Network Working Group A. Bierman

Network Working Group A. Bierman
Request for Comments: 3395 C. Bucci
Updates: 2895 Cisco Systems, Inc.
Category: Standards Track R. Dietz
Hifn, Inc.
A. Warth
September 2002

Remote Network Monitoring MIB Protocol Identifier Reference Extensions

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.

Copyright Notice

Copyright (C) The Internet Society (2002). All Rights Reserved.

Abstract

This memo defines extensions to the Protocol Identifier Reference
document for the identification of application verb information. It
updates the Protocol Identifier Reference document but does not
obsolete any portion of that document. In particular, it describes
the algorithms required to identify protocol operations (verbs)
within the protocol encapsulations managed with MIBs such as the
Remote Network Monitoring MIB Version 2, RFC 2021.

Table of Contents

1. The SNMP Network Management Framework ..........................2
2. Overview .......................................................3
2.1 Protocol Identifier Framework .................................3
2.2 Protocol Identifier Extensions for Application Verbs ..........4
2.3 Terms .........................................................4
2.4 Relationship to the RMON-2 MIB ................................5
2.5 Relationship to the RMON MIB Protocol Identifier Reference.....5
3. Definitions ....................................................5
3.1 Verb Identifier Macro Format ..................................5
3.1.1 Lexical Conventions .........................................6
3.1.2 Extended Grammar for the PI Language ........................6
3.1.3 Mapping of the Parent Protocol Name .........................7
3.1.4 Mapping of the DESCRIPTION Clause ...........................7

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3.1.5 Mapping of the REFERENCE Clause .............................7
3.1.6 Mapping of the Verb List Clause .............................7
3.1.6.1 Mapping of the Verb Name Field ............................8
3.1.6.2 Mapping of the Verb Enum Field ............................8
3.2 Protocol Directory Requirements ...............................8
3.2.1 Mapping of the Verb Layer Numbering Space ...................8
3.2.2 Mapping of the ProtocolDirID object .........................9
3.2.3 Mapping of the ProtocolDirParameters object .................9
3.2.4 Mapping of the ProtocolDirLocalIndex object ................10
3.2.5 Mapping of the protocolDirDescr object .....................10
3.2.6 Mapping of the protocolDirType object ......................10
3.2.7 Mapping of the protocolDirAddressMapConfig object ..........10
3.2.8 Mapping of the protocolDirHostConfig object ................10
3.2.9 Mapping of the protocolDirMatrixConfig object ..............10
3.2.10 Mapping of the protocolDirOwner object ....................11
3.2.11 Mapping of the protocolDirStatus object ...................11
4. Implementation Considerations .................................11
4.1 Stateful Protocol Decoding ...................................11
4.2 Packet Capture ...............................................11
4.3 RMON-2 MIB Collections .......................................12
5. Intellectual Property .........................................12
6. Acknowledgements ..............................................13
7. Normative References ..........................................13
8. Informative References ........................................14
9. IANA Considerations ...........................................15
10. Security Considerations ......................................15
Appendix A: Usage Examples .......................................16
A.1 FTP Example ..................................................16
A.2 POP3 Example .................................................17
A.3 SNMP Example .................................................18
A.4 HTTP Example .................................................18
A.5 SMTP Example .................................................19
Authors' Addresses ...............................................20
Full Copyright Statement..........................................21

1. The SNMP Network Management Framework

The SNMP Management Framework presently consists of five major
components:

o An overall architecture, described in RFC 2571 [RFC2571].

o Mechanisms for describing and naming objects and events for the
purpose of management. The first version of this Structure of
Management Information (SMI) is called SMIv1 and is described
in STD 16, RFC 1155 [RFC1155], STD 16, RFC 1212 [RFC1212] and

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RFC 1215 [RFC1215]. The second version, called SMIv2, is
described in STD 58, RFC 2578 [RFC2578], RFC 2579 [RFC2579] and
RFC 2580 [RFC2580].

o Message protocols for transferring management information. The
first version of the SNMP message protocol is called SNMPv1 and
is described in STD 15, RFC 1157 [RFC1157]. A second version
of the SNMP message protocol, which is not an Internet
standards track protocol, is called SNMPv2c and is described in
RFC 1901 [RFC1901] and RFC 1906 [RFC1906]. The third version
of the message protocol is called SNMPv3 and is described in
RFC 1906 [RFC1906], RFC 2572 [RFC2572] and RFC 2574 [RFC2574].

o Protocol operations for accessing management information. The
first set of protocol operations and associated PDU formats is
described in STD 15, RFC 1157 [RFC1157]. A second set of
protocol operations and associated PDU formats is described in
RFC 1905 [RFC1905].

o A set of fundamental applications is described in RFC 2573
[RFC2573]. The view-based access control mechanism is
described in RFC 2575 [RFC2575].

A more detailed introduction to the current SNMP Management Framework
can be found in RFC 2570 [RFC2570].

Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. Objects in the MIB are
defined using the mechanisms defined in the SMI.

This memo does not specify a MIB module.

2. Overview

There is a need for a standardized way of identifying the protocol
operations defined for particular application protocols. Different
protocol operations can have very different performance
characteristics, and it is desirable to collect certain metrics at
this level of granularity. This memo defines extensions to the
existing protocol identifier structure [RFC2895] and is intended to
update, not obsolete, the existing protocol identifier encoding
rules.

2.1 Protocol Identifier Framework

The RMON Protocol Identifier (PI) structure [RFC2895] allows for a
variable number of layer identifiers. Each layer contributes 4
octets to the protocolDirID OCTET STRING and one octet to the

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protocolDirParameters OCTET STRING. These two MIB objects comprise
the index in the protocolDirTable [RFC2021] and represent a globally
unique identifier for a particular protocol encapsulation (or set of
encapsulations if the wild-card base layer is used).

2.2 Protocol Identifier Extensions for Application Verbs

The existing RMON protocol identifier architecture requires that an
application verb be represented by one additional protocol layer,
appended to the protocol identifier for the parent application.
Since some application verbs are defined as strings which can exceed
4 octets in length, an integer mapping must be provided for each
string. This memo specifies how the verb layer is structured, as
well as a verb identifier macro syntax for specification of verb name
to integer mappings.

2.3 Terms

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].

This document uses some terms defined in the RMON Protocol Identifier
Reference document [RFC2895] and some new terms that need
introduction here.

Application Verb
Also called simply 'verb'. Refers to one of potentially many
protocol operations that are defined by a particular application
protocol.

Note that an application verb is not equivalent to an application
protocol sub-command or opcode within a packet containing a PDU
for the application. An application verb is a transaction type
and may involve several PDU types within the application protocol
(e.g., SNMP Get-PDU and Response-PDU). In some applications, a
verb may encompass protocol operations pertaining to more than one
protocol entry in the protocol directory (e.g., ftp and ftp-data).

Connect Verb
The special application verb associated with connection or session
setup and tear-down traffic, and not attributed to any other verb
for the application. This verb is assigned the enumeration value
of zero, and the verb 'connect(0)' is implicitly defined for all
application protocols.

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Parent Application
One of potentially many protocol encapsulations which identifies a
particular application protocol. This term refers generically to
any or all such encapsulations for a given set of application
verbs.

Verb Layer
The portion of the protocol identifier octet string which
identifies the application verb.

Verb Set
The group of verbs enumerated for a particular application
protocol. The list of verb strings within a particular verb-
identifier macro invocation is also called the verb set for that
verb identifier.

2.4 Relationship to the RMON-2 MIB

The RMON-2 MIB [RFC2021] contains the protocolDirTable MIB objects
used to identify all protocol encapsulations that can be monitored by
a particular RMON agent.

This memo describes how these MIB objects are mapped by an
implementation for entries which identify application verbs. This
document does not define any new MIB objects to identify application
verbs. The applicability of the definitions in this document is not
limited to the RMON-2 MIB. Other specifications which utilize the
RMON-2 protocolDirTable and/or the protocol identifier macros which
it represents can also utilize the application verb macro definitions
contained in this document.

2.5 Relationship to the RMON MIB Protocol Identifier Reference

The RMON MIB Protocol Identifier Reference [RFC2895] defines the RMON
Protocol Identifier Macro Specification Language as well as the
encoding rules for the ProtocolDirID and protocolDirParameters OCTET
STRINGs. This memo defines extensions to the Protocol Identifier
Reference for the identification of application verb information. It
does not obsolete any portion of the Protocol Identifier Reference
document.

3. Definitions

3.1 Verb Identifier Macro Format

The following example is meant to introduce the verb-identifier
macro. This macro-like construct is used to represent protocol verbs
for a specific parent application.

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3.1.1 Lexical Conventions

The following keyword is added to the PI language:

VERB-IDENTIFIER

3.1.2 Extended Grammar for the PI Language

The following is the extended BNF notation for the grammar with
starting symbol <piFile>. It is for representing verb identifier
macros. Note that only the term <piFile> is actually modified from
the definition in [RFC2895]. The <piDefinition> syntax is not
reproduced here, since this memo is intended to extend that
definition, not replace it.

-- a file containing one or more
-- Protocol Identifier (PI) definitions
<piFile> = [ <piDefinition> | <piVerbDefinition> ]...

-- a PI definition
<piVerbDefinition> =
[<wspace>] <parentProtoName> <wspace> "VERB-IDENTIFIER"
<wspace> "DESCRIPTION" <wspace> string
[ <wspace> "REFERENCE" <wspace> string ]
[<wspace>] "::=" [<wspace>]
"{" [<wspace>] <verbList> [<wspace>] "}" [<wspace>]

-- a list of verb identifier string
<verbList> = <verbId> [ [<wspace>] "," [<wspace>] <verbId> ]...

-- a verb identifier string
<verbId> = <verbName> [<wspace>] "(" [<wspace>]
<verbEnum> [<wspace>] ")" [<wspace>]

-- a protocol name
<parentProtoName> = <protoName>

-- a verb name
<verbName> = <lcname>

-- a verb enumeration
<verbEnum> = <posNum>

-- a positive integer
<posNum> = any integer value greater than zero and
less than 16,777,216

-- <piDefinition> syntax is defined in [RFC2895]

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-- <protoName> syntax is defined in [RFC2895]
-- <wspace> syntax is defined in [RFC2895]
-- <lcname> syntax is defined in [RFC2895]

3.1.3 Mapping of the Parent Protocol Name

The "parentProtoName" value, called the "parent protocol name",
SHOULD be an ASCII string consisting of 1 to 64 characters. (These
names are intended to appear in IETF documentation, so the use of
UTF-8 is not appropriate.) The encoding rules are exactly as
specified in section 6.2.4 of [RFC2895] for the mapping of the
protocol name field. The value for <parentProtoName> (which is
called the "parent protocol name") MUST be the value of a protocol
identifier defined as specified for <protoName> in section 3.2.4 of
[RFC2895]. The value of <parentProtoName> MUST specify a <protoName>
defined in the <piFile>.

A protocol identifier macro SHOULD exist in the <piFile> for at least
one encapsulation of the parent application protocol if any verb
identifier macros referencing that parent application are present in
the <piFile>.

3.1.4 Mapping of the DESCRIPTION Clause

The DESCRIPTION clause provides a textual description of the protocol
verb set identified by this macro. It SHOULD NOT contain details
about items covered by the REFERENCE clause. The DESCRIPTION clause
MUST be present in all verb-identifier macro declarations.

3.1.5 Mapping of the REFERENCE Clause

If a publicly available reference document exists for this set of
application protocol verbs, it SHOULD be listed here. Typically this
will be a URL, otherwise it will be the name and address of the
controlling body.

The REFERENCE clause is optional but SHOULD be present if an
authoritative reference exists which specifies the application
protocol verbs defined in the <verbList> section of this macro.

3.1.6 Mapping of the Verb List Clause

The verb list clause MUST be present. It is used to identify a list
of application verb names and associate a numeric constant with each
verb name. At least one verb MUST be specified and a maximum of
16,777,215 (2^^24 - 1) verbs MAY be specified. This enumerated list
SHOULD be densely numbered (i.e., valued from '1' to 'N', where 'N'
is the total number of verbs defined in the macro).

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3.1.6.1 Mapping of the Verb Name Field

The <verbName> field is case-sensitive and SHOULD be set to the most
appropriate string name for each application verb. If such a
descriptive string is defined in an authoritative document then that
string SHOULD be used. If no such string exists then an appropriate
but arbitrary string should be selected for this value.

Verb names MUST be unique for a particular parent application. Note
that the special 'connect(0)' verb is implicitly defined for each
application protocol. It is possible for an explicit definition of
this verb (e.g., 'connect(8)' for http) to exist for a protocol, as
well as the implicit 'connect(0)' verb.

3.1.6.2 Mapping of the Verb Enum Field

The <verbEnum> field MUST be unique for all verbs associated with a
particular parent application. This field SHOULD contain a value
between '1' and '16,777,215' inclusive.

3.2 Protocol Directory Requirements

This section defines how the protocolDirTable should be populated for
any application verb identified with a verb-identifier macro.

An agent MUST implement all applicable protocolDirTable MIB objects
on behalf of each supported application verb.

3.2.1 Mapping of the Verb Layer Numbering Space

The verb layer consists of the 4 octets within the protocolDirID
INDEX field which identify a particular application verb.

Figure 1
Verb Layer Format
-----------------

protocolDirID string fragment
---+--------+--------+--------+--------+
| resrvd | |
.. | set to | verb enumeration value |
| zero | (a) (b) (c) |
---+--------+--------+--------+--------+ octet
| 1 | 3 | count

The first octet is reserved for future use and MUST be set to zero.

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The next three octets identify the <verbEnum> field used to enumerate
the particular application verb represented by the <verbName> field.
This field is a 24-bit unsigned integer, encoded in network byte
order.

The value zero is reserved to identify the special 'connect(0)' verb.
This verb enumeration value (i.e., '0' part of 'connect(0)') MUST NOT
be redefined in a verb identifier macro verb list. Note that the
verb name 'connect' is not reserved and MAY be redefined in a verb
list.

3.2.2 Mapping of the ProtocolDirID object

The protocolDirID OCTET STRING value for a particular application
verb is represented by the protocolDirID value for the parent
application, appended with the verb's layer identifier value.

Figure 2
ProtocolDirID Format for Verbs
------------------------------

protocolDirID string
+--------+--------+--------+--------+
| parent | verb |
| protocolDirID | layer |
| string | value |
+--------+--------+--------+--------+ octet
| length of parent ID | 4 | count

The protocolDirID object is encoded as the protocolDirID value of the
parent application, followed by four additional octets representing
the verb layer. The verb layer value is encoded as [0.a.b.c] where
'a' is the high order byte, 'b' is the middle order byte, and 'c' is
the low order byte of the <verbEnum> field for the specific
application verb value. A valid PI verb enumeration will be encoded
in the range "0.0.0.0" to "0.255.255.255", where the special value
"0.0.0.0" is reserved for the implicitly defined 'connect(0)' verb.

3.2.3 Mapping of the ProtocolDirParameters object

The protocolDirParameters OCTET STRING value for a particular
application verb is represented by the protocolDirParameters value
for the parent application, appended with one octet containing the
value zero. Although not actually used, this field is included to
conform to the encoding rules defined in the Protocol Identifiers
Reference [RFC2895].

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3.2.4 Mapping of the ProtocolDirLocalIndex object

The agent MUST assign an appropriate protocolDirLocalIndex value for
each application verb according to the encoding rules defined for
this object in [RFC2021] and [RFC2895].

3.2.5 Mapping of the protocolDirDescr object

The agent MUST convey the <verbName> value for a particular
application verb in the protocolDirDescr object. This object SHOULD
be encoded as the protocolDirDescr value for the parent application
appended with a 'dot' character, followed by the exact text contained
in the <verbName> field.

3.2.6 Mapping of the protocolDirType object

The agent MUST set the protocolDirType object for each application
verb to the value representing the empty bit set ( {} ).

3.2.7 Mapping of the protocolDirAddressMapConfig object

The agent MUST set the protocolDirAddressMapConfig object for each
application verb to the value 'notSupported(1)'.

3.2.8 Mapping of the protocolDirHostConfig object

The agent MUST set the protocolDirHostConfig object for each
application verb present in the protocol directory according to the
monitoring capabilities for each verb. The agent MAY set this object
to the same value as configured in the parent application
protocolDirHostConfig object. The agent MAY choose to transition
this object from the value 'supportedOn(2)' to 'supportedOff(3)' if
the parent application protocolDirHostConfig object first transitions
from 'supportedOn(2)' to 'supportedOff(3)'.

3.2.9 Mapping of the protocolDirMatrixConfig object

The agent MUST set the protocolDirMatrixConfig object for each
application verb according to the monitoring capabilities for each
verb. The agent MAY set this object to the same value as configured
in the parent application protocolDirMatrixConfig object. The agent
MAY choose to transition this object from the value 'supportedOn(2)'
to 'supportedOff(3)' if the parent application
protocolDirMatrixConfig object first transitions from
'supportedOn(2)' to 'supportedOff(3)'.

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3.2.10 Mapping of the protocolDirOwner object

This object is encoded exactly the same for application verbs as for
other protocolDirTable entries, according to the rules specified in
the RMON-2 MIB [RFC2021].

3.2.11 Mapping of the protocolDirStatus object

This object is encoded exactly the same for application verbs as for
other protocolDirTable entries, according to the rules specified in
RMON-2 MIB [RFC2021].

4. Implementation Considerations

This section discusses the implementation implications for agents
which support verbs in the protocol directory and the RMON
collections which utilize the protocol directory.

4.1 Stateful Protocol Decoding

Implementations of the RMON-2 MIB for application layer and network
layer protocols typically require little if any state to be
maintained by the probe. The probe can generally decide whether to
count a packet and its octets on the packet's own merits, without
referencing or updating any state information.

Implementations of the RMON-2 MIB at the verb layer will, for many
protocols, need to maintain state information in order to correctly
classify a packet as "belonging" to one verb or another. The
examples below illustrate this point.

For SNMP over UDP, a Response-PDU for an SNMP Get-PDU can't be
distinguished from a Response-PDU for a Getnext-PDU. A probe would
need to maintain state information in order to correlate a Response-
PDU from B to A with a previous request from A to B.

For application protocols carried over a stream-based transport such
as TCP, the information required to identify an application verb can
span several packets. A probe would need to follow the transport-
layer flow in order to correctly parse the application-layer data.

4.2 Packet Capture

For packet capture based on verb-layer protocol directory filtering,
the decision to include a packet in the capture buffer may need to be
deferred until the packet can be conclusively attributed to a

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particular verb. A probe may need to pre-buffer packets while
deciding to include or exclude them from capture based on other
packets that have not yet arrived.

4.3 RMON-2 MIB Collections

Data collections such as the protocol distribution or Application
Layer Host Table (alHostTable) require that each packet is counted
only once, i.e., a given packet is fully classified as a single
protocol encapsulation which resolves to a single leaf entry in the
protocol directory. Also, octet counters related to protocol
classification are incremented by the entire size of packet, not just
the octets associated with a particular encapsulation layer.

It is possible that particular application protocols will allow
multiple types of verbs to be present in a single packet. In this
case, the agent MUST choose one verb type, and therefore one protocol
directory entry, in order to properly count such a packet.

It is an implementation-specific matter as to which verb type an
agent selects to identify a packet in the event more than one verb
type is present in that packet. Some possible choices include:

- the first verb type encountered in the packet

- the verb type with the most instances in the packet

- the verb type using the largest number of octets in the packet

- the most 'interesting' verb type in the packet (based on
knowledge of that application protocol).

5. Intellectual Property

The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances of
licenses to be made available, or the result of an attempt made to
obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat.

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The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.

6. Acknowledgements

This memo is a product of the RMONMIB WG.

7. Normative References

[RFC1905] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M.
and S. Waldbusser, "Protocol Operations for Version 2 of
the Simple Network Management Protocol (SNMPv2)", RFC 1905,
January 1996.

[RFC1906] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M.
and S. Waldbusser, "Transport Mappings for Version 2 of
the Simple Network Management Protocol (SNMPv2)", RFC 1906,
January 1996.

[RFC2021] Waldbusser, S., "Remote Network Monitoring MIB (RMON-2)",
RFC 2021, January 1997.

[RFC2026] Bradner, S., "The Internet Standards Process -- Revision
3", BCP 9, RFC 2026, October 1996.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC2571] Harrington, D., Presuhn, R. and B. Wijnen, "An Architecture
for Describing SNMP Management Frameworks", RFC 2571, April
1999.

[RFC2572] Case, J., Harrington D., Presuhn R. and B. Wijnen, "Message
Processing and Dispatching for the Simple Network
Management Protocol (SNMP)", RFC 2572, April 1999.

[RFC2573] Levi, D., Meyer, P. and B. Stewart, "SNMPv3 Applications",
RFC 2573, April 1999.

[RFC2574] Blumenthal, U. and B. Wijnen, "User-based Security Model
(USM) for version 3 of the Simple Network Management
Protocol (SNMPv3)", RFC 2574, April 1999.

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[RFC2575] Wijnen, B., Presuhn, R. and K. McCloghrie, "View-based
Access Control Model (VACM) for the Simple Network
Management Protocol (SNMP)", RFC 2575, April 1999.

[RFC2578] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,
Rose, M. and S. Waldbusser, "Structure of Management
Information Version 2 (SMIv2)", STD 58, RFC 2578, April
1999.

[RFC2579] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,
Rose, M. and S. Waldbusser, "Textual Conventions for
SMIv2", STD 58, RFC 2579, April 1999.

[RFC2580] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,
Rose, M. and S. Waldbusser, "Conformance Statements for
SMIv2", STD 58, RFC 2580, April 1999.

[RFC2895] Bierman, A., Bucci, C. and R. Iddon, "Remote Network
Monitoring MIB Protocol Identifiers", RFC 2895, August
2000.

8. Informative References

[RFC1155] Rose, M. and K. McCloghrie, "Structure and Identification
of Management Information for TCP/IP-based Internets", STD
16, RFC 1155, May 1990.

[RFC1157] Case, J., Fedor, M., Schoffstall, M. and J. Davin, "Simple
Network Management Protocol", STD 15, RFC 1157, May 1990.

[RFC1212] Rose, M. and K. McCloghrie, "Concise MIB Definitions", STD
16, RFC 1212, March 1991.

[RFC1215] Rose, M., "A Convention for Defining Traps for use with the
SNMP", RFC 1215, March 1991.

[RFC1901] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M.
and S. Waldbusser, "Introduction to Community-based
SNMPv2", RFC 1901, January 1996.

[RFC2570] Case, J., Mundy, R., Partain, D. and B. Stewart,
"Introduction to Version 3 of the Internet-standard Network
Management Framework", RFC 2570, April 1999.

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9. IANA Considerations

At this time there are no application protocol verbs defined that
require IANA registration, similar to the 'ianaAssigned' protocol
identifiers found in RFC 2895. It is remotely possible that a future
version of this document will contain application verb definitions
which require assignment in the 'ianaAssigned' protocol identifier
subtree.

10. Security Considerations

This memo defines the structure of a portion of the Remote Monitoring
MIB framework, but does not define any MIB objects or protocol
operations. Instead, it defines algorithms for representing
application protocol verbs in RMON Protocol Identifiers. It does not
introduce any new security risks into a managed system.

However, if an MIB collection is designed which utilizes this type of
Protocol Identifier, then such a collection may expose which verbs in
an application protocol are used in a network. Inclusion of this
additional information may require more consideration for protection.
MIB writers should address such considerations.

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Appendix A: Usage Examples

The following examples are listed to demonstrate how RMON verb
identifiers are declared.

A.1 FTP Example

This example defines verb enumeration values for the File Transfer
Protocol as defined in RFC 959 and updated by RFC 2228 and RFC 2640.
Note that verb name strings specified in the <verbName> field are not
limited to 4 characters in length. In the FTP protocol, all the
command names are 4 characters in length and the verb name string
should match the official command name as closely as possible.

ftp VERB-IDENTIFIER
DESCRIPTION
"The set of verbs for FTP is derived from the list
of commands defined for the File Transfer Protocol,
which are identified by case-insensitive strings.
The commands are simply listed in the order found
in the FTP documentation."
REFERENCE
"File Transfer Protocol, RFC 959, Section 4.1;
FTP Security Extensions, RFC 2228, Section 3;
Internationalization of the File Transfer Protocol,
RFC 2640, Section 4.1."
::= {
user(1), -- USER NAME
pass(2), -- PASSWORD
acct(3), -- ACCOUNT
cwd(4), -- CHANGE WORKING DIRECTORY
cdup(5), -- CHANGE TO PARENT DIRECTORY
smnt(6), -- STRUCTURE MOUNT
rein(7), -- REINITIALIZE
quit(8), -- LOGOUT
port(9), -- DATA PORT
pasv(10), -- PASSIVE
type(11), -- REPRESENTATION TYPE
stru(12), -- FILE STRUCTURE
mode(13), -- TRANSFER MODE
retr(14), -- RETRIEVE
stor(15), -- STORE
stou(16), -- STORE UNIQUE
appe(17), -- APPEND (with create)
allo(18), -- ALLOCATE
rest(19), -- RESTART
rnfr(20), -- RENAME FROM
rnto(21), -- RENAME TO

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RFC 3395 RMON Verb Identifiers September 2002

abor(22), -- ABORT
dele(23), -- DELETE
rmd(24), -- REMOVE DIRECTORY
mkd(25), -- MAKE DIRECTORY
pwd(26), -- PRINT WORKING DIRECTORY
list(27), -- LIST
nlst(28), -- NAME LIST
site(29), -- SITE PARAMETERS
syst(30), -- SYSTEM
stat(31), -- STATUS
help(32), -- HELP
noop(33), -- NOOP
auth(34), -- AUTHENTICATION/SECURITY MECHANISM
adat(35), -- AUTHENTICATION/SECURITY DATA
pbsz(36), -- PROTECTION BUFFER SIZE
prot(37), -- DATA CHANNEL PROTECTION LEVEL
ccc(38), -- CLEAR COMMAND CHANNEL
mic(39), -- INTEGRITY PROTECTED COMMAND
conf(40), -- CONFIDENTIALITY PROTECTED COMMAND
enc(41), -- PRIVACY PROTECTED COMMAND
lang(42) -- LANGUAGE
}

A.2 POP3 Example

This example defines verb enumeration values for the Post Office
Protocol, Version 3, as defined in RFC 1939 and updated by RFC 2449.

pop3 VERB-IDENTIFIER
DESCRIPTION
"The set of verbs for POP3 is derived from the list
of commands defined for the Post Office Protocol,
which are identified by case-insensitive strings.
The commands are simply listed in the order found
in the POP3 command summary."
REFERENCE
"Post Office Protocol, Version 3, RFC 1939, Section 9;
POP3 Extension Mechanism, RFC 2449, Section 5."
::= {
user(1),
pass(2),
quit(3),
stat(4),
list(5),
retr(6),
dele(7),
noop(8),
rset(9),

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RFC 3395 RMON Verb Identifiers September 2002

apop(10),
top(11),
uidl(12),
capa(13)
}

A.3 SNMP Example

This example defines verb enumeration values for the Simple Network
Management Protocol, as defined in RFC 1905.

snmp VERB-IDENTIFIER
DESCRIPTION
"The set of verbs for SNMP is derived from the list
of PDU transaction types in the Protocol Operations
document for SNMPv2. Note that the 'Response'
and 'Report' PDUs are not considered verbs, but are
classified as belonging to the transaction type
associated with the request PDU."
REFERENCE
"Protocol Operations for Version 2 of the
Simple Network Management Protocol (SNMPv2),
RFC 1905, Section 3."
::= {
get(1),
get-next(2),
get-bulk(3),
set(4),
inform-request(5),
trap(6)
}

A.4 HTTP Example

This example defines verb enumeration values for the Hypertext
Transfer Protocol, version 1.1, as defined in RFC 2616.

http VERB-IDENTIFIER
DESCRIPTION
"The set of verbs for HTTP is derived from the list
of methods defined for the Hypertext Transfer Protocol,
which are identified by case-sensitive strings.
The commands are simply listed in the order found
in the HTTP/1.1 documentation. Methods commonly used
in HTTP/1.0 are a proper subset of those used in HTTP/1.1.
Both versions of the protocol are in current use."
REFERENCE
"Hypertext Transfer Protocol -- HTTP/1.1, RFC 2616,

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RFC 3395 RMON Verb Identifiers September 2002

Section 9; Hypertext Transfer Protocol -- HTTP/1.0, RFC
1945, Section 8."
::= {
options(1),
get(2),
head(3),
post(4),
put(5),
delete(6),
trace(7),
connect(8) -- reserved for future use by HTTP/1.1
}

A.5 SMTP Example

This example defines verb enumeration values for the Simple Mail
Transfer Protocol as defined in RFC 2821.

smtp VERB-IDENTIFIER
DESCRIPTION
"The set of verbs for SMTP is derived from the set of commands
defined for the protocol. These commands are identified
by case-insensitive strings. Commands are listed in the
order found in RFC 2821. The special "xcmd" verb is defined
here as a catch-all for private-use commands, which must
start with the letter 'X'."
REFERENCE
"Simple Mail Transfer Protocol -- RFC 2821, sections 4.1.1
and 4.1.5."
::= {
ehlo(1), -- Extended HELLO (4.1.1.1)
helo(2), -- HELLO (4.1.1.1)
mail(3), -- MAIL (4.1.1.2)
rcpt(4), -- RECIPIENT (4.1.1.3)
data(5), -- DATA (4.1.1.4)
rset(6), -- RESET (4.1.1.5)
vrfy(7), -- VERIFY (4.1.1.6)
expn(8), -- EXPAND (4.1.1.7)
help(9), -- HELP (4.1.1.8)
noop(10), -- NOOP (4.1.1.9)
quit(11), -- QUIT (4.1.1.10)
xcmd(12) -- Catch-all for private-use "X" commands (4.1.5)
}

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RFC 3395 RMON Verb Identifiers September 2002

Authors' Addresses

Andy Bierman
Cisco Systems, Inc.
170 West Tasman Dr
San Jose, CA USA 95134

Phone: +1 408-527-3711
EMail: [email protected]

Chris Bucci
Cisco Systems, Inc.
170 West Tasman Dr
San Jose, CA USA 95134

Phone: +1 408-527-5337
EMail: [email protected]

Russell Dietz
Hifn, Inc.
750 University Ave
Los Gatos, CA, USA 95032-7695

Phone: +1 408-399-3623
EMail: [email protected]

Albin Warth

EMail: [email protected]

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RFC 3395 RMON Verb Identifiers September 2002

Full Copyright Statement

Copyright (C) The Internet Society (2002). All Rights Reserved.

This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.

The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.

This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

Funding for the RFC Editor function is currently provided by the
Internet Society.

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