MRTG

Speaker: Yan-Shiang Wang

Adviser: Quincy Wu

Date: 2005/11/23

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Network Management

OSI CMIP (Common Management Information Protocol) designed 1980

SNMP de facto network management standard

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SNMP

Simple Network Management Protocol application layer protocol facilitates the exchange of

management information between network devices

part of the TCP/IP UDP port 161

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SNMP-basic components

managed devices sometimes called network elements

agents network-management software module

network-management systems (NMSs) executes applications that monitor and co

ntrol managed devices

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SNMP-basic components (cont.)

Manager Agent

SNMP SNMP

UDP UDP

IP IP

Interface Interface

network

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SNMP-basic commands

read NMS examines different variables

write NMS changes the values of variables

trap used by managed devices to asynchronously

report events to the NMS traversal operations

which variables a managed device supports sequentially gather information in variable tables

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MIB

Management Information Base collection of information that is organized

hierarchically managed object (or MIB object or MO)

scalar and tabular each resource to be managed data variable

object identifier (or object ID or OID)

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MIB (cont.)

MIB

Agent

SNMP

UDP

IP

Interface

resources

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MIB tree exampleroot

ccitt(0) iso(1) iso-ccitt(2)

standard(0) registration-authority(1)

identified-organization(3)

dod(6)

internet(1)

member-body(2)

directory(1) mgmt(2) experimental(3) private(4) security(5) snmpV2(6)

enterprise(1)

ucdavis(2021)

memory(4)

memTotalFree(11)

systemStats(11)

ssCpuRawUser(50)

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MIB tree example

memTotalFree (MO) .1.3.6.1.4.1.2021.4.11 (OID)

ssCpuRawUser (MO) .1.3.6.1.4.1.2021.11.50 (OID)

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SNMPv1

RFC-1157 operates over UDP, IP, CLNS, DDP, IPX

SMI(Structure of Management Information) RFC-1155 ASN.1 data types

name, syntax, and encoding SMI-specific data types

simple, and application-wide SNMP MIB tables

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SNMPv2

evolution of the initial version draft standard currently SMI(Structure of Management Information) RFC-1902 modules

MIB modules, compliance statements, and capability statements

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SMI(Structure of Management Information) example

/usr/local/share/snmp/mibs/UCD-SNMP-MIB.txt memTotalFree OBJECT-TYPE SYNTAX Integer32 MAX-ACCESS read-only STATUS current DESCRIPTION "Total Available Memory on the host" ::= { memory 11 }

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SMI(Structure of Management Information) example

/usr/local/share/snmp/mibs/UCD-SNMP-MIB.txt ssCpuRawUser OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "user CPU time." ::= { systemStats 50 }

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SNMPv1 vs. SNMPv2

request/response protocol Get, GetNext, Set, and Trap

adds/enhances protocol SNMPv2 Trap GetBulk and Inform

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SNMP Service

Getretrieve objects

GetNextretrieve next objects

Setupdate objects

Trapreport events

Get Request

Get ResponseManager Agent

GetNext Request

Get ResponseManager Agent

Set Request

Get ResponseManager Agent

Trap RequestManager Agent

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GetNext

MIB Tree only leaf objects

have values

1 2 3 4 1 2

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SNMP example

snmptranslate .1.3.6.1.4.1.2021.11.50.0 OID to MO

snmptranslate -On UCD-SNMP-MIB::ssCpuRawUser.0 MO to OID

snmptranslate -Of UCD-SNMP-MIB::ssCpuRawUser.0 show total path

snmptranslate -IR ssCpuRawUser show total MO

snmptranslate -IR -Td ssCpuRawUser show MO’s content

snmptranslate -IR -Tp ucdavis show tree structure

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SNMP example (cont.)

snmpget -c mrtg -v 2c localhost ssCpuRawUser.0 -c: community -v: version target MO.0 show MO’s value

snmpgetnext -c mrtg -v 2c localhost ssCpuRawUser.0 show MO’s next relative value

snmpwalk -v 2c -c mrtg localhost show all system MO’s value

snmpwalk -v 2c -c mrtg localhost systemStats show MO’s family value

snmptable -v 2c -Cw 80 -c mrtg localhost sysORTable -Cw: width show MO’s value (tabular)

snmptable -v 2c -Cw 80 -c mrtg localhost dskTable show MO’s value (tabular)

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MRTG

Multi Router Traffic Grapher required

net-snmp libpng: png library gd: draw graph zlib: zip graph perl apache

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MRTG - configure

/usr/local/share/snmp/snmpd.conf rocommunity mrtg syslocation Lab syscontact root@localhost

cfgmaker mrtg@localhost > mrtg.cfg mrtg mrtg.cfg indexmaker -output index.html mrtg.cfg

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MRTG - addition

CPU Utilization systemStats::ssCpuRawUser.0

Memory Usage memory::memAvailReal.0

Disk Usage dskTable::dskPercent.0

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