MRTG Speaker: Yan-Shiang Wang Adviser: Quincy Wu Date: 2005/11/23

2 Network Management OSI CMIP (Common Management Information Protocol)  designed 1980 SNMP  de facto network management standard

3 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

4 SNMP-basic components managed devices  sometimes called network elements agents  network-management software module network-management systems (NMSs)  executes applications that monitor and control managed devices

5 SNMP-basic components (cont.) ManagerAgent SNMP UDP IP Interface network

6 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

7 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)

8 MIB (cont.) MIB Agent SNMP UDP IP Interface resources

9 MIB tree example root 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)

10 MIB tree example memTotalFree (MO)  (OID) ssCpuRawUser (MO)  (OID)

11 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

12 SNMPv2 evolution of the initial version draft standard currently SMI (Structure of Management Information) RFC-1902 modules  MIB modules, compliance statements, and capability statements

13 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 }

14 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 }

15 SNMPv1 vs. SNMPv2 request/response protocol  Get, GetNext, Set, and Trap adds/enhances protocol  SNMPv2 Trap  GetBulk and Inform

16 SNMP Service Get retrieve objects GetNext retrieve next objects Set update objects Trap report events Get Request Get Response ManagerAgent GetNext Request Get Response ManagerAgent Set Request Get Response ManagerAgent Trap Request ManagerAgent

17 GetNext MIB Tree  only leaf objects have values

18 SNMP example snmptranslate  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

19 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)

20 MRTG Multi Router Traffic Grapher required  net-snmp  libpng: png library  gd: draw graph  zlib: zip graph  perl  apache

21 MRTG - configure /usr/local/share/snmp/snmpd.conf  rocommunitymrtg  syslocationLab  cfgmaker > mrtg.cfg mrtg mrtg.cfg indexmaker -output index.html mrtg.cfg

22 MRTG - addition CPU Utilization  systemStats::ssCpuRawUser.0 Memory Usage  memory::memAvailReal.0 Disk Usage  dskTable::dskPercent.0

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