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					Glossary of SNMP Terms and
                  Acronyms
This “Glossary of SNMP Terms and Acronyms” is a compilation of material gathered over time from
numerous sources. It is provided “as-is” and in good faith, without any warranty as to the accuracy or
currency of any definition or other information contained herein. Please contact Tektronix if you believe
that any of the included material violates any proprietary rights of other parties.
      SNMP Terms and Acronyms
                                      Glossary




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     A

Abstract Service Interfaces – Abstract service interfaces have been           Address Translation – The process of translating a Network Layer to a
defined to describe the conceptual interfaces between the various             corresponding physical address for a device.
subsystems within an SNMP entity. These abstract service interfaces are
defined by a set of primitives that define the services provided and the      Agent – a) Software running on the device being managed that allows it
abstract data elements that are to be passed when the services are            to be managed. Sets managed device configuration parameters. Reports
invoked. This section lists the primitives that have been defined for the     current operation statistics when requested by the manager or when a
various subsystems.                                                           trap is generated base on previous manager setup commands. b) Talks
                                                                              with manager which is the network manager interface software running
Abstract Syntax Notation One – See ASN.1.                                     on the network management computer. c) An interface to a managed
                                                                              object, such as a workstation or an application running on a workstation,
Access Control – a) Controls the access to Management Information             that responds to a request from a manager. d) SNMP Agent Block
Buses (MIB) objects. b) An access control model may define MIB                Diagram:
modules used during processing and to allow the remote configuration of
access control policies. c) Restriction of access to MIB objects either in
scope or function or both, on the basis of party.
Access Control (SNMP) – Restriction of the operations that may be
performed for a party and of the data that the party may access.
Access Control List (ACL) – An indication of what actions
(aclPrivileges) may be performed by a given party (aclTraget) on behalf of
another party (aclSubject) within a given context (aclResources).
Access Control Model – a) Defined in RFC2271. b) Defines a particular
access decision function in order to support decisions regarding access
rights.
Access Control Subsystem – a) Defined in RFC2271. b) Provides
authentication services by means of one or more access control models.
Access Control Subsystem Primitives – a) Applications are the typical
clients of the service(s) of the Access Control Subsystem. b) The             Alarm – A variable, sampling interval, and a Rising and Falling
following primitive is provided by the Access Control Subsystem to check      Threshold. When a threshold is crossed, an event may be triggered.
if access is allowed:
                                                                              ANSI (American National Standards Institute)
statusInformation =                 -- success or errorIndication             API (Application Programming Interface)
 isAccessAllowed(
 IN      securityModel              --   Security Model in use                Application – a) A component of an SNMP entity which determines the
 IN      securityName               --   principal who wants to access        function of an entity. b) Applications include: Command Generator –
 IN      securityLevel              --   Level of Security                    manager application which generates get or set commands; Command
 IN      viewType                   --   read, write, or notify view          Responder – agent application which responds to manager get or set
 IN      contextName                --   context containing variableName      commands; Notification Originator – agent application which generates
 IN      variableName               --   OID for the managed object           asynchronous traps; Notification Receiver – manager application which
         )                                                                    responds to agent generated asynchronous traps; Proxy Forwarder –
                                                                              application which responds to commands between entities.
Access Mode – A MIB access level of READ-ONLY, READ-WRITE or
NONE.                                                                         Application Layer – a) Seventh layer of the OSI network management
                                                                              model. b) Functions that cause end to end data transfers such as email,
Accounting Management – a) One of the five OSI systems                        file transfers or the SNMP manager/agent.
management functional areas (SMFAs). b ) Consists of facilities that
enable the detection, isolation and correction of abnormal operation of the   ARP (Address Resolution Protocol) – A protocol that dynamically
OSI environment.                                                              discovers the physical address of a system, given its IP address.

ACSE (Association Control Service Elements)                                   ARPANET (Advanced Research Projects Agency)




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AS (Autonomous System) – A collection of routers under the control of
a single administrative authority, and using a common Interior Gateway
Protocol.
ASN.1 (Abstract Syntax Notation One) – a) A formal language used to
define syntax. b) In the case of SNMP, ASN.1 notation is used to define
the format of SNMP protocol data units and of objects. c) A standard
language for describing data structures. ASN.1 does not depend on
computer architecture or implementation language. Therefore, it lets
programs exchange structured data over networks.
Asynchronous – In the EMANATE SNMP model, this terms means the
Master Agent passes requests to Subagents who then handle the request
allowing the Master Agent to accept new requests.
ATM (Asynchronous Transfer Mode) – A method of packaging and
switching information within 53-octet cells that will be deployed for both
local area network use and wide area networking.
AUI (Attachment Unit Interface) – A cable attaching a station‟s Ethernet
NIC to a transceiver that clamps onto a coaxial cable.
Authentication – a) In SNMP authentication means that the SNMP entity
can assert with certainty that the purported sender of a message is in fact
the sender of that message. b) Proof of the identity of the sender of a
message.
Availability – The percentage of time that a particular function or
application is available for users.




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     B

BER (Basic Encoding Rules) – a) Describe how SNMP data should be
encoded „on the wire‟ in such a way that machines with potentially very
different architectures can understand it. b) Specifies how bits of the
SNMP message (more specifically the PDU) are placed on the physical
layer medium. c) All SNMP encoded items consist of three concatenated
fields:




Big Endian – A format for the storage or transmission of data that places
the most significant byte (or bit) first.
Bind – Assign a value or series of possible values to an object or an
object instance.
Bridge – a) A functional unit that interconnects two local area networks
(LANs) that use the same logical link control protocol but may use
different medium access control protocols. b) A device that connects two
or more physical network components and forwards frames which have
source and destination addresses on different network components.
Bus – a) A LAN topology in which stations are attached to a shared
transmission medium. b) The medium is a linear cable; transmissions
propagate the length of the medium and are received by all stations.
Byte – A group of bits, usually eight, used to represent a character or
other date.




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       C

Cached Security Data – a) For each message received, the Security
Model caches the state information such that a Response message can
be generated using the same security information, even if the Local
Configuration Datastore is altered between the time of the incoming
request and the outgoing response. b) A Message Processing Model has
the responsibility for explicitly releasing the cached data if such data is no
longer needed. To enable this, an abstract securityStateReference data
element is passed from the Security Model to the Message Processing
Model. c) The cached security data may be implicitly released via the
generation of a response, or explicitly released by using the stateRelease
primitive.
Case Diagram – A figure that tracks the flow of incoming and outgoing
Protocol Data Units.
CCITT (International Telegraph and Telephone Consultative
Committee) – Original name for the ITU-TS. An organization formed to
coordinate the connection of telephony and data communications
facilities into international networks.
Channel – Packets that are selected by a set of filter expressions, it           Command Responder or Notification Receiver – This diagram shows
forms a logical data stream.                                                     how a Command Responder or Notification Receiver application registers
                                                                                 for handling a pduType, how a PDU is dispatched to the application after
CIM (Common Information Model) – A model that standardizes and                   a SNMP message is received, and how the Response is
associates various vendor specific data types and MIB managed objects            (asynchronously) send back to the network.
into a common standard.
Ciphertext – The output of an encryption algorithm; the encrypted form of
a message or data.
CLNP (Connectionless Network Protocol) – Data link layer protocol.
CLTS (Connectionless Transport Service) – OSI architecture
connectionless mechanism.
CMIP (Common Management Information Protocol) – The ISO-OSI
network management protocol.
CMIS (Common Management Information Service)
CMOT (Common Management Information Services and Protocol
over TCP/IP) – This was an attempt to incorporate, to the maximum
extent possible, the protocol (CMIP), services and database structure
being standardized by ISO for network management.
Columnar Object – a) An object that is part of an SNMP table. b) There
is one instance of the columnar object for each row in the table.                Common Information Model (CIM) – A model that standardizes and
Command Generator or Notification Originator Diagram – This                      associates various vendor specific data types and MIB managed objects
diagram shows how a Command Generator or Notification Originator                 into a common standard.
application requests that a PDU be sent, and how the response is                 Communications Architecture – The hardware and software structure
returned (asynchronously) to that application.                                   that implements the communications function.
                                                                                 Community – a) In the context of SNMP, a relationship between an
                                                                                 agent and a set of SNMP managers that defines security characteristics.
                                                                                 b) The community concept is a local one, defined at the agent. c) The
                                                                                 agent establishes one community for each desired combination of




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authentication, access control and proxy characteristics. d) Each              the management domain. The same item of management information can
community is given a unique (within this agent) community name and the         exist in multiple contexts. An item of management information may have
management stations within that community are provided with and must           multiple unique identifications. This occurs when an item of management
employ the community name in all get and set operations. e) The agent          information exists in multiple contexts, and this also occurs when a
may establish a number of communities, with overlapping management             context has multiple unique identifications. g) The combination of a
station memberships.                                                           contextEngineID and a contextName unambiguously identifies a context
                                                                               within an administrative domain; note that there may be multiple unique
Community String – An SNMP security password. There are three kinds            combinations of contextEngineID and contextName that unambiguously
of community strings:                                                          identify the same context.
                                                                               contextEngineID – Within an administrative domain, a contextEngineID
                                                                               uniquely identifies an SNMP entity that may realize an instance of a
                                                                               context with a particular contextName.

Compiling – The process of importing a MIB file into an SNMP manager.          contextName – A contextName is used to name a context. Each
To compile properly, a MIB file must be formatted in a text file according     contextName MUST be unique within an SNMP entity.
to the Structure of Management Information (SMI) standard.                     COS (Change of State) Alarm – A telemetry alarm that is clearly labeled
Configuration Management – a) One of the five OSI system                       as reporting a change in status from clear to alarm or from alarm to clear.
management functional areas (SMFAs). b) Consists of facilities that            Coserver – The functional equivalent of a database server that operates
exercise control over, identify, collect data from, and provide data to        on a single node.
managed objects for the purpose of assisting in providing for continuous
operation of interconnections services.                                        Counter – a) A non-negative integer which may be incremented but not
                                                                               decremented. b) The maximum value is determined by the number of bits
Conformance Statement – Defines the notation used to define                    assigned to the counter. c) When the counter reaches its maximum
acceptable lower and upper bounds for implementation.                          value, it wraps around and starts increasing again from zero. d) In
Connectionless Protocol – Allows packets to be routed individually             SNMPv1, all counters are 32 bits while SNMPv2 also allows for 64 bit
rather than through a pre-established connection. IP is a connectionless       counters.
protocol.                                                                      CPE (Convergence Protocol Entity)
Connection Oriented Protocol – Transmits packets through pre-                  CRC (Cyclic Redundancy Check) – a) An error detecting code in which
determined routes which are established at connection setup.                   the code is the remainder resulting from dividing the bits to be checked by
Context – a) A context is a collection of management information               a predetermined binary number. b) A mathematical function applied to
accessible by an SNMP entity. An item of management information may            the bits in a frame, and appended to the frame. The CRC is recalculated
exist in more than one context. An SNMP entity potentially has access to       when the frame is received. If the result differs from the appended value,
many contexts. b) Typically there are many instances of each managed           then the frame is discarded.
object type within a management domain. For simplicity, the method for         CSMA/CD (Carrier Sense Multiple Access with Collision Detection) –
identifying instances specified by the MIB model does not allow each           A simple media access control protocol. All stations listen to the medium.
instance to be distinguished amongst the set of all instances within a         A station wanting to send may do so if there is no signal on the medium.
management domain. Rather it allows each instance to be identified only        When two stations transmit simultaneously, both back off and retry after a
within some scope or “context”, where there are multiple such contexts         random time period.
within the management domain. c) Often, a context is a physical device,
or perhaps, a logical device although a context can also encompass             CSMIE/CMP (Common Management Information Service
multiple devices, or a subset of a single device, or even subsets on           Element/Common Management Information)
multiple devices, but a context is always defined as a subset of a single
                                                                               CVS (Concurrent Version System) – A front end to the revision control
SNMP entity. Thus in order to identify an individual item of management
                                                                               system. CVS keeps a single copy of shared files in a source „repository‟;
information within the management domain, its contextName and
                                                                               it contains all the information to permit extracting previous software
contextEngineID must be identified in addition to its object type for
                                                                               releases at any time based on either a symbolic revision tag or a date in
instance. d) For example, the managed object type ifDescr, is defined as
                                                                               the past.
the description of a network interface (if means interface). e) To identify
the description of device-X‟s first network interface, four pieces of          Cyclic Redundancy Check – See CRC.
information are needed: SnmpEngineID of the SNMP entity which
provides access to the management information at device-X; the
contextName of device-X; the managed object type (ifDescr); the
instance (.0). f) Each context has at least one unique identification within




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       D

Data Link Layer – a) The second layer of the OSI network management
model. b) Provides reliable communications between networked nodes
by providing addressing (MAC level addressing), framing and error
control for errors that occur in the physical layer.
Datagram – In packet switching, a packet, independent of other packets,
that carries information sufficient for routing from the originating data
terminal equipment (DTE) to the destination DTE without the necessity of
establishing a connection between the DTEs and the network.
DCE (Data Communications Equipment)
DEN (Directory Enabled Networking)
Deprecated – Status of a MIB variable, meaning that it still is supported,
but is being phased out.
Dispatcher – a) Defined in RFC2271. b) There is only one dispatcher in
an SNMP engine. c) It allows for concurrent support of multiple versions
of SNMP messages in the SNMP engine. d) It does the above by:
Sending and receiving SNMP messages to/from the network;
Determining the version of an SNMP message and interacting with the
corresponding Message Processing Model; Providing an abstract
interface to SNMP applications for delivery of a PDU to an application;
Providing an abstract interface for SNMP applications, which allows them
to send a PDU to a remote entity.
DisplayString – a) MIB object that is a printable text string rather than an
INTEGER value. b) Some MIB designers choose to use DisplayStrings
when the possible number of object variations are too great to number.
c) Designers should avoid DisplayStrings however because while they
are nice to display on monitors being read by humans, it is very difficult
for automatic tools to parse the text and use it.
DLCI (Data Link Connection Identifier) – In frame relay, a local numeric
identifier used to name a virtual circuit.
DMTF (Desktop Management Task Force)
DNS (Domain Naming Service) – A networked data base primarily used
to identify mail handlers and to resolve IP addresses from symbolic
names.
Dotted Decimal Notation – a) The format that uses a string of numbers
or their text equivalents separated by periods, to represent steps walking
through the MIB tree. b) There is only one path to each object, there
cannot be two paths that lead to the object.
DTE (Data Terminal Equipment)




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E

EGP (Exterior Gateway Protocol) – A protocol used to advertise            telemetry. The ability to filter unimportant events is essential for
the set of networks that can be reached within an autonomous              high-quality SNMP alarm management. b) A table entry that
system. EGP enables this information to be shared with other              identifies a notification message to be sent (in an InformRequest) as
autonomous systems.                                                       a result of an alarm.
End System – See ES.
ES (End System) – a) A device other than an intermediate system
attached to a subnetwork in an internet. b) End systems on different
subnetworks exchange data by transmitting the data through one or
more intermediate systems.
EMANATE SNMP Software (Enhanced MANagement Agent
Through Extension) – EMANATE Model




Encapsulate – The addition of control information by a protocol
entity to data obtained from a protocol user.
Encrypt – To convert plain text or data into unintelligible form by the
use of a code in such a manner that re-conversion to the original
form is possible.
Engine – A component of an SNMP entity which consists of a
message processing subsystem, a security subsystem, an access
control subsystem (as appropriate) and a dispatcher.
Entity – A network management element which consists of an
SNMP engine and one or more applications.
Entry Status – A table variable used to control row creation and
deletion.
Error Detecting Code – A code in which each coded
representation conforms to specific rules of construction so that their
violation indicates the presence of errors.
Error Rate – The number of errors per unit of time.
Event – a) In SNMP terms, any change of status in a managed
object in the network. SNMP equipment can generate traps for
many different kinds of events, not all of which are important for




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       F

Fault Management – a) One of the five OSI systems management
functional areas (SMFAs). b) Consists of facilities that enable the
detection, isolation and correction of abnormal operation of the OSI
environment.
FCS (Frame Check Sequence) – a) An error detecting code inserted as
a field in a block of data to be transmitted. b) The code servers to check
for errors upon reception of the data. c) A mathematical function applied
to the bits in a frame, and appended to the frame. The FCS is
recalculated when the frame is received. If the result differs from the
appended value, then the frame is discarded.
FDDI (Fiber Distributed Data Interface) – A standard for high-speed
data transfer across a dual ring.
Flow Control – A function performed by a receiving entity to limit the
amount or rate of data sent by a transmitting entity.
Frame – a) A group of bits that includes data plus one or more addresses
and other protocol control information. b) Generally refers to a protocol
data unit found at layer two (the Data Link Layer) of the OSI seven layer
model.
Frame Check Sequence – See FCS.
FTP (File Transfer Protocol)




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     G

Gateway – a) An internetworking device that connects two computer
networks that use different communications architectures. b) An IP router.
Many RFC documents use the term gateway rather than router.
Gauge – a) A non-negative integer which may increase or decrease with
a range between 0 and some maximum value. b) A datatype that
measure a quantity that increases and decreases, such as a queue
length.
Get – An SNMP message issued by a manager that requests the status
of a managed object.
GetBulkRequest – A request for a mixture of individual and repeated
(usually tabular) values.
GetNext – An SNMP message issued by a manager, used to walk down
a range of OIDs. The GetNext request retrieves the value of the managed
object one number after the OID listed in the request.
GetNextRequest – a) Fetches the next object in a MIB following a
GetRequest. b) Enables a manager to retrieve values sequentially. One
popular use of the GetNextRequest is to read through the rows of a table.
GetRequest – a) Is a query for the agent running on the managed device
to get and send to the manager one or more specific MIB objects from the
managed device‟s MIB. b) A message that requests the value of one or
more MIB variables.
GetResponse – The agent on the managed device that got GetRequest
or GetNextRequest from the manager software on the managing
computer returns indication of success or failure of any of the
GetRequest, or SetRequest commands.
Group – A named set of closely related MIB definitions within a module.




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       H

Hash Function – a) A function that maps a variable-length data block or
message into a fixed-length value called a hash code. b) The function is
designed in such a way that, when protected, it provides an authenticator
to the data or message. c) Also referred to as a message digest.
Header – System defined control information that precedes user data.
HEMS (High Level Entity Management System) – Generalized version
of HMP.
HMP (Host Monitoring Protocol) – First network management protocol
used in the Internet.




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     I

IAB (Internet Architecture Board) – Board that oversees the Internet        Integer – State values assigned to MIB objects. Objects can have a state
protocol development and standardization process.                           such as, „on‟, „off‟ or „standby‟. Each state can be indicated by an integer
                                                                            value of „1‟, „2‟ or „3‟. Integers are never assigned a value of „0‟.
IANA (Internet Assigned Numbers Authority) – a) Group that assigns
port numbers to functions for Internet applications as described in         Interface – Software and hardware that enables a protocol‟s Network
RFC1700 (or any document that replaces RFC1700). b) IANA defines a          Layer to transmit Protocol Data Units onto a transmission medium. An
hierarchy for naming tables and columns and for deriving numerical          interface may be made up of several sublayers.
object identifiers (OID). IANA assigns identifiers to companies that use
the SNMP protocol.                                                          Intermediate System – See IS.

ICMP (Internet Control Message Protocol) – a) Provides means for            Internet – A collection of communications networks interconnected by
transferring messages between routers and hosts to network                  bridges, routers and/or gateways.
management stations. b) Available on all devices that support IP. c)        Internet Protocol – See IP.
Provides echo/echo-reply to check timing. The recipient of an echo
message is obligated to return the contents of the echo message in an       Internetworking – Communications among devices across multiple
echo-reply message. d) Provides time stamp and time stamp reply, which      networks.
provide a mechanism for sampling the delay characteristics of the           IP (Internet Protocol) – a) A protocol designed for use in an
network. e) Protocol used to report problems in delivering IP datagrams.    interconnected system of packet networks. b) The internet protocol
ICMP also provides several useful query services.                           provides for transmitting blocks of data, called datagrams, from sources
IEEE (Institute of Electrical and Electronic Engineers)                     to destinations, where source and destination are hosts identified by fixed
                                                                            length address. c) The internet protocol also provides for fragmentation
infxsnmp.dll – Library for the Windows version of OnSNMP.                   and reassembly of long datagrams, if necessary, for transmission through
IESG (Internet Engineering Steering Group) – A group that                   small packet networks. d) The network layer datagram protocol of the
coord8inates the activities of the IETF working groups.                     TCP/IP protocol suite. SNMP runs over UCP, which in turn runs over IP.

IETF (Internet Engineering Task Force) – The standards body that            IP Datagram – The unit of data routed by IP.
defines things like SNMP for the Internet.                                  IRTF (Internet Research Task Force) – A group directed by the IAB,
IGP (Interior Gateway Protocol) – Used to exchange routing information      charged with long-term research on Internet protocols.
within an autonomous system.                                                IS (Intermediate System) – a) A device attached to two or more
Implementation – Described in RFC2271 as „an instantiation of a             subnetworks in an internet and that performs routing and relaying of data
subsystem, conforming to one or more specific models.‟                      between end systems. b) Examples of intermediate systems are bridges
                                                                            and routers.
InformRequest – Manager-to-Manager message containing a
notification.                                                               ISO (International Standards Organization) – An international body
                                                                            founded to promote international trade and cooperative progress in
Instance – a) Normally type INTEGER is used to differentiate MIB            science and technology.
objects. b) An instance cannot be assigned to a node, only leaves in the
MIB tree can have instances. c) An object can have more then one            ISODE – Freely available development environment created as a
instance. d) Instances can have instances. For example:                     research tool and represents an effort to promote the use of the ISO
                                                                            interpretation of OSI, particularly in the Internet.
Clothes.footware.shoes.laces.status.2.123.                                  ISP (Internet Service Provider)

The „2‟ indicates the right shoe laces. The „123‟ indicates a particular    ITSP (Internet Telephony Service Providers)
child.                                                                      ITU-T (International Telecommunication Union –
Instrumentation – a) Refers to system dependent program code written        Telecommunications Standardization Sector) – Organization that
by an agent developer, that is used to gather the information that can be   creates recommendations for international voice and data
accessed using SNMP. b) For example the number of packets in and out        communications protocols and regulations.
of an interface must be counted in order that this information can be       IXC (Inter Exchange Carriers) – Entity that provides part of the public
retrieved. c) The instrumentation does the counting.                        network.




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      J




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K




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       L

LAN (Local Area Network) – A network that covers a small geographical
area. Typical LAN technologies include Ethernet and Token-Ring.
Layer – A group of service, functions and protocols that is complete from
a conceptual point of view, that is one out of a set of hierarchically
arranged groups and that extends across all systems that conform to the
network architecture.
LCD (Local Configuration Datastore) – Defined in RFC2275, this is the
place where the SNMP engine stores information about access rights and
policies used by the VACM (View-based Access Control Model).
LEC (Local Exchange Carrier)
LLC (Logical Link Control) – In a local area network, the protocol that
governs the exchange of frames between data stations independently of
how the transmission medium is shared.
LME (Layer Management Entry)
LMI (Layer Management Interface)
LMPE (LAN/MAN Protocol Entity)
LMMS (LAN/MAN Management Service)
Local Configuration Datastore – See LCD.
Logical Link Control – See LLC.




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     M

MAC (Media Access Control) – a) In a local area network, the protocol       Manager – a) Interface between human network manager and device
that governs access to the transmission medium, taking into account the     being managed (an agent). b) The manager also provides the network
topological aspect of the network, to enable the exchange of data           management process. c) Consists of an engine plus a command
between data stations. b) A protocol governing a station‟s access to a      generator and notification receiver application. d) A top-level SNMP
network. For example, CSMA/CD provides a set of MAC rules for sending       master system (hardware or software) serving as the human interface to
and receiving data across a local area network.                             the SNMP network. The manager can issue Get, GetNext and Set
                                                                            requests to agents and receives GetResponse and Trap messages. e)
MAC (Message Authentication Code) – An authenticator that is a              Manager Block Diagram:
cryptographic function of both the data to be authenticated and a secret
key.
Macro – A facility for defining templates that expand the ASN.1 language.
Macro Definitions – Defines the legal macro instance; specifies the
syntax of a set of related types.
Macro Instance – An instance generated from a specific macro definition
by supplying arguments for the parameters in the macro definition;
specifies a particular type.
Macro Instance Value – Represents a specific entity with a specific
value.
MAN (Metropolitan Area Network) – A technology supporting high-
speed networking across a metropolitan area. IEEE 802.6 defines a MAN
protocol.
Managed Component – Hardware or software component that has a               Master Agent – a) In the EMANATE architecture there is one master
corresponding SNMP subagent. To manage a component, an SNMP                 agent that manages one or more subagents. b) The Master Agent
Network Manager communicates with a master agent, and the master            handles the tasks such as: Packet receipt and sending; BER processing;
agent communicates with a subagent.                                         Subagent management such as enrolling and de-enrolling Subagents
                                                                            when they connect and disconnect; Assigns requests to the proper
Managed Objects – Values of network devices that can be read or             Subagent; Authentication; Authorization; Access control and privacy
overwritten by the SNMP manager, like alarm status, control relay status,   functions; Retrieval and write processes; Handles most trap processing.
system uptime. In SNMP terms, every network device is defined in the        c) May have its own MIBs but typically not and is thus MIB independent.
MIB as a set of managed objects.                                            d) As much as possible, the master agent handles the difficult tasks to
Managed Workstation – Workstation that includes a managed                   keep the subagents as simple as possible. e) Program that provides an
component.                                                                  interface between a subagent and an SNMP Network Manager. A
                                                                            managed workstation includes one master agent.
Management Agent – a) Has software (called the „agent‟) that responds
to Management Station queries. b) Can respond asynchronously (with          maxSizeResponseScopedPDU – The maxSizeResponseScopedPDU is
„traps‟) to the Management Station.                                         the maximum size of a scopedPDU to be included in a response
                                                                            message. Note that the size of a scopedPDU does not include the size of
Management Domain – This is a set of resources that share a set of          the SNMP message header.
common management attributes or a set of common resources that share
the same management authority.                                              MAX_OUTPUT_WAITING – a) Sets the maximum number of bytes of
                                                                            communications data the master agent will buffer before it generates an
Management Information Base – See MIB.                                      „overflow‟ condition. b) The default value is 65,536 bytes.
Management Station – a) Shared or standalone computer. b) Has the           MAX_PDU_TIME – a) The maximum amount of time the master agent
following at a minimum: Set of management applications for data             will wait for the subagent to process a request. b) The default value is
analysis, fault recovery; User interface by which the human network         2500 centiseconds (25 seconds).
manager can monitor and control the network; Ability to translate network
manager‟s requirements into the actual monitoring and control of remote     MAX_SUBAGENTS – a) Determines the maximum number of subagents
elements in the network; A database of information extracted from the       that can be connected to the EMANATE master agent at one time. b) The
MIBs of all the managed entities in the network.                            default value is 10.




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SNMP Terms and Acronyms
      Glossary




MAX_THREADS – a) Determines the number of number of SNMP                   Message Processing Subsystem (Preparing Data Elements for an
requests the master agent can service at one time. b) Because the          Incoming SNMP Message) – The Message Processing Subsystem
master agent passes requests to subagents and the subagents can only       provides this service primitive for preparing the abstract data elements
handle one request at a time, in general if there is a small number of     from an incoming SNMP message:
subagents, use a small number. If there is a large number of subagents,
the use a larger number here. The default value is 10.                     result = --                               SUCCESS or errorIndication
                                                                             prepareDataElements(
Medium Access Control – See MAC.                                             IN     transportDomain                  -- origin transport domain
Message Authentication Code – See MAC.                                       IN     transportAddress                 -- origin transport address
                                                                             IN     wholeMsg                         -- as received from the network
Message Level Security – The level consists of authentication,               IN     wholeMsgLength                   -- as received from the network
encryption and timeliness checks.                                            OUT messageProcessingModel              -- typically, SNMP version
Message Processing Model – a) Defined in RFC2271. b) Defines the             OUT securityModel                       -- Security Model to use
format of a particular version of SNMP message and coordinates the           OUT securityName                        -- on behalf of this principal
preparation and extraction of each such version specific message format.     OUT securityLevel                       -- Level of Security requested
                                                                             OUT contextEngineID                     -- data from/at this entity
Message Processing Subsystem – a) Defined in RFC2271. b)                     OUT contextName                         -- data from/in this context
Responsible for preparing messages for sending and extracting data from      OUT pduVersion                          -- the version of the PDU
the received messages. c) It can contain multiple Message Processing         OUT PDU                                 -- SNMP Protocol Data Unit
Models as shown below.                                                       OUT pduType                             -- SNMP PDU type
                                                                             OUT sendPduHandle                       -- handle for matched request
                                                                             OUT maxSizeResponseScopedPDU            -- maximum size of the
                                                                                                                        Response PDU
                                                                            OUT statusInformation                    -- success or errorIndication
                                                                                                                        error counter OID/value if
                                                                                                                        error
                                                                            OUT stateReference                       -- reference to state
                                                                                                                        information to be used for
                                                                                                                        possible Response
                                                                                   )




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                                                                                             SNMP Terms and Acronyms
                                                                                                                                           Glossary




Message Processing Subsystem (Prepare Outgoing SNMP Request or             MF (Mediation Function) – a) Part of the TMN model. b) The MF can
Notification Message) – The Message Processing Subsystem provides          store, adapt, filter, threshold and condense information that is passed
this service primitive for preparing an outgoing SNMP Request or           between the OSF and NEF (or a QAF).
Notification Message:
                                                                           MIB (Management Information Base) – a) A data structure defined by
statusInformation =                  -- success or errorIndication         ASN.1. b) A structure set of data variables, called object, in which each
 prepareOutgoingMessage(                                                   object (data variable) represents some resource to manage. c) Each
 IN      transportDomain             --   transport domain to be used      agent maintains a MIB of network elements that it executes on. d)
 IN      transportAddress            --   transport address to be used     Content of the database is defined by function of the managed object. e)
 IN      messageProcessingModel      --   typically, SNMP version          The content of SNMP is analogous to a dictionary of words. f) Is found in
 IN      securityModel               --   Security Model to use            both the managed object running the agent software and the managing
 IN      securityName                --   on behalf of this principal      computer running the manager software. g) MIB‟s structure will vary
 IN      securityLevel               --   Level of Security requested      depending on the function of the device and the manufacturer. h) A group
 IN      contextEngineID             --   data from/at this entity         of tables that contain the information that a subagent can provide to a
 IN      contextName                 --   data from/in this context        master agent. i) The MIB is a data structure that describes SNMP
 IN      pduVersion                  --   the version of the PDU           network elements as a list of data objects. To monitor SNMP devices,
 IN      PDU                         --   SNMP Protocol Data Unit          your SNMP manager must compile the MIB file for each equipment type
 IN      expectResponse              --   TRUE or FALSE                    in your network.
 IN      sendPduHandle               --   the handle for matching          MIB Family – a) SNMP variables separate into families consisting of the
                                          incoming responses               leafs that come from the same parent node. b) For the purpose of writing
 OUT   destTransportDomain           --   destination transport domain     method routines, SNMP variables are separated into families. A family
 OUT   destTransportAddress          --   destination transport address    consists of all the leaf MIB variables with the same immediate parent
 OUT   outgoingMessage               --   the message to send              node, or root (the Object Identifier without the instance information). For
 OUT   outgoingMessageLength         --   its length                       example, in the MIB II the following variables form a single family since
       )                                                                   they are all children of ifEntry (1.3.6.1.2.1.2.2.1):
Message Processing Subsystem (Prepare Outgoing SNMP Response
Message) – The Message Processing Subsystem provides this service          ifIndex 1.3.6.1.2.1.2.2.1.1
primitive for preparing an outgoing SNMP Response Message:                 ifDescr 1.3.6.1.2.1.2.2.1.2

result =                             -- SUCCESS or FAILURE                 ... skipping entries between…
  prepareResponseMessage(
  IN     messageProcessingModel      --   typically, SNMP version          ifOutQLen 1.3.6.1.2.1.2.2.1.21
  IN     securityModel               --   same as on incoming request      ifSpecific 1.3.6.1.2.1.2.2.1.22
  IN     securityName                --   same as on incoming request      MIB Group – A collection of closely related objects.
  IN     securityLevel               --   same as on incoming request
  IN     contextEngineID             --   data from/at this SNMP entity    MIB II – a) Defined in RFC1213. b) Set of MIB objects to report statistics
  IN     contextName                 --   data from/in this context        about TCP/IP network operations which take place on a particular
  IN     pduVersion                  --   the version of the PDU           system. c) A set of managed object definitions aimed at managing
  IN     PDU                         --   SNMP Protocol Data Unit          TCP/IP-based internets. d) Contains the groups:
  IN     maxSizeResponseScopedPDU    --   maximum size of the
                                          Response PDU
 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
     )
                                                                           MIB Module - Collection of related objects.




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SNMP Terms and Acronyms
      Glossary




MIB Subtree – The set of nodes that are children of a node in the tree of
OBJECT IDENTIFIER.
MIB View – This is an access control identifier that defines the subset of
MIB objects on an SNMP entity which can be managed.
Note that ifNumber (1.3.6.1.2.1.2.1) is also a member of the interface
group, but it is not a member of the same family since it is not a child of
ifEntry.
Model – a) Described in RFC2271 as „a specific design of a subsystem,
defining additional constraints and rules for conformance to the model.‟ b)
A model is sufficiently detailed to make it possible to implement the
specification.
Model-dependent Security ID – a) A model-dependent security ID is the
model-specific representation of a securityName within a particular
Security Model. b) Model-dependent security IDs may or may not be
human readable, and have a model-dependent syntax. c) Examples
include community names, user names and parties. d) The
transformation of model-dependent security IDs into securityNames and
vice versa is the responsibility of the relevant security model.
Module – A named collection of MIB datatype definitions, e.g., for
managing a specific technology such as Ethernet, a specific protocol
family such as Net Ware products protocols, or a specific application such
as electronic mail.
Monitor – A device that listens to all traffic on a LAN, gathering statistics,
and capturing traffic that matches some specific criteria.
Monolithic Agent – a) A compile time extensible SNMP agent. b) In
contrast to a run time extensible agent, a monolithic agent requires that
new MIB objects be incorporated into the agent through recompilation
and re-linking. c) EMANATE Lite is an example of a monolithic agent.
MRTG2 (Multi Router Traffic Gopher) – a) This is a simple tool that
polls OIDs at regular intervals and builds graphical displays of the data.
b) This tools was originally designed for routers but can be used to collect
and display any SNMP OID viewable items.
msnsaagt – a) Command to control the SNMP Research Master Agent.
b) Msnsaagt–stop stops the master agent.
Multi Router Traffic Gopher – See MRTG2.




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                                                                                                 SNMP Terms and Acronyms
                                                                                                                                              Glossary




     N

Naming Identities                                                           Network Interface Types – Used in the Interface (if) section of the MIB.
                                                                            Num             Type                               Description
                                                                              1    other                    None of the following
                                                                              2    regular1822              The original ARPANET interface protocol
                                                                                                            between a host and an Interface Message
                                                                                                            Processor (IMP)
                                                                              3    hdh1822                  A revised version of 1822, using a
                                                                                                            synchronous link scheme
                                                                              4    ddn-x25                  Version of X.25 specified for Defense Data
                                                                                                            Network
                                                                              5    rfc877-x25               Version of X.25 defined in RFC877, intended
                                                                                                            for carrying IP datagrams
                                                                              6    ethernetCsmacd           Ethernet Medium Access Control (MAC)
                                                                                                            protocol
                                                                              7    iso88023Csmacd           IEEE 802.3 CSMA/CD MAC protocol
                                                                              8    iso88024TokenBus         IEEE 802.4 Token Bus MAC protocol
Naming of Management Information – a) Management information                  9    iso88025TokenRing        IEEE 802.5 Token Ring MAC protocol
resides at an SNMP entity where a Command Responder Application has          10    iso88026Man              IEEE 802.6 DQDB MAC protocol for MANs
local access to potentially multiple contexts. b) This application uses a    11    starLan                  A 1Mbps twisted pair version of Ethernet
contextEngineID equal to the snmpEngineID of its associated SNMP             12    proteon-10Mbit           A 10Mbps optical fiber token ring LAN
engine.                                                                                                     developed by Proteon
                                                                             13    proteon-80Mbit           An 80Mbps optical fiber token ring LAN
                                                                             14    hyperchannel             A 50Mbps coaxial cable LAN developed by
                                                                                                            Network Systems
                                                                             15    fddi                     The ANSI Fiber Distributed Data Interface
                                                                                                            (FDDI) standard LAN
                                                                             16    lapb                     The data link control protocol used with X.25
                                                                             17    sdlc                     The data link control protocol used with IBM‟s
                                                                                                            SNA
                                                                             18    dsl                      Interface to a digital transmission line
                                                                                                            operating with the DS-1 format at 1.544Mbps
                                                                             19    el                       A 2.048Mbps conforming to the ITU-T
                                                                                                            specification
                                                                             20    basicISDN                Basic rate ISDN interface, operating at
                                                                                                            192kbps
                                                                             21    primaryISDN              Primary rate ISDN interface, operating at 1.544
                                                                                                            or 2.048Mbps
                                                                             22    propPointToPointSerial   Proprietary serial interface
                                                                             23    ppp                      The Internet Point-to-Point Protocol
                                                                             24    softwareLoopback         Used for transfer between processes in the
                                                                                                            same system
                                                                             25    eon                      The ISO connectionless network protocol
                                                                                                            (CLNP) over IP, referred to as experimental
                                                                                                            OSI-based network, and defined in RFC1406
NEF (Network Element Function) – a) Part of the TMN model. b) The
                                                                             26    ethernet-3Mbit           The original 3Mbps version of Ethernet
NEF provides telecommunications and support functions with the TMN
                                                                             27    nsip                     XNS over IP
that are required by the network that is being managed.                      28    slip                     The Internet standard Serial Line Interface
net start snmp – Command that starts SNMP Research Master Agent on                                          Protocol
the PQM300.                                                                  29    ultra                    A high-speed fiber interface developed by Ultra
                                                                                                            Network Technologies
net stop snmp – Command that stops SNMP Research Master Agent on             30    ds3                      Interface to a digital transmission line
the PQM300.                                                                                                 operating with the DS-3 format at 44.736Mbps
                                                                             31    sip                      Transmission of IP datagrams over a SMDS
                                                                                                            metropolitan-area network
                                                                             32    frame-relay              Frame relay network interface




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SNMP Terms and Acronyms
      Glossary




 33     rs232                    RS232, now EIA232D interface                   NTCS (Network Technical Control System) – A system consisting of
 34     para                     Parallel port interface                        hardware probes and supporting software that deals with fault detection,
 35     arcnet                   ARCnet LAN                                     fault isolation and fault recovery.
 36     arcnetPlus               ARCnet Plus LAN
 37     atm                      Asynchronous transfer-mode network interface   NVT ASCII (Network Virtual Terminal ASCII) – a) A subset of ASCII
 38     miox25                   Multiprotocol interconnect on X.25 and ISDN    code defined by RFC-854 for use with the telnet protocol. b) NVT ASCII.
 39     sonet                    The synchronous optical network (SONET)        consists of printable ASCII characters and selected control characters
                                 and SDH high-speed optical network interface   such as carriage-return.
 40     x25ple                   X.25 packet-level entity
 41     iso880211c               Logical link control, defined in IEEE 802.2
 42     localTalk                Old Apple network interface specification
 43     smdsDxi                  SMDS data exchange interface
 44     frameRelayService        Frame relay network-side interface
 45     v35                      V.35 ITU-T specification
 46     hssi                     High-speed serial interface
 47     hippi                    High performance parallel interface
 48     modem                    Generic modem
 49     aal5                     ATM adaptation layer 5, providing a simple
                                 service interface to ATM
 50     sonetPath                SONET path
 51     sonetVT                  SONET virtual tributary
 52     smdsIcip                 SMDS intercarrier interface
 53     propVirtual              Proprietary virtual/internal
 54     propMultiplexor          Proprietary multiplexing

Network Layer – a) Third layer of the OSI network management model.
b) Provides communications functions for an internetwork including global
addressing (IP level addressing) routing and switching that takes data
from its source to its destination via an internetwork of LANs, MANs and
WANs.
Network Management Software – see NMS.
Network Management Station – See NMS.
Network Monitoring System – See NMS.
Network Technical Control System – See NTCS.
NMA (Network Management Application)
NME (Network Management Entity)
NMP (Network Management Protocol) – Protocol of SNMP.
NMS (Network Management Software) – Another term for SNMP
manager software or hardware.
NMS (Network Management Station) – a) In the context of SNMP, a
software module that executes management applications that monitor
and control network elements, such as hosts, bridges and routers. b) A
network management station communicates with an agent in a network
elements by means of SNMP.
NMS (Network Monitoring System) – An integrated set of hardware and
software that measures and analyzes communications related
parameters in a network.
Node – a) MIB branch point where one or more items (either more nodes
or objects) appear. b) A node cannot be assigned an instance. c)
Endpoint of a network connection or a junction common to two or more
lines in a network.



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                                                                               SNMP Terms and Acronyms
                                                                                                               Glossary




     O

Object – Instrumentation item in the MIB that can be monitored or set.
Object Identifier – See OID.
Object Instance – A specific instance of an object type that has been
bound to a specific value.
Object Type – a) Defines a particular kind of managed object. b) The
definition of an object type is therefore a syntactic description.
Octet – A group of eight bits, usually operated upon as an entity.
OID (Object Identifier) – a) Describes the unique MIB path from the MIB
(instrument parameter to monitor called an object) root to a specific
instrument parameter. b) Tektronix‟ OID path is: 1.3.6.1.128. c) The path
to Tektronix TVT is: 1.3.6.1.128.5. d) The path to Tektronix TVT products
is: 1.3.6.1.128.5.1. e) The path to Tektronix PQM is: 1.3.6.1.128.5.1.5. f)
a numerical value that identifies an MIB, an MIB table, a parameter
(column) in an MIB table, or an object (row) in an MIB table. g) A string of
numbers derived from a global naming tree, used to identify an object.
One Way Function – A function that is easily computed, but the
calculation of its inverse is infeasible.
Open System Interconnect (OSI) Reference Mode – a) A model of
communications between cooperating devices. b) It defines a seven layer
architecture of communications functions.
onsnmp – Subagent program for the UNIX version of OnSNMP.
onsnmp.exe – Subagent program for the Windows version of OnSNMP.
OnSNMP – Subagent for an Informix database server or coserver. On
UNIX, OnSNMP consists of onsnmp. In Windows, OnSNMP consists of
onsnmp.exe, infxsnmp,dll and onsrvapd, exe.
onsrvapd – Server discovery program for the UNIX version of OnSNMP.
onsrvpd.exe – Server discovery program for the Windows version of
OnSNMP.
OSF (Operations Systems Function) – a) Part of the TMN model. b)
Processes information related to the telecommunications management
functions that monitor, coordinate and control telecommunications
activities.
OSI (Open System Interconnect)




                                                                                       www.tektronix.com/video_audio   21
SNMP Terms and Acronyms
      Glossary




       P

Packet – a) A group of bits that includes data plus control information. b)    PDU Dispatcher (Generate Outgoing Response) – The PDU
Generally refers to a network layer (OSI layer 3) protocol data unit. c)       Dispatcher provides the following primitive for an application to return an
Originally, a unit of data sent across a packet switching network.             SNMP Response PDU to the PDU Dispatcher:
Currently, the term may refer to a protocol data unit at any layer.
                                                                               returnResponsePdu(
Packet Internet Groper - See PING.                                               IN    messageProcessingModel            -- typically, SNMP version
Packet Switching – a) A method of transmitting messages through a                IN    securityModel                     -- Security Model in use
communications network, in which long messages are subdivided into               IN     securityName                     -- on behalf of this principal
short packets. b) Each packet is passed from source to destination               IN    securityLevel                     -- same as on incoming request
through intermediate nodes. c) At each node, the entire message is               IN    contextEngineID                   -- data from/at this SNMP entity
received, stored briefly and then passed on to the next node.                    IN    contextName                       -- data from/in this context
                                                                                 IN    pduVersion                        -- the version of the PDU
Party Based SNMPv2 – a) SNMP version 2. b) A historic protocol                   IN    PDU                               -- SNMP Protocol Data Unit
defined by RFC1441 through RFC1452.                                              IN    maxSizeResponseScopedPDU          --  maximum size of the
PDU (Protocol Data Unit) – a) Building block of SNMP messages. b) A                                                         Response PDU
set of data specified in a protocol of a given layer and consisting of          IN     stateReference                    -- reference to state information
protocol control information of that layer, and possibly user data of that                                                  as presented with the request
layer. c) An example is the SNMP GetRequest command request data                IN     statusInformation                 -- success or errorIndication
from a managed object. The managed object responds with data in the                                                         error counter OID/value if
form of a PDU. d) A generic term for protocol unit (e.g. a header) used at                                                  error
any layer.                                                                             )

PDU Dispatcher (Generate Outgoing Request or Notification) – The               PDU Dispatcher (Process Incoming Response PDU) – The PDU
PDU Dispatcher provides the following primitive for an application to send     Dispatcher provides the following primitive to pass an incoming SNMP
an SNMP Request or Notification to another SNMP entity:                        Response PDU to an application:

statusInformation =                       -- sendPduHandle if success          processResponsePdu(                       --   process Response PDU
                                             errorIndication if failure         IN    messageProcessingModel             --   typically, SNMP version
sendPdu(                                                                        IN    securityModel                      --   Security Model in use
 IN    transportDomain                    --   transport domain to be used      IN    securityName                       --   on behalf of this principal
 IN     transportAddress                  --    transport address to be used    IN    securityLevel                      --   Level of Security
 IN    messageProcessingModel             --   typically, SNMP version          IN    contextEngineID                    --   data from/at this SNMP entity
 IN    securityModel                      --   Security Model to use            IN    contextName                        --   data from/in this context
 IN    securityName                       --   on behalf of this principal      IN    pduVersion                         --   the version of the PDU
 IN    securityLevel                      --   Level of Security requested      IN    PDU                                --   SNMP Protocol Data Unit
 IN    contextEngineID                    --   data from/at this entity         IN    statusInformation                  --   success or errorIndication
 IN    contextName                        --   data from/in this context        IN    sendPduHandle                      --   handle from sendPdu
 IN    pduVersion                         --   the version of the PDU                 )
 IN    PDU                                --   SNMP Protocol Data Unit
 IN    expectResponse                     --   TRUE or FALSE
       )




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                                                                                                   SNMP Terms and Acronyms
                                                                                                                                                 Glossary




PDU Dispatcher (Process Incoming Request or Notification PDU) –                  Privacy – Protection of the contents of a message by means of
The PDU Dispatcher provides the following primitive to pass an incoming          encryption.
SNMP PDU to an application:
                                                                                 Private Key – A secret key used for authentication or encryption.
processPdu(                      -- process Request/Notification                 Probe – In the context of RMON, a remote network monitor.
                                    PDU
 IN     messageProcessingModel   -- typically, SNMP version                      Propagation Delay – The delay between the time a signal enters a
 IN     securityModel            -- Security Model in use                        channel and the time it is received.
 IN     securityName             -- on behalf of this principal                  Protocol – A set of semantic and syntactic rules that determines the
 IN     securityLevel            -- Level of Security                            behavior of entities in the same layer in performing communication
 IN     contextEngineID          -- data from/at this SNMP entity                functions.
 IN     contextName              -- data from/in this context
 IN     pduVersion               -- the version of the PDU                       Protocol Control Information – Information exchanged between entities
 IN     PDU                      -- SNMP Protocol Data Unit                      of a given layer, via the service provided by the next layer, to coordinate
 IN     maxSizeResponseScopedPDU -- maximum size of the                          their joint operations.
                                    Response PDU
                                                                                 Protocol Data Unit – See PDU.
 IN     stateReference           -- reference to state information
                                    needed when sending a                        Protocol Operations – a) Defines the rules which govern how messages
                                    response                                     are exchanged between SNMP entities (managers and agents) including
        )                                                                        format of the messages as well as the expected dialogue sequence. b)
                                                                                 For example, the protocol operations define the shape of a Set request
Performance Management – a) One of the file OSI systems
                                                                                 packet and define that the correct response to a Set request is a
management functional areas (SMFAs). b) Consists of facilities needed
                                                                                 GetResponse.
to evaluate the behavior of managed objects and the effectiveness of
communication activities.                                                        Proxy – a) In the context of SNMP, an agent (the proxy agent) that acts
                                                                                 on behalf of another network element (the proxied device). b) A
Permanent Virtual Circuit (PVC) – The packet switched network
                                                                                 management station sends queries concerning a device to its proxy
equivalent of a leased line.
                                                                                 agent. c) The proxy agent is responsible for collecting the information or
Physical Layer – a) First layer of the OSI network management model.             triggering the action requested of the proxied device by the management
b) Provides physical transmission medium for carrying the raw data such          station.
as electrical signals or optical impulses from network node to the next.
                                                                                 Proxy Agent – An SNMP agent that translates non-SNMP messages
PING – Packet Internet Groper                                                    and inputs to SNMP. In network alarm monitoring, a proxy agent is
                                                                                 usually an RTU that converts contact closure inputs to SNMP traps, like
Plain Text – The input to an encryption function or the output of a              the NetGuardian 832A. Devices that mediate other alarms in other
decryption function.                                                             protocols to SNMP, like the NetMediator T2S (TBOS to SNMP) is also a
Point-to-Point Protocol (PPP) – A protocol for data transfer across              proxy agent.
serial links. PPP supports extensive link configuration capabilities, and        Proxy Forwarder – a) Forwards proxy messages. b) Implementation of a
allows traffic for several protocols to be multiplexed across the link.          proxy forwarder is optional.
Presentation Layer – a) Layer 6 of the OSI model. b) Provides for the
selection of a common syntax for representing data and for
transformation of application data into and from the common syntax. c)
Represents application data so that it can be properly interpreted at the
destination by performing functions such as data
compression/decompression, encryption or ASCII to EBCDIC code
conversion.
Primitive Type (ASN.1) – A basic datatype such as an INTEGER or
OCTET STRING.
Principle – a) A principle is the „who‟ on whose behalf services are
provided or processing takes place. b) A principle can be, among other
things, an individual acting in a particular role; a set of individuals, with
each acting in a particular role; an application or a set of applications; and
combinations thereof.




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SNMP Terms and Acronyms
      Glossary




       Q

QAF (Q Adapter Function) – a) Part of the TMN model. b) The QAF is
used to translate, and to connect into the TMN, non-TMN functions.




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                                                                                                  SNMP Terms and Acronyms
                                                                                                                                                  Glossary




     R

Registering Responsibility for Handling SNMP PDUs – Applications               RFC1212 – Concise MIB definitions.
can register/unregister responsibility for a specific contextEngineID, for
specific pduTypes, with the PDU Dispatcher according to the following          RFC1213 – a) Management Information Base for Network Management
primitives. The list of particular pduTypes that an application can register   of TCP/IP Based Internets: MIB-II. b) Describes the managed objects
for is determined by the Message Processing Model(s) supported by the          contained in the MIB.
SNMP entity that contains the PDU Dispatcher.                                  RMON (Remote Network Monitoring) – a) An extension to SNMP that
                                                                               allows for the monitoring of the subnetworks as a whole rather than just
statusInformation =                  -- success or errorIndication             individual devices. b) A device that collects information about network
registerContextEngineID(                                                       traffic.
  IN     contextEngineID             -- take responsibility for this one
  IN     pduType                     -- the pduType(s) to be registered        RMON MIB (Remote Network Monitoring MIB) – A MIB that enables a
         )                                                                     manager to configure a monitor to report statistics, history, host activities,
unregisterContextEngineID(                                                     and events and initiate or end packet capture.
  IN     contextEngineID             -- give up responsibility for this one    Router – a) An internetworking device that connects two or more
  IN     pduType                     -- the pduType(s) to be unregistered      computer networks. b) It makes use of an internet protocol and assumes
         )                                                                     that all of the attached devices on the network use the same
                                                                               communications architecture and protocols. c) A router operates at OSI
Note that realizations of the registerContextEngineID and                      layer 3, the IP layer.
unregisterContextEngineID abstract service interfaces may provide
implementation-specific ways for applications to register/deregister           Routing – The determination of a path that a data unit (name, packet,
responsibility for all possible values of the contextEngineID or pduType       message) will transverse from source to destination.
parameters.
                                                                               Routing Tables – Table stored in a router or some other internetworking
Remote Network Monitor – a) An agent, implemented in a network                 device that keeps track of routes to particular network destinations and, in
element, that observes all of the traffic on the network or networks and       some cases, metrics (method by which a routing algorithm determines
maintains information and statistics concerning that traffic in its MIB. b)    that one route is better than another) associated with those routes.
Also referred to as a probe.
                                                                               RPC (Remote Procedure Call)
Requests – a) GetRequest – Is a query for one or more specific MIB
                                                                               runsnmp.ksh – Helper script to ensure that both the onsrvapd server
objects. b) GetNextRequest – Fetches the next object in a MIB following
                                                                               discovery daemon and the SNMP master agent are running on a host.
a GetRequest. c) SetRequest – Sets a MIB object value that maybe used
to control the action of the instrument. d) GetResponse – Returns
indication of success or failure of any of the GetRequest,
GetNextRequest or SetRequest commands.
Response – A message responding to a GetRequest, GetNextRequest,
GetBulkRequest, SetRequest or InformRequest.
Response Time – In a data system, the elapsed time between the end of
transmission of an inquiry message and the beginning of the receipt of a
response message, measured at the inquiry terminal.
RFC (Request for Comments) – a) Documents maintained by the IETF
standards body containing standards in various stages of completion. b)
A set of documents containing Internet protocols and discussions of
related topics. These documents are available online at the Network
Information center.
RFC1155 – a) Structure and Identification of Management Information for
TCP/IP Based Internets. b) Defines how managed objects contained in
the MIB are defined.
RFC1157 – a) Simple Network Management Protocol. b) Describes
Abstract Syntax Notation (ASN.1).




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SNMP Terms and Acronyms
      Glossary




       S

SAP (Service Access Point) – a) A means of identifying a user of the               Security Subsystem – a) Defined in RFC2271. b) Provides security
services of a protocol entity. b) A protocol entity provides one or more           services such as the authentication and privacy of messages and
SAPs, for use by higher level entities.                                            potentially contains multiple Security Models as shown in the following
                                                                                   figure.
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.
Security Administration Framework – a) Defines mechanisms which
control the level of service provided by an SNMP entity. b) The                    Security Subsystem (Generate Request or Notification Message) –
mechanisms discriminate each message based on who is sending the                   The Security Subsystem provides the following primitive to generate a
message, what operation is requested, where the operation takes place              Request or Notification message:
within the MIB and how the request is being sent (security protocol in
use). c) To specify a level of service in an SNMP entity, we need to have          statusInformation =
a authentication identifier, authorization identifier, access control identifier   generateRequestMsg(
and security identifier. d) Elements of security include:                           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
Security Management – a) One of the five OSI systems management
                                                                                            )
functional areas (SMFAs). b) Addresses those aspects of OSI security
essential to operate OSI network management correctly and to protect               Security Subsystem (Generate Response Message) – The Security
managed objects.                                                                   Subsystem provides the following primitive to generate a Response
                                                                                   message:
Security MIB – Each security model defines the MIB module(s) required
for security processing, including any MIB module(s) required for the
                                                                                   statusInformation =
security protocols(s) supported. The MIB module(s) should be defined
                                                                                   generateResponseMsg(
concurrently with the procedures which use the MIB module(s). The MIB
                                                                                    IN      messageProcessingModel     -- typically, SNMP version
modules(s) are subject to normal access control rules.
                                                                                    IN      globalData                 -- message header, admin data
Security Model – a) Defined in RFC2271. b) Defines threats against                  IN      maxMessageSize             -- of the sending SNMP entity
which it protects, the goals of the security service and the security               IN      securityModel              -- for the outgoing message
protocols used to provide security such as authentication and privacy.              IN      securityEngineID           -- authoritative SNMP entity
                                                                                    IN      securityName               -- on behalf of this principal
Security Protocol – a) Defined in RFC2271. b) Defines the mechanisms,               IN      securityLevel              -- for the outgoing message
procedures and MIB data used to provide security services such as                   IN      scopedPDU                  -- message (plaintext) payload
authentication.                                                                     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
                                                                                        )




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                                                                                                   SNMP Terms and Acronyms
                                                                                                                                                 Glossary




Security Subsystem (Process Incoming Message) – The Security                     SGMP (Simple Gateway Monitoring Protocol) – a) Introduced in 1987
Subsystem provides the following primitive to process an incoming                as a simple means of monitoring gateways. b) A predecessor of SNMP.
message:
                                                                                 SMAE (System Management Application Entry)
statusInformation =                       -- errorIndication or success          SMAP (System Management Application Process)
                                             error counter OID/value if
                                             error                               SMF (System Management Functions) – A part of the OSI systems
processIncomingMsg(                                                              management activities which satisfy a set of logically related user
 IN     messageProcessingModel            --   typically, SNMP version           requirements.
 IN     maxMessageSize                    --   of the sending SNMP entity        SMFA (System Management Functional Areas) – Fault Management,
 IN     securityParameters                --   for the received message          Account Management, Configuration Management, Performance
 IN     securityModel                     --   for the received message          Management, and Security Management.
 IN     securityLevel                     --   Level of Security
 IN     wholeMsg                          --   as received on the wire           SMI (Structure of Management Information) – a) Grammar for SNMP.
 IN     wholeMsgLength                    --   length as received on the         b) Is the logical organization of the data in the MIB. c) Has hierarchical
                                               wire                              tree structure in which objects are organized into conceptual trees. d)
 OUT    securityEngineID                  --   identification of the principal   Defines generic data types for objects such as; INTEGER, OCTET
 OUT    securityName                      --   identification of the principal   STRING. e) Defines the rules for creating new MIB objects and writing
 OUT    scopedPDU,                        --   message (plaintext) payload       MIBs. f) Each object must have the following: Name (Object Identifier –
 OUT    maxSizeResponseScopedPDU          --   maximum size of the               OID; Syntax (data type – string of octets or integer); An „encoding‟ –
                                               Response PDU                      description of how information describing managed objects is serialized
 OUT securityStateReference               --   reference to security state       for transmission between machines. g) Defines the common interface
                                               information, needed for           definition language.
                                               response
                                                                                 SMP (Simple Management Protocol)
        )
                                                                                 SNMP (Simple Network Management Protocol) – a) Common
securityLevel – a) This architecture recognizes three levels of security:
                                                                                 language for control of instruments over a network. b) First introduced in
without authentication and without privacy (noAuthNoPriv); with
                                                                                 1988. c) The specification for this full standard is published in RFC1155,
authentication but without privacy (authNoPriv); with authentication and
                                                                                 RFC1157 and RFC1212.
with privacy (authPriv). b) These three values are ordered such that
noAuthNoPriv is less than authNoPriv and authNoPriv is less than                 SNMP Agent – An SNMP entity containing one or more command
authPriv. Every message has an associated securityLevel. All                     responder and/or notification originator applications (along with their
Subsystems (Message Processing, Security, Access Control) and                    associated SNMP engine) has traditionally been called an SNMP agent.
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.
securityName – A securityName is a human readable string representing
a principle. It has a model independent format and can be used outside a
particular Security Model.
Sequence – ASN.1 type for definition of simple two-dimensional table
with scalar-valued entries.
Server Discovery Process – The discovery process discovers multiple
server instances running on the host. These instances might belong to
different versions that are installed on different directories.
Service Access Point – See SAP.
Session Layer – a) Fifth layer of the OSI managed network layers. b)
                                                                                 snmpd.cnf – a) Special file for SNMP Research EMANATE product. b)
Establishes a logical connection between end user applications by
                                                                                 This file contains MIB II system and snmp group information and consists
including mechanisms that synchronize the data transfer once a
                                                                                 of at least the following items: sysDescr, sysObjectID, sysLocation,
connection is established.
                                                                                 sysContacts, and sysName. c) Is read by the master agent on startup to
SetRequest – Sets a MIB object value that maybe used to control the              get data on how to behave under various conditions. d) Consists of the
action of the instrument.                                                        following entries: MAX_THREADS and MAX_PDU_TIME.




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snmpdm – a) DOS command to control the SNMP Research EMANATE                  SNMPv1 (SNMP Version 1) – a) Industry defacto standard and is widely
Master Agent. b) snmpdm–stop stops the SNMP Research Master Agent.            supported. b) First introduced in 1988 and became a full standard in 1990
c) snmpdm–start starts the SNMP Research Master Agent.                        as described in RFC1155, 1157 and 1212. c) „Community Model‟
                                                                              Security:
SNMP Entity – a) Implementation of the architecture as defined in
RFC2271. b) Consists of an SNMP engine and one or more associated
applications.
SNMP Engine – a) As defined in RFC2271, it provides service for
sending and receiving messages, authenticating and encrypting
messages, and controlling access to managed objects. b) There is a one-
to-one association between an SNMP engine and the SNMP entity which
contains it. c) The engine contains: Dispatcher, Message processing
subsystem, Security subsystem and Access control subsystem.                   SNMPv2 (Party Based) – a) Defined in RFC1902-1907. b) Superset of
                                                                              SNMPv1 to which was added: Enhanced authentication and security;
snmpEngineID – a) Within the administrative domain, an snmpEngineID           Competing versions of SNMPv2 were proposed without final resolution on
is the unique and unambiguous identifier of an SNMP engine. b) Since          a single SNMPv2 standard. c) Was not widely implemented because of
there is a one-to-one association between SNMP engines and SNMP               difficulty in setting up security, amount of system resources required for
entities, it is also uniquely and unambiguously identifies the SNMP entity.   agent, little vendor support and instability. d) Security Implementation:
snmpinfo.dat – a) SNMP Research specific file needed by SNMP                  Improved over SNMPv1. e) Has no message definition.
manager. b) This file is not read by the Master Agent or subagents on a       SNMPv2c (Community Model) – a) Defined by RFC1901. b) Has
managed device. c) This file is read by the SNMP Research manager. d)         message format similar to SNMPv1. c) Community name based
It contains English name to OID (dotted decimal notation) conversions for     securitySNMPv2 that combined SNMPv2 functionality with SNMPv1 trivial
objects. e) This file is also used by the manager to parse command line       authentication that was introduced in 1996. d) Is an SNMPv2 payload
arguments. f) If this file does not contain translation information for an    inside of SNMPv1 wrapper. Some call this version, SNMPv1.5.
agent MIB object, then an error message is printed by the getmany
command such as: Cannot translate MIB variable: svSvcName                     SNMPv2u (User Model) – a) Attempt to fix security problems of the party
                                                                              based SNMPv2. b) Was beat out by SNMPv2c and thus never widely
SNMP Network Manager – Program that monitors and controls managed             implemented.
components on a network.
                                                                              SNMPv2* - a) Simple Network Management Protocol version 2 „star‟. b) A
SNMP Manager – a) Defined in RFC2271. b) Contains one or more                 proposed protocol (published as Internet Drafts) which provides an
command generators and/or notification receiver applications (along with      administrative framework (authorization, access control) and a remote
their associated SNMP engines) as shown below:                                configuration/remote administration MIB. c) SNMPv2* builds on the
                                                                              foundation provided by SNMPv1, SNMPv2u, SNMPv2c and the SNMPv2
                                                                              draft standard in RFC1902-1908. d) The „star‟ is a wildcarding asterisk
                                                                              signifying that this protocol adopted many of the best ideas from the
                                                                              SNMPv2 proposals which preceded it.
                                                                              SNMPv3 – a) Introduced in 1997. b) IETF is working on SNMPv3 to fix
                                                                              the mess left by the SNMPv2. c) The specifications for this proposed
                                                                              standard are published in RFC2271-2275. d) SNMPv3 provides a
                                                                              Proposed Standard administrative framework (authorization, access
                                                                              control, etc…) and remote configuration/remote administration MIB. e)
                                                                              Added these new features: New data type – Counter64; New operator –
                                                                              GetBulk; Confirmed event delivery – Inform requests; Improved Sets
                                                                              include Rich error codes, Exceptions and RowStatus TEXTUAL-
                                                                              CONVENTIONS; Transport independence; Changes to Traps; Report
                                                                              PDU to eliminate silent denial of service; Access Control; Security for
                                                                              messages; New SNMP message format. f) Has very modular design so it
                                                                              can incorporate new technologies more easily such as public key
                                                                              cryptography.
                                                                              Socket – a) An IP address appended to a port number that allows two IP
                                                                              devices to communicate. b) Stream Sockets are used with TCP to
                                                                              provide reliable, sequential, bi-directional exchange of data. c) Datagram




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Sockets are used with UDP to provide unreliable, bi-directional data            sysLocation – a) Required entry in MIB II snmpd.cnf file. b) Physical
transfer.                                                                       location of managed object as string text which is called an octetString.
Software Monitor – A software module resident in main memory on a               sysName – a) Required entry in MIB II snmpd.cnf file. b) This is the
host or communications processor that can gather and report statistics on       domain name of managed object as string text which is called an
configuration, communications and software activity.                            octetString.
Standing Alarm List – A list of all uncleared alarms, as maintained by a        sysObjectID – a) Required entry in MIB II snmpd.cnf file. b) Vendor‟s
full-featured network alarm management system. Standard SNMP                    authoritative identification of the network management subsystem
managers automatically delete all acknowledged traps, but a standing            contained in the entity and is given as a dotted decimal notation. c) The
alarm list displays every alarm that has not been reported as cleared by        dotted decimal notation is allocated within the SMI enterprises sub-tree
the monitoring equipment.                                                       and provides an easy and unambiguous means for determining what kind
                                                                                of system is being managed.
State – a) Objects can have a state such as, „on‟, „off‟ or „standby‟. b)
Each state can be indicated by an integer value of 1, 2 or 3.                   System Management Functions – See SMF
State Reference Information (Releasing Memory Primitive) – All                  System Management Functional Areas – See SMFA
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
        )
Static Subagent – a) On architectures that support shared libraries, the
EMANATE master agent can load a shared library subagent directly into
its process space at startup time. b) When the master agent loads a
shared library subagent at startup time, it becomes a functional part of the
master agent and cannot be unloaded at a later point of execution. c)
Also called Shared Library Subagent.
Station – Any node on a LAN that participates in the LAN‟s Media
Access Control protocol.
subagent – a) This definition is as the term applies to the EMANATE
model. b) A Subagent normally implements a single MIB file and is
responsible for collecting or calculating the values of a MIB variable and
passing that information to the Master Agent for sending to the requesting
manager. c) Messages are passed asynchronously between the Master
Agent and Subagents. d) Subagents can be started in any order. e)
Normally handle the simpler tasks while the Master Agent does the more
difficult tasks. f) Program that lets a managed component and a master
agent communicate with each other.
subnetwork – a) Refers to a constituent network of an internet. b) This
avoids ambiguity since the entire internet, from a user‟s point of view, is a
single network.
subsystem – Is defined in RFC2271 as „an abstract and incomplete
specification of a portion of a framework that is further refined by a model
(refer to the definition of „model‟ in this glossary) specification.
sysContact – a) Required entry in MIB II snmpd.cnf file. b) Name of
person to contact for the managed object and how to contact the person
as string text which is called an octetString.
sysDescr – a) Required entry in MIB II snmpd.cnf file. b) Name of
managed object as string text which is called an octetString.




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SNMP Terms and Acronyms
      Glossary




       T

Table – a) A different conceptual representation of instances of objects at
the leaves. b) A logical structuring of MIB variables into rows and
columns.
TCP (Transmission Control Protocol) – a) Connection oriented, end to
end, transport layer protocol. b) Achieves reliability through
retransmission. c) The more common transport layer protocol lin the
TCP/IP suite. TCP is considered a “reliable” protocol because it
establishes a connection between the host and the recipient,
guaranteeing delivery. UDP, the transport protocol used for SNMP does
not establish a connection or guarantee delivery.
TCP/IP Information – IP address to physical address translation,
incoming and outgoing IP datagram counts, tabulation of TCP.
TFTP (Trivial File Transfer Protocol)
TLV (Type, Length, Value) – This is another name for the data string
created by the BER.
TMN (Telecommunication Management Network) – Defined by the
ITU-T M.3010.
Token-Ring – A local area network technology based on a ring topology.
Stations on the ring pass a special message, called a token, around the
ring. The current token holder has the right to transmit data for a limited
period of time.
Transport Layer – a) Layer four of the OSI model. b) Provides reliable,
sequenced transfer of data between end points. c) This is the layer in
which TCP or UDP are used.
Trap – a) In the context of SNMP, an unsolicited message sent by an
agent to a management station. b) The purpose of a trap is to notify the
management station of some unusual event.
TrapRcv (Trap Receive) – Permits monitoring of SNMP trap responses
on the PC screen.
TrapSend – Demonstrates how to send trap messages to trap monitoring
stations.
Transport Layer – a) Fourth layer of the OSI model for managed
networks. b) Assures reliable end to end delivery of data if using TCP by
ensuring error control and proper packet sequencing among other things.
TSAP (Transport Service Access Point)
Types (Data Types)




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                                                                           SNMP Terms and Acronyms
                                                                                                           Glossary




     U

UDP (User Datagram Protocol) – a) Connectionless, end-to-end
transport layer protocol. b) SNMP is based on UDP rather than TCP. c)
The transport layer protocol used to send SNMP messages. Unlike TCP,
UDP is a connectionless protocol that does not guarantee delivery of the
data packet. However, UDP uses fewer network resources than TCP,
making it more suitable for transporting a large number of status
messages.
USM (User-based Security Model)




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SNMP Terms and Acronyms
      Glossary




       V

V1 MIB – a) MIBs written based on RFC1212 and RFC1215. b) Is
protocol independent, that is, it can be accessed by SNMPv1, SNMPv2 or
SNMPv3 based managers or agents. c) This version of MIB can be read
by software that only supports MIBs written based on Concise MIB
Definition rules.
V2 MIB – a) Latest guide lines for writing MIBs based on V2 SMI. b) All
new MIBs should be written following these guide lines and are called V2
MIBs. c) Is protocol independent, that is, it can be accessed by SNMPv1,
SNMPv2 or SNMPv3 based managers or agents. d) Some older, third
party software can only access MIBs written following the Concise MIB
Definitions. If we have a V2 MIB, we can convert it to a V1 MIB which can
then be read by this older software.
V2 SMI – a) Improvement on (V1) SMI. b) V2 MIBs result from V2 SMI.
VACM (View-based Access Control Model) – This model controls MIB
access.
VarBind – a) An SNMP variable binding such as an OID and a value. b)
Includes an OID and a value (the value can be null).
Variable Binding – The data field of a GetResponse or Trap PDU. Each
variable binding lists a managed object and its current value.
View-based Access Control Model – See VACM.
Virtual Circuit – a) A packet switching mechanism in which a logical
connection (virtual circuit) is established between two stations at the start
of transmission. b) All packets follow the same route, need not carry a
complete address and arrive in sequence. c) A term derived from packet
switching networks. A virtual circuit is supported by facilities which are
shared between many users, although each circuit appears to its users as
dedicated end-to-end connection.
VPN (Virtual Private Network)




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                                                                                                          Glossary




     W

WAN (Wide Area Network) – A network that covers a large geographical
area. Typically WAN technologies include point-to-point, X.25 and frame
relay.
WSF (Work Station Function) – a) Part of the TMN model. b) The WSF
provides a way for the human network manager to interpret management
information.




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SNMP Terms and Acronyms
      Glossary




       X

X.25 – A CCITT standard for connecting computers to a network that
provides reliable, virtual-circuit-based data transmission.




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    SNMP Terms and Acronyms
                                    Glossary




Y




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SNMP Terms and Acronyms
     Glossary




      Z




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