Management Information Base

8/3/2019 Management Information Base

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Management Information Base

(MIB)


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Management Information Base (MIB)

The MIB can be thought of as a virtual information store, holding

managed objects wh

ose values collectively reflect th

e current state ofthe network

Managed objects are specified using the OBJECT-TYPE SMI construct

and gathered into MIB modules using the MODULE-IDENTITY

construct as just discussed.


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The MIB contains the

name object identifier (a numeric value)

data type and indication of whether the value associated

with the object can be read from and/or written to


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MIB

Each managed object in a MIB has a unique identifier.

The identifier includes

the object's type

(such as counter, string, gauge, or address)

the object's access level

(such as read or read/write)

size restrictions and

range information.


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SNMP


Structure of Management Information.

MIB Object Definition.


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MIB(Management Information Base)

Each resource to be managed is represented by an object. Collections

of these objects is MIB.

Each object is a data variable that represents one aspect of the

managed agent. e.g.: these aspects may be the TCP,IP,UDP

connections done .

MIB is a text file that describes the managed object using syntax of

ASN.1(Abstract Syntax Notation).


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STRUCTURE OF MANAGEMENT INFORMATION

SMI generates a framework within which

a MIB can be defined and constructed.

SMI identifies the data types used in MIB and specifies how resourceswithin the MIB can be represented and named.

Defines individual object including the syntax and the value of the object.


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Data Types:

1.SIMPLE TYPES:

2.APPLICATION-WIDE TYPES:

INTEGER

OBJECT STRING

OBJECT IDENTIFIER

Gauge

Counter

Time Ticks IP Address

Opaque

Network Address

Structure Of Management Information


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MIB Structure

Each Type of object is associated with an

identifier called Object Identifier(OID).

Identifier serves to name the object and also a

value is associated with the type of the object.

An OID is represented by a sequence of integers

separated by decimal points.

Set of defined objects has a Tree

Structure.


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MIB Object Group

iso(1)

org(3)

dod(6)

internet(1)

directory(1)

private(4)

mgmt(2)

experimental(3)


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MIB Object Group Condt

mgmt (2) mib-2(1)

system (1)

snmp(11)

transmission(10)

egp (8)

udp (7)

tcp (6)

icmp (50)

ip (40)

at (3)

interface (2)


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Organization of Managed objects

Example: When a SNMP manager requests for the object, it

will send first an OID to the SNMP agent requesting the

information about the object.

The OID : 1.3.6.1.2.1.6.4

iso.org.dod.internet.mgmt.mib-2.tcp.tcpMaxConn

1 3 6 1 2 1 6 4


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Example of an Object Definition

tcpMaxConn OBJECT-TYPESYNTAX INTEGER

ACCESS read-only

STATUS mandatory

DESCRIPTION

The limit on the total numberof TCP

connections the entitycan support.

In entities where themaximum number ofconnection is dynamic,this object shouldcontainthe value 1.

::= {tcp 4}

tcp(mib-2 6)

tcpMaxConn(4)

tcpRtoMax(3)

tcpRtoMin(2)

tcpRtoAlgorithm(1)


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The MIB

Located on each network device

Contains statistics about each managed object:

Actual pieces ofhardware

Configuration parameters

Performance statistics

Information is gathered through SNMP protocol


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The MIB Modules

More than 200 standard MIB modules

Large number of vendor-specific (private) modules

Identification and classification system

Part of the ASN.1 (Abstract Syntax Notation One) objectdefinition language

Naming is achieved in hierarchical (tree) manner where eachbranch point is given both a name and a number

Using t hese two parameters, each object, being a point in thetree, is identifiable through the path from the root to its place in

the tree. MIB modules are found under the MIB-2 branches.

There are modules forTCP, IP, UDP, etc, as well as for system,interface and address translation.


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How is the MIB used?

Analysis of the data is needed in order to form a policy or to takeactions against exceptional conditions.

People are often needed able to think creatively, as well as analytically

foresee problems and act in advance.

Automated management

takes care of the network basically all the time this network isoperational.

cannot take preemptive actions unless more complicated algorithms are needed to achieve successful

automation.


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Organization of a MIB

OBJECTTYPE:

OBJECTTYPE:OBJECTTYPE:

objects specified via SMI

OBJECT-TYPE construct

MIB module specified via SMI

MODULE-IDENTITY

MODULE


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Naming Within a MIB

ISO Object Identifier tree:

Hierarchical naming of all objects.

Each branch point has name, number.

Part of ASN.1.

1.3.6.1.2.1.7.1

ISO

ISO-ident. Org.

USDoD

Internet

udpInDatagrams

UDP

MIB2

management


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ASN.1 object identifier tree (OID)


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MIB Example: UDP Module

Object ID Name Type Comments

1.3.6.1.2.1.7.1 udpInDatagrams Counter32 total # datagrams delivered

at this node

1.3.6.1.2.1.7.2 udpNoPorts Counter32 # undeliverable datagrams

with no application at port

1.3.6.1.2.1.7.3 udpInErrors Counter32 # undeliverable datagrams

for all other reasons

1.3.6.1.2.1.7.4 udpOutDatagrams Counter32 # datagrams sent

1.3.6.1.2.1.7.5 udpTable SEQUENCE one entry for each port

in use by an application, gives

port # and IP address


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MIB examples

They are installed with the SNMP service in the %systemroot%\system32

directory

DHCP.MIBMicrosoft-defined MIB that contains object types for monitoring the network

traffic between remote hosts and DHCP servers

HOSTMIB.MIB

Contains object types for monitoring and managing host resources


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MIB examples

LMMIB2.MIB

Covers workstation and server services

MIB_II.MIB

Contains the Management Information Base (MIB

-II), w

hic

hprovides asimple, workable architecture and system for managing TCP/IP-based

internets

WINS.MIB

Microsoft-defined MIB for the Windows Internet Name Service (WINS)


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SNMP-MIB Browser


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SNMP MIB Browser (3)

Navigation

- MIB Tree

System

sysUpTime

-Notice Lower LHS

- Notice OID


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SNMP PDUs

(1) Get

- Select Go

Get

- RHS has values.

- OID Value


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SNMP PDUs

(2) GetNext

-Selected OID is:

.1.3.6.1.2.1.1.5

-Returned value:

(.1.3.6.1.2.1.1.6)

or

DSG, OReilly Institute,

F.35


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SNMP

(3) Get SubTree

-Position of MIB:

.1.3.6.1.2.1.1

(a.k.a. system)

-RHS values:

Returns all values

below system.


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SNMP

(4) Walk

-MIB Location:

.1.3.6.1.2.1

(a.k.a. mib-2

)

- Returns *ALL* values

under mib-2


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Tables

- MIB Location:

.1.3.6.1.2.1.2.2

(or interfaces)

- Select ifTable,

Go, then Table View.

- Refresh/Poll

Management Information Base

Documents

Transcript of Management Information Base