Chapter 23 Simple Network Management Protocol SNMP Http

Chapter 23 Simple Network Management Protocol (SNMP) Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 1

CONTENTS • • CONCEPT MANAGEMENT COMPONENTS SMI MIB SNMP MESSAGES UDP PORTS SECURITY Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 2

23. 1 CONCEPT Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 3

23. 1 개념 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 4

23. 2 MANAGEMENT COMPONENTS Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 7

23. 2 관리 구성요소 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 8

23. 2 관리 구성요소 SNMP defines the format of packets exchanged between a manager and an agent. It reads and changes the status (values) of objects (variables) in SNMP packets. Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 9

23. 2 관리 구성요소 SMI defines the general rules for naming objects, defining object types (including range and length), and showing how to encode objects and values. Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 10

23. 2 관리 구성요소 SMI defines neither the number of objects an entity should manage, nor names the objects to be managed nor defines the association between the objects and their values. Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 11

23. 2 관리 구성요소 MIB creates a collection of named objects, their types, and their relationships to each other in an entity to be managed. Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 12

23. 2 관리 구성요소 We can compare the task of network management to the task of writing a program. 1. Both tasks need rules. In network management this is handled by SMI. 2. Both tasks need variable declarations. In network management this is handled by MIB. 3. Both tasks have actions performed by statements. In network management this is handled by SNMP. Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 13

23. 3 SMI Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 14

23. 3 SMI <SMI Ü객체 속성 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 16

23. 3 SMI <객체 식별자 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 18

23. 3 SMI All objects managed by SNMP are given an object identifier. The object identifier always starts with 1. 3. 6. 1. 2. 1. Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 19

23. 3 SMI <단순 유형 Type Size Integer 4 bytes A cardinal number between 0 and 232 -1 String Variable Zero or more ASCII characters Object. Identifier Variable An object identifier represented in ASCII digits IPAddress 4 bytes An IP address made of four integers Counter 4 bytes An integer whose value and be incremented form zero to 4, 294, 967, 295; when it reaches its maximum value it wraps back to zero Gauge 4 bytes Same as Counter, but when it reaches its maximum value, it does nto wrap; it remains there until it is reset Time. Ticks 4 bytes A counting value that records time in 1/100 sec-onds Http: //netwk. hannam. ac. kr Description HANNAM UNIVERSITY 21

23. 3 SMI <개념적 데이터 유형 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 23

23. 3 SMI <인코딩 방식 ÜBER(Basic Encoding Rules) 표준 사용하여 전송되는 데이터를 인코딩 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 24

23. 3 SMI Data Class Format Number Tag(Binary) Tag(Hex) Integer 00 0 00010 00000010 02 String 00 0 00100 00000100 04 Object. Identifier 00 0 00110 00000110 06 Sequence sequence of 00 1 10000 00110000 30 IPAddress 01 0 00000 01000000 40 Counter 01 0 00001 01000001 41 Gauge 01 0 00010 01000010 42 Time. Ticks 01 0 00011 01000011 43 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 26

23. 3 SMI <예제 1 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 28

23. 3 SMI <예제 2 ÜString HI 정의 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 29

23. 3 SMI <예제 3 Ü객체 식별자 1. 3. 6. 1(iso. org. dod. internet) 정의 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 30

23. 3 SMI <예제 4 ÜIP 주소 131. 21. 14. 8 정의 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 31

23. 4 MIB Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 32

23. 4 MIB <MIB-2 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 34

23. 4 MIB <MIB 변수 액세스 ÜUdp 그룹의 예 : 단순변수 4개, 레코드 열 1개 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 35

23. 4 MIB Ü단순 변수 w 그룹 식별자 + 변수의 식별자 : 변수 정의 udp. In. Datagrams ====> 1. 3. 6. 1. 2. 1. 7. 1 udp. No. Ports ====> 1. 3. 6. 1. 2. 1. 7. 2 udp. In. Errors ====> 1. 3. 6. 1. 2. 1. 7. 3 udp. Out. Datagrams ====> 1. 3. 6. 1. 2. 1. 7. 4 w 실제 값/내용 : 인스턴스 접미사(0) 사용 udp. In. Datagrams. 0 ====> 1. 3. 6. 1. 2. 1. 7. 1. 0 udp. No. Porsts. 0 ====> 1. 3. 6. 1. 2. 1. 7. 2. 0 udp. In. Errors. 0 ====> 1. 3. 6. 1. 2. 1. 7. 3. 0 udp. Out. Datagrams. 0 ====> 1. 3. 6. 1. 2. 1. 7. 4. 0 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 36

23. 4 MIB Ü테이블 w 테이블 식별자를 사용 w Udp 그룹 : 1개의 테이블 udp. Table ====> 1. 3. 6. 1. 2. 1. 7. 5 w 테이블의 엔트리(sequence) 정의 udp. Entry ====> 1. 3. 6. 1. 2. 1. 7. 5. 1 w 엔트리에 있는 각 항목의 정의 udp. Local. Address ====> 1. 3. 6. 1. 2. 1. 7. 5. 1. 1 udp. Local. Port ====> 1. 3. 6. 1. 2. 1. 7. 5. 1. 2 w 테이블의 특정 인스턴스를 읽기 위해 색인 추가 udp. Local. Address. 181. 23. 45. 14. 23 ====> 1. 3. 6. 1. 2. 1. 7. 5. 1. 1. 181. 23. 45. 14. 23 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 37

23. 4 MIB <Udp 변수와 테이블 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 38

23. 4 MIB <Udp Table에 대한 색인 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 39

23. 4 MIB <사전적 순서 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 41

23. 5 SNMP Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 42

23. 5 SNMP <SNMP PDU Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 44

23. 5 SNMP <SNMP PDU형식 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 47

23. 5 SNMP <오류 종류 Status Name Meaning 0 no. Error No error 1 too. Big Response too big to fit in one message 2 no. Such. Name Variable does not exist 3 bad. Value The Value to be stored is invalid 4 read. Only The value cannot be modified 5 gen. Err Other errors Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 49

23. 6 MESSAGES Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 50

23. 6 메시지 <SNMP 메시지 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 51

23. 6 메시지 <SNMP 메시지에 대한 코드 Data Class Format Number Whole. Tag(Bin ary) Whole. Tag(H ex) Get. Request 10 1 00000 10100000 A 0 Get. Next. Request 10 1 00001 10100001 A 1 Response 10 1 00010 10100010 A 2 Set. Request 10 1 00011 10100011 A 3 Get. Bulk. Request 10 1 00101 10100101 A 4 Inform. Request 10 1 00110 10100110 A 5 Trap(SNMPv 2) 10 1 00111 10100111 A 6 Report 10 1 01000 10101000 A 7 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 52

23. 6 메시지 < 예제 1 Ü 관리자 지국이 라우터가 수신한 UDP 데이터그램의 수를 읽기 위해 Get. Request 메시지 사용 Get. Request Encoding 30 34 Sequence of length 52 02 01 03 INTEGERoflength 1, version=3 30 0 C Sequence of length 12 (header) 02 01 40 INTEGERoflength 1, message. ID=64 02 02 04 00 INTEGERoflength 2, maximumsize=1024 04 01 00 OCTETSTRINGoflength 1, allflagszero 02 00 OCTETSTRING of length 0, no security model 04 00 OCTETSTRING of length 0, no security parameter 30 1 F Sequence of length 31, Data A 0 1 D Get. Request PDU(no encryption) of length 29 02 04 00 01 06 11 INTEGERoflength 04, Request. ID=00010611 16 02 01 00 INTEGERoflength 01, Error. Status=0016 02 01 00 INTEGERoflength 01, Error. Index=0016 30 0 F Sequence of length 15 30 0 D Sequence of length 13 06 09 01 03 06 01 02 01 07 01 00 Object. Id of length 09, udp. In. Datagram 05 00 Null entity of length 00 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 53

23. 6 메시지 < Get. Request 메시지 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 54

23. 7 UDP PORTS Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 55

23. 7 UDP 포트 <SNMP의 포트 번호 Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 57

23. 8 SECURITY Http: //netwk. hannam. ac. kr HANNAM UNIVERSITY 58