogram of per-frame collisions for a particular interface. An instance of this object represents the frequency of individual MAC frames for which the transmission (successful or otherwise) on a particular interface is accompanied by a particular number of media collisions." INDEX { ifIndex, dot3CollCount } ::= { dot3CollTable 1 }
SYNTAX INTEGER (1..16) ACCESS not-accessible STATUS mandatory DESCRIPTION "The number of per-frame media collisions for which a particular collision histogram cell represents the frequency on a particular interface." ::= { dot3CollEntry 2 }
dot3CollFrequencies OBJECT-TYPE SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION "A count of individual MAC frames for which the transmission (successful or otherwise) on a particular interface occurs after the frame has experienced exactly the number of collisions in the associated dot3CollCount object.
For example, a frame which is transmitted on interface 77 after experiencing exactly 4 collisions would be indicated by incrementing only dot3CollFrequencies.77.4. No other instance of dot3CollFrequencies would be incremented in this example." ::= { dot3CollEntry 3 }
-- 802.3 Tests
dot3Tests OBJECT IDENTIFIER ::= { dot3 6 }
dot3Errors OBJECT IDENTIFIER ::= { dot3 7 }
-- TDR Test
-- The Time-Domain Reflectometry (TDR) test is specific -- to ethernet-like interfaces with the exception of -- 10BaseT and 10BaseF. The TDR value may be useful -- in determining the approximate distance to a cable fault. -- It is advisable to repeat this test to check for a -- consistent resulting TDR value, to verify that there -- is a fault.
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dot3TestTdr OBJECT IDENTIFIER ::= { dot3Tests 1 }
-- A TDR test returns as its result the time interval, -- measured in 10 MHz ticks or 100 nsec units, between -- the start of TDR test transmission and the subsequent -- detection of a collision or deassertion of carrier. On -- successful completion of a TDR test, the result is -- stored as the value of the appropriate instance of the -- MIB object dot3TestTdrValue, and the OBJECT IDENTIFIER -- of that instanceis stored in the corresponding instance -- of ifExtnsTestCode (thereby indicating where the -- result has been stored).
-- Loopback Test
-- Another test is the full-duplex loopback test. -- This test configures the MAC chip and executes -- an internal loopback test of memory, data paths, -- and the MAC chip logic. This loopback test can -- only be executed if the interface is offline. -- Once the test has completed, the MAC chip should -- be reinitialized for network operation, but it -- should remain offline.
-- If an error occurs during a test, the object -- ifTestResult (defined in RFC1573) will be set -- to failed(7). The following two OBJECT -- IDENTIFIERs may be used to provided more -- information as values for ifTestCode.
-- couldn't initialize MAC chip for test dot3ErrorInitError OBJECT IDENTIFIER ::= { dot3Errors 1 }
-- expected data not received (or not -- received correctly) in loopback test dot3ErrorLoopbackError OBJECT IDENTIFIER ::= { dot3Errors 2 }
-- RFC1573 does away with the interface chipset object. -- The following OBJECT IDENTIFIER definitions are -- retained for purposes of backwards compatibility -- with pre-RFC1573 systems. -- 802.3 Hardware Chipsets
-- The object ifExtnsChipSet is provided in RFC1229 to -- identify the MAC hardware used to communcate on an
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-- interface. The following hardware chipsets are -- provided for 802.3:
-- For those chipsets not represented above, OBJECT IDENTIFIER -- assignment is required in other documentation, e.g., assignment -- within that part of the registration tree delegated to -- individual enterprises (see RFC1155).
END
5. Acknowledgements
This document was produced by the Ethernet MIB Working Group.
This document is based on the Proposed Standard Ethernet MIB, RFC 1284 [14], of which Jihn Cook of Chipcom was the editor. The Ethernet MIB Working Group gathered implementation experience of the variables specified in RFC 1284 and used that information to develop this revised MIB.
RFC 1284, in turn, is based on a document written by Frank Kastenholz
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of Interlan entitled IEEE 802.3 Layer Management Draft M compatible MIB for TCP/IP Networks [10]. This document has been modestly reworked, initially by the SNMP Working Group, and then by the Transmission Working Group, to reflect the current conventions for defining objects for MIB interfaces. James Davin, of the MIT Laboratory for Computer Science, and Keith McCloghrie of Hughes LAN Systems, contributed to later drafts of this memo. Marshall Rose of Performance Systems International, Inc. converted the document into its current concise format. Anil Rijsinghani of DEC contributed text that more adequately describes the TDR test. Thanks to Frank Kastenholz of Interlan and Louis Steinberg of IBM for their experimentation.
6. References
[1] Cerf, V., "IAB Recommendations for the Development of Internet Network Management Standards", RFC 1052, NRI, April 1988.
[2] Cerf, V., "Report of the Second Ad Hoc Network Management Review Group", RFC 1109, NRI, August 1989.
[3] Rose M., and K. McCloghrie, "Structure and Identification of Management Information for TCP/IP-based internets", STD 16, RFC 1155, Performance Systems International, Hughes LAN Systems, May 1990.
[4] McCloghrie K., and M. Rose, "Management Information Base for Network Management of TCP/IP-based internets", RFC 1156, Hughes LAN Systems, Performance Systems International, May 1990.
[5] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple Network Management Protocol", STD 15, RFC 1157, SNMP Research, Performance Systems International, Performance Systems International, MIT Laboratory for Computer Science, May 1990.
[6] McCloghrie K., and M. Rose, Editors, "Management Information Base for Network Management of TCP/IP-based internets", STD 17, RFC 1213, Performance Systems International, March 1991.
[7] Information processing systems - Open Systems Interconnection - Specification of Abstract Syntax Notation One (ASN.1), International Organization for Standardization, International Standard 8824, December 1987.
[8] Information processing systems - Open Systems Interconnection - Specification of Basic Encoding Rules for Abstract Notation One (ASN.1), International Organization for Standardization, International Standard 8825, December 1987.
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[9] IEEE, "IEEE 802.3 Layer Management", November 1988.
[10] Kastenholz, F., "IEEE 802.3 Layer Management Draft compatible MIB for TCP/IP Networks", electronic mail message to mib- wg@nnsc.nsf.net, 9 June 1989.
[11] McCloghrie, K., Editor, "Extensions to the Generic-Interface MIB", RFC 1229, Hughes LAN Systems, Inc., May 1991.
[12] IEEE, "Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access Method and Physical Layer Specifications", ANSI/IEEE Std 802.3-1985.
[13] Rose, M., and K. McCloghrie, Editors, "Concise MIB Definitions", RFC 1212, Performance Systems International, Hughes LAN Systems, March 1991.
[14] Cook, J., Editor, "Definitions of Managed Objects for Ethernet- Like Interface Types", RFC 1284, Chipcom Corporation, December 1991.
[15] Kastenholz, F., "Definitions of Managed Objects for the Ethernet-like Interface Types", RFC 1398, FTP Software, Inc., January 1993.
[16] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Structure of Management Information for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1442, SNMP Research, Inc., Hughes LAN Systems, Dover Beach Consulting, Inc., Carnegie Mellon University, April 1993.
[17] Galvin, J., and K. McCloghrie, "Administrative Model for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1445, Trusted Information Systems, Hughes LAN Systems, April 1993.
[18] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Protocol Operations for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1448, SNMP Research, Inc., Hughes LAN Systems, Dover Beach Consulting, Inc., Carnegie Mellon University, April 1993.
[19] McCloghrie, K., and F. Kastenholz, "Evolution of the Interfaces Group of MIB-II", RFC 1573, Hughes LAN Systems, FTP Software, January 1994.
[20] Kastenholz, F., "Definitions of Managed Objects for the Ethernet-like Interface Types", STD 50, RFC 1623, FTP Software, Inc., May 1994.
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7. Security Considerations
Security issues are not discussed in this memo.
8. Author's Address
Frank Kastenholz FTP Software, Inc. 2 High Street North Andover, Mass, USA 01845
