RFC2233 ], is defined as the description of a network interface. To identify the description of device-X's first network interface, four pieces of information are needed: the snmpEngineID of the SNMP
RFC2233], is defined as
the description of a network interface. To identify the description
of device-X's first network interface, four pieces of information are
needed: the snmpEngineID of the SNMP entity which provides access to
the management information at device-X, the contextName (device-X),
the managed object type (ifDescr), and the instance ("1").
Each context has (at least) one unique identification within the
management domain. The same item of management information can exist
in multiple contexts. An item of management information may have
multiple unique identifications. This occurs when an item of
management information exists in multiple contexts, and this also
occurs when a context has multiple unique identifications.
The combination of a contextEngineID and a contextName unambiguously
identifies a context within an administrative domain; note that there
may be multiple unique combinations of contextEngineID and
contextName that unambiguously identify the same context.
3.3.2. contextEngineID
Within an administrative domain, a contextEngineID uniquely
identifies an SNMP entity that may realize an instance of a context
with a particular contextName.
3.3.3. contextName
A contextName is used to name a context. Each contextName MUST be
unique within an SNMP entity.
3.3.4. scopedPDU
A scopedPDU is a block of data containing a contextEngineID, a
contextName, and a PDU.
The PDU is an SNMP Protocol Data Unit containing information named in
the context which is unambiguously identified within an
administrative domain by the combination of the contextEngineID and
the contextName. See, for example,
RFC1905 for more information about
SNMP PDUs.
3.4. Other Constructs
3.4.1. maxSizeResponseScopedPDU
The maxSizeResponseScopedPDU is the maximum size of a scopedPDU that
a PDU's sender would be willing to accept. Note that the size of a
scopedPDU does not include the size of the SNMP message header.
3.4.2. Local Configuration Datastore
The subsystems, models, and applications within an SNMP entity may
need to retain their own sets of configuration information.
Portions of the configuration information may be accessible as
managed objects.
The collection of these sets of information is referred to as an
entity's Local Configuration Datastore (LCD).
3.4.3. securityLevel
This architecture recognizes three levels of security:
- without authentication and without privacy (noAuthNoPriv)
- with authentication but without privacy (authNoPriv)
- with authentication and with privacy (authPriv)
These three values are ordered such that noAuthNoPriv is less than
authNoPriv and authNoPriv is less than authPriv.
Every message has an associated securityLevel. All Subsystems
(Message Processing, Security, Access Control) and applications are
REQUIRED to either supply a value of securityLevel or to abide by the
supplied value of securityLevel while processing the message and its
contents.
4. Abstract Service Interfaces
Abstract service interfaces have been defined to describe the
conceptual interfaces between the various subsystems within an SNMP
entity. The abstract service interfaces are intended to help clarify
the externally observable behavior of SNMP entities, and are not
intended to constrain the structure or organization of
implementations in any way. Most specifically, they should not be
interpreted as APIs or as requirements statements for APIs.
These abstract service interfaces are defined by a set of primitives
that define the services provided and the abstract data elements that
are to be passed when the services are invoked. This section lists
the primitives that have been defined for the various subsystems.
4.1. Dispatcher Primitives
The Dispatcher typically provides services to the SNMP applications
via its PDU Dispatcher. This section describes the primitives
provided by the PDU Dispatcher.
4.1.1. Generate Outgoing Request or Notification
The PDU Dispatcher provides the following primitive for an
application to send an SNMP Request or Notification to another SNMP
entity:
statusInformation = -- sendPduHandle if success
-- errorIndication if failure
sendPdu(
IN transportDomain -- transport domain to be used
IN transportAddress -- transport address to be used
IN messageProcessingModel -- typically, SNMP version
IN securityModel -- Security Model to use
IN securityName -- on behalf of this principal
IN securityLevel -- Level of Security requested
IN contextEngineID -- data from/at this entity
IN contextName -- data from/in this context
IN pduVersion -- the version of the PDU
IN PDU -- SNMP Protocol Data Unit
IN expectResponse -- TRUE or FALSE
)
4.1.2. Process Incoming Request or Notification PDU
The PDU Dispatcher provides the following primitive to pass an
incoming SNMP PDU to an application:
processPdu( -- process Request/Notification PDU
IN messageProcessingModel -- typically, SNMP version
IN securityModel -- Security Model in use
IN securityName -- on behalf of this principal
IN securityLevel -- Level of Security
IN contextEngineID -- data from/at this SNMP entity
IN contextName -- data from/in this context
IN pduVersion -- the version of the PDU
IN PDU -- SNMP Protocol Data Unit
IN maxSizeResponseScopedPDU -- maximum size of the Response PDU
IN stateReference -- reference to state information
) -- needed when sending a response
4.1.3. Generate Outgoing Response
The PDU Dispatcher provides the following primitive for an
application to return an SNMP Response PDU to the PDU Dispatcher:
result = -- SUCCESS or FAILURE
returnResponsePdu(
IN messageProcessingModel -- typically, SNMP version
IN securityModel -- Security Model in use
IN securityName -- on behalf of this principal
IN securityLevel -- same as on incoming request
IN contextEngineID -- data from/at this SNMP entity
IN contextName -- data from/in this context
IN pduVersion -- the version of the PDU
IN PDU -- SNMP Protocol Data Unit
IN maxSizeResponseScopedPDU -- maximum size sender can accept
IN stateReference -- reference to state information
-- as presented with the request
IN statusInformation -- success or errorIndication
) -- error counter OID/value if error
4.1.4. Process Incoming Response PDU
The PDU Dispatcher provides the following primitive to pass an
incoming SNMP Response PDU to an application:
processResponsePdu( -- process Response PDU
IN messageProcessingModel -- typically, SNMP version
IN securityModel -- Security Model in use
IN securityName -- on behalf of this principal
IN securityLevel -- Level of Security
IN contextEngineID -- data from/at this SNMP entity
IN contextName -- data from/in this context
IN pduVersion -- the version of the PDU
IN PDU -- SNMP Protocol Data Unit
IN statusInformation -- success or errorIndication
IN sendPduHandle -- handle from sendPdu
)
4.1.5. Registering Responsibility for Handling SNMP PDUs
Applications can register/unregister responsibility for a specific
contextEngineID, for specific pduTypes, with the PDU Dispatcher
according to the following primitives. The list of particular
pduTypes that an application can register for is determined by the
Message Processing Model(s) supported by the SNMP entity that
contains the PDU Dispatcher.
statusInformation = -- success or errorIndication
registerContextEngineID(
IN contextEngineID -- take responsibility for this one
IN pduType -- the pduType(s) to be registered
)
unregisterContextEngineID(
IN contextEngineID -- give up responsibility for this one
IN pduType -- the pduType(s) to be unregistered
)
Note that realizations of the registerContextEngineID and
unregisterContextEngineID abstract service interfaces may provide
implementation-specific ways for applications to register/deregister
responsibility for all possible values of the contextEngineID or
pduType parameters.
4.2. Message Processing Subsystem Primitives
The Dispatcher interacts with a Message Processing Model to process a
specific version of an SNMP Message. This section describes the
primitives provided by the Message Processing Subsystem.
4.2.1. Prepare Outgoing SNMP Request or Notification Message
The Message Processing Subsystem provides this service primitive for
preparing an outgoing SNMP Request or Notification Message:
statusInformation = -- success or errorIndication
prepareOutgoingMessage(
IN transportDomain -- transport domain to be used
IN transportAddress -- transport address to be used
IN messageProcessingModel -- typically, SNMP version
IN securityModel -- Security Model to use
IN securityName -- on behalf of this principal
IN securityLevel -- Level of Security requested
IN contextEngineID -- data from/at this entity
IN contextName -- data from/in this context
IN pduVersion -- the version of the PDU
IN PDU -- SNMP Protocol Data Unit
IN expectResponse -- TRUE or FALSE
IN sendPduHandle -- the handle for matching
-- incoming responses
OUT destTransportDomain -- destination transport domain
OUT destTransportAddress -- destination transport address
OUT outgoingMessage -- the message to send
OUT outgoingMessageLength -- its length
)
4.2.2. Prepare an Outgoing SNMP Response Message
The Message Processing Subsystem provides this service primitive for
preparing an outgoing SNMP Response Message:
result = -- SUCCESS or FAILURE
prepareResponseMessage(
IN messageProcessingModel -- typically, SNMP version
IN securityModel -- same as on incoming request
IN securityName -- same as on incoming request
IN securityLevel -- same as on incoming request
IN contextEngineID -- data from/at this SNMP entity
IN contextName -- data from/in this context
IN pduVersion -- the version of the PDU
IN PDU -- SNMP Protocol Data Unit
IN maxSizeResponseScopedPDU -- maximum size able to accept
IN stateReference -- reference to state information
-- as presented with the request
IN statusInformation -- success or errorIndication
-- error counter OID/value if error
OUT destTransportDomain -- destination transport domain
OUT destTransportAddress -- destination transport address
OUT outgoingMessage -- the message to send
OUT outgoingMessageLength -- its length
)
4.2.3. Prepare Data Elements from an Incoming SNMP Message
The Message Processing Subsystem provides this service primitive for
preparing the abstract data elements from an incoming SNMP message:
result = -- SUCCESS or errorIndication
prepareDataElements(
IN transportDomain -- origin transport domain
IN transportAddress -- origin transport address
IN wholeMsg -- as received from the network
IN wholeMsgLength -- as received from the network
OUT messageProcessingModel -- typically, SNMP version
OUT securityModel -- Security Model to use
OUT securityName -- on behalf of this principal
OUT securityLevel -- Level of Security requested
OUT contextEngineID -- data from/at this entity
OUT contextName -- data from/in this context
OUT pduVersion -- the version of the PDU
OUT PDU -- SNMP Protocol Data Unit
OUT pduType -- SNMP PDU type
OUT sendPduHandle -- handle for matched request
OUT maxSizeResponseScopedPDU -- maximum size sender can accept
OUT statusInformation -- success or errorIndication
-- error counter OID/value if error
OUT stateReference -- reference to state information
-- to be used for possible Response
)
4.3. Access Control Subsystem Primitives
Applications are the typical clients of the service(s) of the Access
Control Subsystem.
The following primitive is provided by the Access Control Subsystem
to check if access is allowed:
statusInformation = -- success or errorIndication
isAccessAllowed(
IN securityModel -- Security Model in use
IN securityName -- principal who wants to access
IN securityLevel -- Level of Security
IN viewType -- read, write, or notify view
IN contextName -- context containing variableName
IN variableName -- OID for the managed object
)
4.4. Security Subsystem Primitives
The Message Processing Subsystem is the typical client of the
services of the Security Subsystem.
4.4.1. Generate a Request or Notification Message
The Security Subsystem provides the following primitive to generate a
Request or Notification message:
statusInformation =
generateRequestMsg(
IN messageProcessingModel -- typically, SNMP version
IN globalData -- message header, admin data
IN maxMessageSize -- of the sending SNMP entity
IN securityModel -- for the outgoing message
IN securityEngineID -- authoritative SNMP entity
IN securityName -- on behalf of this principal
IN securityLevel -- Level of Security requested
IN scopedPDU -- message (plaintext) payload
OUT securityParameters -- filled in by Security Module
OUT wholeMsg -- complete generated message
OUT wholeMsgLength -- length of the generated message
)
4.4.2. Process Incoming Message
The Security Subsystem provides the following primitive to process an
incoming message:
statusInformation = -- errorIndication or success
-- error counter OID/value if error
processIncomingMsg(
IN messageProcessingModel -- typically, SNMP version
IN maxMessageSize -- of the sending SNMP entity
IN securityParameters -- for the received message
IN securityModel -- for the received message
IN securityLevel -- Level of Security
IN wholeMsg -- as received on the wire
IN wholeMsgLength -- length as received on the wire
OUT securityEngineID -- identification of the principal
OUT securityName -- identification of the principal
OUT scopedPDU, -- message (plaintext) payload
OUT maxSizeResponseScopedPDU -- maximum size sender can handle
OUT securityStateReference -- reference to security state
) -- information, needed for response
4.4.3. Generate a Response Message
The Security Subsystem provides the following primitive to generate a
Response message:
statusInformation =
generateResponseMsg(
IN messageProcessingModel -- typically, SNMP version
IN globalData -- message header, admin data
IN maxMessageSize -- of the sending SNMP entity
IN securityModel -- for the outgoing message
IN securityEngineID -- authoritative SNMP entity
IN securityName -- on behalf of this principal
IN securityLevel -- for the outgoing message
IN scopedPDU -- message (plaintext) payload
IN securityStateReference -- reference to security state
-- information from original request
OUT securityParameters -- filled in by Security Module
OUT wholeMsg -- complete generated message
OUT wholeMsgLength -- length of the generated message
)
4.5. Common Primitives
These primitive(s) are provided by multiple Subsystems.
4.5.1. Release State Reference Information
All Subsystems which pass stateReference information also provide a
primitive to release the memory that holds the referenced state
information:
stateRelease(
IN stateReference -- handle of reference to be released
)
4.6. Scenario Diagrams
4.6.1. Command Generator or Notification Originator
This diagram shows how a Command Generator or Notification Originator
application requests that a PDU be sent, and how the response is
returned (asynchronously) to that application.
Command Dispatcher Message Security
Generator | Processing Model
| | Model |
| sendPdu | | |
|------------------->| | |
| | prepareOutgoingMessage | |
: |----------------------->| |
: | | generateRequestMsg |
: | |-------------------->|
: | | |
: | |<--------------------|
: | | |
: |<-----------------------| |
: | | |
: |------------------+ | |
: | Send SNMP | | |
: | Request Message | | |
: | to Network | | |
: | v | |
: : : : :
: : : : :
: : : : :
: | | | |
: | Receive SNMP | | |
: | Response Message | | |
: | from Network | | |
: |<-----------------+ | |
: | | |
: | prepareDataElements | |
: |----------------------->| |
: | | processIncomingMsg |
: | |-------------------->|
: | | |
: | |<--------------------|
: | | |
: |<-----------------------| |
| processResponsePdu | | |
|<-------------------| | |
| | | |
4.6.2. Scenario Diagram for a Command Responder Application
This diagram shows how a Command Responder or Notification Receiver
application registers for handling a pduType, how a PDU is dispatched
to the application after a SNMP message is received, and how the
Response is (asynchronously) send back to the network.
Command Dispatcher Message Security
Responder | Processing Model
| | Model |
| | | |
| registerContextEngineID | | |
|------------------------>| | |
|<------------------------| | | |
| | Receive SNMP | | |
: | Message | | |
: | from Network | | |
: |<-------------+ | |
: | | |
: |prepareDataElements | |
: |------------------->| |
: | | processIncomingMsg |
: | |------------------->|
: | | |
: | |<-------------------|
: | | |
: |<-------------------| |
| processPdu | | |
|<------------------------| | |
| | | |
: : : :
: : : :
| returnResponsePdu | | |
|------------------------>| | |
: | prepareResponseMsg | |
: |------------------->| |
: | |generateResponseMsg |
: | |------------------->|
: | | |
: | |<-------------------|
: | | |
: |<-------------------| |
: | | |
: |--------------+ | |
: | Send SNMP | | |
: | Message | | |
: | to Network | | |
: | v | |
5. Managed Object Definitions for SNMP Management Frameworks
SNMP-FRAMEWORK-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, OBJECT-TYPE,
OBJECT-IDENTITY,
snmpModules FROM SNMPv2-SMI
TEXTUAL-CONVENTION FROM SNMPv2-TC
MODULE-COMPLIANCE, OBJECT-GROUP FROM SNMPv2-CONF;
snmpFrameworkMIB MODULE-IDENTITY
LAST-UPDATED "9901190000Z" -- 19 January 1999
ORGANIZATION "SNMPv3 Working Group"
CONTACT-INFO "WG-EMail:
snmpv3@tis.com
Subscribe:
majordomo@tis.com
In message body: subscribe snmpv3
Chair: Russ Mundy
TIS Labs at Network Associates
postal: 3060 Washington Rd
Glenwood MD 21738
USA
EMail:
mundy@tis.com
phone: +1 301-854-6889
Co-editor Dave Harrington
Cabletron Systems, Inc.
postal: Post Office Box 5005
Mail Stop: Durham
35 Industrial Way
Rochester, NH 03867-5005
USA
EMail:
dbh@ctron.com
phone: +1 603-337-7357
Co-editor Randy Presuhn
BMC Software, Inc.
postal: 965 Stewart Drive
Sunnyvale, CA 94086
USA
EMail:
randy_presuhn@bmc.com
phone: +1 408-616-3100
Co-editor: Bert Wijnen
IBM T.J. Watson Research
postal: Schagen 33
3461 GL Linschoten
Netherlands
EMail:
wijnen@vnet.ibm.com
phone: +31 348-432-794
"
DESCRIPTION "The SNMP Management Architecture MIB"
-- Revision History
REVISION "9901190000Z" -- 19 January 1999
DESCRIPTION "Updated editors' addresses, fixed typos.
Published as
RFC2571.
"
REVISION "9711200000Z" -- 20 November 1997
DESCRIPTION "The initial version, published in
RFC2271.
"
::= { snmpModules 10 }
-- Textual Conventions used in the SNMP Management Architecture ***
SnmpEngineID ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION "An SNMP engine's administratively-unique identifier.
Objects of this type are for identification, not for
addressing, even though it is possible that an
address may have been used in the generation of
a specific value.
The value for this object may not be all zeros or
all 'ff'H or the empty (zero length) string.
The initial value for this object may be configured
via an operator console entry or via an algorithmic
function. In the latter case, the following
example algorithm is recommended.
In cases where there are multiple engines on the
same system, the use of this algorithm is NOT
appropriate, as it would result in all of those
engines ending up with the same ID value.
1) The very first bit is used to indicate how the
rest of the data is composed.
0 - as defined by enterprise using former methods
that existed before SNMPv3. See item 2 below.
1 - as defined by this architecture, see item 3
below.
Note that this allows existing uses of the
engineID (also known as AgentID [
RFC1910]) to
co-exist with any new uses.
2) The snmpEngineID has a length of 12 octets.
The first four octets are set to the binary
equivalent of the agent's SNMP management
private enterprise number as assigned by the
Internet Assigned Numbers Authority (IANA).
For example, if Acme Networks has been assigned
{ enterprises 696 }, the first four octets would
be assigned '000002b8'H.
The remaining eight octets are determined via
one or more enterprise-specific methods. Such
methods must be designed so as to maximize the
possibility that the value of this object will
be unique in the agent's administrative domain.
For example, it may be the IP address of the SNMP
entity, or the MAC address of one of the
interfaces, with each address suitably padded
with random octets. If multiple methods are
defined, then it is recommended that the first
octet indicate the method being used and the
remaining octets be a function of the method.
3) The length of the octet strings varies.
The first four octets are set to the binary
equivalent of the agent's SNMP management
private enterprise number as assigned by the
Internet Assigned Numbers Authority (IANA).
For example, if Acme Networks has been assigned
{ enterprises 696 }, the first four octets would
be assigned '000002b8'H.
The very first bit is set to 1. For example, the
above value for Acme Networks now changes to be
'800002b8'H.
The fifth octet indicates how the rest (6th and
following octets) are formatted. The values for
the fifth octet are:
0 - reserved, unused.
1 - IPv4 address (4 octets)
lowest non-special IP address
2 - IPv6 address (16 octets)
lowest non-special IP address
3 - MAC address (6 octets)
lowest IEEE MAC address, canonical
order
4 - Text, administratively assigned
Maximum remaining length 27
5 - Octets, administratively assigned
Maximum remaining length 27
6-127 - reserved, unused
127-255 - as defined by the enterprise
Maximum remaining length 27
"
SYNTAX OCTET STRING (SIZE(5..32))
SnmpSecurityModel ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION "An identifier that uniquely identifies a
securityModel of the Security Subsystem within the
SNMP Management Architecture.
The values for securityModel are allocated as
follows:
- The zero value is reserved.
- Values between 1 and 255, inclusive, are reserved
for standards-track Security Models and are
managed by the Internet Assigned Numbers Authority
(IANA).
- Values greater than 255 are allocated to
enterprise-specific Security Models. An
enterprise-specific securityModel value is defined
to be:
enterpriseID * 256 + security model within
enterprise
For example, the fourth Security Model defined by
the enterprise whose enterpriseID is 1 would be
260.
This scheme for allocation of securityModel
values allows for a maximum of 255 standards-
based Security Models, and for a maximum of
255 Security Models per enterprise.
It is believed that the assignment of new
securityModel values will be rare in practice
because the larger the number of simultaneously
utilized Security Models, the larger the
chance that interoperability will suffer.
Consequently, it is believed that such a range
will be sufficient. In the unlikely event that
the standards committee finds this number to be
insufficient over time, an enterprise number
can be allocated to obtain an additional 255
possible values.
Note that the most significant bit must be zero;
hence, there are 23 bits allocated for various
organizations to design and define non-standard
securityModels. This limits the ability to
define new proprietary implementations of Security
Models to the first 8,388,608 enterprises.
It is worthwhile to note that, in its encoded
form, the securityModel value will normally
require only a single byte since, in practice,
the leftmost bits will be zero for most messages
and sign extension is suppressed by the encoding
rules.
As of this writing, there are several values
of securityModel defined for use with SNMP or
reserved for use with supporting MIB objects.
They are as follows:
0 reserved for 'any'
1 reserved for SNMPv1
2 reserved for SNMPv2c
3 User-Based Security Model (USM)
"
SYNTAX INTEGER(0 .. 2147483647)
SnmpMessageProcessingModel ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION "An identifier that uniquely identifies a Message
Processing Model of the Message Processing
Subsystem within a SNMP Management Architecture.
The values for messageProcessingModel are
allocated as follows:
- Values between 0 and 255, inclusive, are
reserved for standards-track Message Processing
Models and are managed by the Internet Assigned
Numbers Authority (IANA).
- Values greater than 255 are allocated to
enterprise-specific Message Processing Models.
An enterprise messageProcessingModel value is
defined to be:
enterpriseID * 256 +
messageProcessingModel within enterprise
For example, the fourth Message Processing Model
defined by the enterprise whose enterpriseID
is 1 would be 260.
This scheme for allocating messageProcessingModel
values allows for a maximum of 255 standards-
based Message Processing Models, and for a
maximum of 255 Message Processing Models per
enterprise.
It is believed that the assignment of new
messageProcessingModel values will be rare
in practice because the larger the number of
simultaneously utilized Message Processing Models,
the larger the chance that interoperability
will suffer. It is believed that such a range
will be sufficient. In the unlikely event that
the standards committee finds this number to be
insufficient over time, an enterprise number
can be allocated to obtain an additional 256
possible values.
Note that the most significant bit must be zero;
hence, there are 23 bits allocated for various
organizations to design and define non-standard
messageProcessingModels. This limits the ability
to define new proprietary implementations of
Message Processing Models to the first 8,388,608
enterprises.
It is worthwhile to note that, in its encoded
form, the messageProcessingModel value will
normally require only a single byte since, in
practice, the leftmost bits will be zero for
most messages and sign extension is suppressed
by the encoding rules.
As of this writing, there are several values of
messageProcessingModel defined for use with SNMP.
They are as follows:
0 reserved for SNMPv1
1 reserved for SNMPv2c
2 reserved for SNMPv2u and SNMPv2*
3 reserved for SNMPv3
"
SYNTAX INTEGER(0 .. 2147483647)
SnmpSecurityLevel ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION "A Level of Security at which SNMP messages can be
sent or with which operations are being processed;
in particular, one of:
noAuthNoPriv - without authentication and
without privacy,
authNoPriv - with authentication but
without privacy,
authPriv - with authentication and
with privacy.
These three values are ordered such that
noAuthNoPriv is less than authNoPriv and
authNoPriv is less than authPriv.
"
SYNTAX INTEGER { noAuthNoPriv(1),
authNoPriv(2),
authPriv(3)
}
SnmpAdminString ::= TEXTUAL-CONVENTION
DISPLAY-HINT "255a"
STATUS current
DESCRIPTION "An octet string containing administrative
information, preferably in human-readable form.
To facilitate internationalization, this
information is represented using the ISO/IEC
IS 10646-1 character set, encoded as an octet
string using the UTF-8 transformation format
described in [
RFC2279].
Since additional code points are added by
amendments to the 10646 standard from time
to time, implementations must be prepared to
encounter any code point from 0x00000000 to
0x7fffffff. Byte sequences that do not
correspond to the valid UTF-8 encoding of a
code point or are outside this range are
prohibited.
The use of control codes should be avoided.
When it is necessary to represent a newline,
the control code sequence CR LF should be used.
The use of leading or trailing white space should
be avoided.
For code points not directly supported by user
interface hardware or software, an alternative
means of entry and display, such as hexadecimal,
may be provided.
For information encoded in 7-bit US-ASCII,
the UTF-8 encoding is identical to the
US-ASCII encoding.
UTF-8 may require multiple bytes to represent a
single character / code point; thus the length
of this object in octets may be different from
the number of characters encoded. Similarly,
size constraints refer to the number of encoded
octets, not the number of characters represented
by an encoding.
Note that when this TC is used for an object that
is used or envisioned to be used as an index, then
a SIZE restriction MUST be specified so that the
number of sub-identifiers for any object instance
does not exceed the limit of 128, as defined by
[
RFC1905].
Note that the size of an SnmpAdminString object is
measured in octets, not characters.
"
SYNTAX OCTET STRING (SIZE (0..255))
-- Administrative assignments ***************************************
snmpFrameworkAdmin
OBJECT IDENTIFIER ::= { snmpFrameworkMIB 1 }
snmpFrameworkMIBObjects
OBJECT IDENTIFIER ::= { snmpFrameworkMIB 2 }
snmpFrameworkMIBConformance
OBJECT IDENTIFIER ::= { snmpFrameworkMIB 3 }
-- the snmpEngine Group ********************************************
snmpEngine OBJECT IDENTIFIER ::= { snmpFrameworkMIBObjects 1 }
snmpEngineID OBJECT-TYPE
SYNTAX SnmpEngineID
MAX-ACCESS read-only
STATUS current
DESCRIPTION "An SNMP engine's administratively-unique identifier.
"
::= { snmpEngine 1 }
snmpEngineBoots OBJECT-TYPE
SYNTAX INTEGER (1..2147483647)
MAX-ACCESS read-only
STATUS current
DESCRIPTION "The number of times that the SNMP engine has
(re-)initialized itself since snmpEngineID
was last configured.
"
::= { snmpEngine 2 }
snmpEngineTime OBJECT-TYPE
SYNTAX INTEGER (0..2147483647)
UNITS "seconds"
MAX-ACCESS read-only
STATUS current
DESCRIPTION "The number of seconds since the value of
the snmpEngineBoots object last changed.
When incrementing this object's value would
cause it to exceed its maximum,
snmpEngineBoots is incremented as if a
re-initialization had occurred, and this
object's value consequently reverts to zero.
"
::= { snmpEngine 3 }
snmpEngineMaxMessageSize OBJECT-TYPE
SYNTAX INTEGER (484..2147483647)
MAX-ACCESS read-only
STATUS current
DESCRIPTION "The maximum length in octets of an SNMP message
which this SNMP engine can send or receive and
process, determined as the minimum of the maximum
message size values supported among all of the
transports available to and supported by the engine.
"
::= { snmpEngine 4 }
-- Registration Points for Authentication and Privacy Protocols **
snmpAuthProtocols OBJECT-IDENTITY
STATUS current
DESCRIPTION "Registration point for standards-track
authentication protocols used in SNMP Management
Frameworks.
"
::= { snmpFrameworkAdmin 1 }
snmpPrivProtocols OBJECT-IDENTITY
STATUS current
DESCRIPTION "Registration point for standards-track privacy
protocols used in SNMP Management Frameworks.
"
::= { snmpFrameworkAdmin 2 }
-- Conformance information ******************************************
snmpFrameworkMIBCompliances
OBJECT IDENTIFIER ::= {snmpFrameworkMIBConformance 1}
snmpFrameworkMIBGroups
OBJECT IDENTIFIER ::= {snmpFrameworkMIBConformance 2}
-- compliance statements
snmpFrameworkMIBCompliance MODULE-COMPLIANCE
STATUS current
DESCRIPTION "The compliance statement for SNMP engines which
implement the SNMP Management Framework MIB.
"
MODULE -- this module
MANDATORY-GROUPS { snmpEngineGroup }
::= { snmpFrameworkMIBCompliances 1 }
-- units of conformance
snmpEngineGroup OBJECT-GROUP
OBJECTS {
snmpEngineID,
snmpEngineBoots,
snmpEngineTime,
snmpEngineMaxMessageSize
}
STATUS current
DESCRIPTION "A collection of objects for identifying and
determining the configuration and current timeliness
values of an SNMP engine.
"
::= { snmpFrameworkMIBGroups 1 }
END
6. IANA Considerations
This document defines three number spaces administered by IANA, one
for security models, another for message processing models, and a
third for SnmpEngineID formats.
6.1. Security Models
The SnmpSecurityModel TEXTUAL-CONVENTION values managed by IANA are
in the range from 0 to 255 inclusive, and are reserved for
standards-track Security Models. If this range should in the future
prove insufficient, an enterprise number can be allocated to obtain
an additional 255 possible values.
As of this writing, there are several values of securityModel defined
for use with SNMP or reserved for use with supporting MIB objects.
They are as follows:
0 reserved for 'any'
1 reserved for SNMPv1
2 reserved for SNMPv2c
3 User-Based Security Model (USM)
6.2. Message Processing Models
The SnmpMessageProcessingModel TEXTUAL-CONVENTION values managed by
IANA are in the range 0 to 255, inclusive. Each value uniquely
identifies a standards-track Message Processing Model of the Message
Processing Subsystem within a SNMP Management Architecture.
Should this range prove insufficient in the future, an enterprise
number may be obtained for the standards committee to get an
additional 256 possible values.
As of this writing, there are several values of
messageProcessingModel defined for use with SNMP. They are as
follows:
0 reserved for SNMPv1
1 reserved for SNMPv2c
2 reserved for SNMPv2u and SNMPv2*
3 reserved for SNMPv3
6.3. SnmpEngineID Formats
The SnmpEngineID TEXTUAL-CONVENTION's fifth octet contains a format
identifier. The values managed by IANA are in the range 6 to 127,
inclusive. Each value uniquely identifies a standards-track
SnmpEngineID format.
7. 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.
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.
8. Acknowledgements
This document is the result of the efforts of the SNMPv3 Working
Group. Some special thanks are in order to the following SNMPv3 WG
members:
Harald Tveit Alvestrand (Maxware)
Dave Battle (SNMP Research, Inc.)
Alan Beard (Disney Worldwide Services)
Paul Berrevoets (SWI Systemware/Halcyon Inc.)
Martin Bjorklund (Ericsson)
Uri Blumenthal (IBM T.J. Watson Research Center)
Jeff Case (SNMP Research, Inc.)
John Curran (BBN)
Mike Daniele (Compaq Computer Corporation)
T. Max Devlin (Eltrax Systems)
John Flick (Hewlett Packard)
Rob Frye (MCI)
Wes Hardaker (U.C.Davis, Information Technology - D.C.A.S.)
David Harrington (Cabletron Systems Inc.)
Lauren Heintz (BMC Software, Inc.)
N.C. Hien (IBM T.J. Watson Research Center)
Michael Kirkham (InterWorking Labs, Inc.)
Dave Levi (SNMP Research, Inc.)
Louis A Mamakos (UUNET Technologies Inc.)
Joe Marzot (Nortel Networks)
Paul Meyer (Secure Computing Corporation)
Keith McCloghrie (Cisco Systems)
Bob Moore (IBM)
Russ Mundy (TIS Labs at Network Associates)
Bob Natale (ACE*COMM Corporation)
Mike O'Dell (UUNET Technologies Inc.)
Dave Perkins (DeskTalk)
Peter Polkinghorne (Brunel University)
Randy Presuhn (BMC Software, Inc.)
David Reeder (TIS Labs at Network Associates)
David Reid (SNMP Research, Inc.)
Aleksey Romanov (Quality Quorum)
Shawn Routhier (Epilogue)
Juergen Schoenwaelder (TU Braunschweig)
Bob Stewart (Cisco Systems)
Mike Thatcher (Independent Consultant)
Bert Wijnen (IBM T.J. Watson Research Center)
The document is based on recommendations of the IETF Security and
Administrative Framework Evolution for SNMP Advisory Team. Members
of that Advisory Team were:
David Harrington (Cabletron Systems Inc.)
Jeff Johnson (Cisco Systems)
David Levi (SNMP Research Inc.)
John Linn (Openvision)
Russ Mundy (Trusted Information Systems) chair
Shawn Routhier (Epilogue)
Glenn Waters (Nortel)
Bert Wijnen (IBM T. J. Watson Research Center)
As recommended by the Advisory Team and the SNMPv3 Working Group
Charter, the design incorporates as much as practical from previous
RFCs and drafts. As a result, special thanks are due to the authors
of previous designs known as SNMPv2u and SNMPv2*:
Jeff Case (SNMP Research, Inc.)
David Harrington (Cabletron Systems Inc.)
David Levi (SNMP Research, Inc.)
Keith McCloghrie (Cisco Systems)
Brian O'Keefe (Hewlett Packard)
Marshall T. Rose (Dover Beach Consulting)
Jon Saperia (BGS Systems Inc.)
Steve Waldbusser (International Network Services)
Glenn W. Waters (Bell-Northern Research Ltd.)
9. Security Considerations
This document describes how an implementation can include a Security
Model to protect management messages and an Access Control Model to
control access to management information.
The level of security provided is determined by the specific Security
Model implementation(s) and the specific Access Control Model
implementation(s) used.
Applications have access to data which is not secured. Applications
SHOULD take reasonable steps to protect the data from disclosure.
It is the responsibility of the purchaser of an implementation to
ensure that:
1) an implementation complies with the rules defined by this
architecture,
2) the Security and Access Control Models utilized satisfy the
security and access control needs of the organization,
3) the implementations of the Models and Applications comply with
the model and application specifications,
4) and the implementation protects configuration secrets from
inadvertent disclosure.
This document also contains a MIB definition module. None of the
objects defined is writable, and the information they represent is
not deemed to be particularly sensitive. However, if they are deemed
sensitive in a particular environment, access to them should be
restricted through the use of appropriately configured Security and
Access Control models.
10. References
[