PLANEAMENTO E GESTÃO DE REDES INFORMÁTICAS COMPUTER NETWORKS PLANNING AND MANAGEMENT

Transcription

1 Mestrado em Engenharia Informática e de Computadores PLANEAMENTO E GESTÃO DE REDES INFORMÁTICAS COMPUTER NETWORKS PLANNING AND MANAGEMENT Arquitecturas de Redes 3 Gestão de Redes e Serviços - Network Architectures 3 Networks and Services Management 1

2 Network Management perspective 2

3 NM Principle of Operation 3

4 Internet Management - SNMP Management is done from the Management Station (manager) It communicates via the SNMP protocol with Agents Information from a node not being able to run an agent can be retrieved from a proxy agent running on another node The biggest part of SNMP describes the kind of information that a specific type of agent provides and the format of it Each managed node holds the information that can be retrieved by SNMP in a special information base called MIB (Management Information Base) (RFC1213) The MIB uses ASN.1 (Abstract Syntax Notation) to describe the managed information as objects. The ASN.1 OBJECT IDENTIFIER is used to uniquely identify every object 4

5 SNMP Management SNMP Simple Network Management Protocol Application-layer protocol for managing TCP/IP based networks. Runs over UDP, which runs over IP NMS (Network Management Station) Device that pools SNMP agent for info. SNMP Agent Device (e.g. Router) running software that understands SNMP language MIB Management Information Base Database of information conforming to SMI. SMI Structure of Management Information Standard that defines how to create a MIB. 5

6 Management Station A Management Station is a Stand Alone system or part of a shared system: interface for human network manager set of management applications data analysis fault recovery interface to monitor and control network translate manager s requirements into monitoring and control of remote elements data base of network management information extracted from managed entities 6

7 Management Agent Agents are found in equipment platforms and/or software e.g., hosts, bridges, hubs, switches, routers allow their management by Management Station respond to requests for information respond to requests for action asynchronously supply unsolicited information 7

8 Distributed NM example 8

9 SNMP Architecture 9

10 SNMP Architecture 10

11 SNMP Protocol 11

12 SNMP Protocol The SNMP protocol is request-response based: A request is sent to an agent from the management station Normally the agent replies with the requested information or confirms the update Various errors can also be reported 12

13 MIB Management Information Base MIB Breakdown - OBJECT-TYPE - String that describes the MIB object. - Object IDentifier (OID). - SYNTAX - Defines what kind of info is stored in the MIB object. - ACCESS - READ-ONLY, READ-WRITE. - STATUS - State of object in regards the SNMP community. - DESCRIPTION - Reason why the MIB object exists. Standard MIB Object: sysuptime OBJECT-TYPE SYNTAX Time-Ticks ACCESS read-only STATUS mandatory DESCRIPTION Time since the network management portion of the system was last reinitialised. ::= {system 3} 13

14 MIB Management Information Base Object IDentifier (OID) 1 iso(1) - Example: org(3) - iso(1) org(3) dod(6) internet(1) dod(6) mgmt(2) mib-2(1) 6 1 internet(1) private(4) system(1) directory(1) 4 Note: 1 2 mgmt(2) 3 experimental(3) ~100% present. - mgmt and private most common. system(1) 1 mib-2(1) 6 tcp(6) - MIB-2 successor to original MIB. 1 interfaces(2) ip(4) - STATUS mandatory, All or nothing in group

15 MIB Management Information Base system(1) group - Contains objects that describe some basic information on an entity. - An entity can be the agent itself or the network object that the agent is on. l system(1) group objects 1 system(1) 2 1 mib-2(1) interfaces(2) - sysdescr(1) à Description of the entity. - sysobjectid(2) à Vendor defined OID string. - sysuptime(3) à Time since net-mgt was last re-initialised. - syscontact(4) à Name of person responsible for the entity. 15

16 MIB Management Information Base 1 MIB - tree view mib-2(1) 1 system(1) 1 syscontact(3) 4 sysdesc(1) sysuptime(3) 3 sysobjectid(2) 2 MIB - syntax view sysuptime OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION The time (in hundredths of a second) since the network management portion of the system was last re-initialized. ::= {system 3} 16

17 MIB Management Information Base SNMP Instances - Each MIB object can have an instance. - A MIB for a router s (entity) interface information iso(1) org(3) dod(6) internet(1) mgmt(2) mib-2(1) interfaces(2) iftable(2) ifentry(1) iftype(3) - Require one iftype value per interface (e.g., 3) - One MIB object definition can represent multiple instances through Tables, Entries, and Indexes. 17

18 MIB Management Information Base Tables, Entries, and Indexes. - Imagine tables as spreadsheets - Three interface types require 3 rows (index #s) - Each column represents a MIB object, as defined by the entry node. ENTRY + INDEX = INSTANCE iftype(3) ifmtu(4) Etc Index #1 Index #2 Index #3 iftype.1[6] iftype.2:[9] iftype.3:[15] ifmtu.1 ifmtu.2 ifmtu.3 18

19 MIB Management Information Base Example MIB Query - If we queried the MIB on iftype we could get: - iftype.1 : 6 - iftype.2 : 9 - iftype.3 : 15 Which corresponds to - iftype.1 : ethernet - iftype.2 : tokenring - iftype.3 : fddi iftype OBJECT-TYPE SYNTAX INTEGER { other(1), ethernet(6), tokenring(9) fddi(15), } etc 19

20 Simple Network Management Protocol Retrieval protocol for the MIB. Can retrieve by: - CLI (Command Line Interface), e.g., snmpwalk, - GUI (Graphical User Interface), e.g., MIB Browser, - Larger applications called Network Management Software NMSoftware is a collection of smaller applications to manage network with illustrations, graphs, etc. NMSoftware runs on Network Management Stations, which can run several different NMS software applications. 20

21 SNMP Commands SNMP has 5 different functions referred to as Protocol Data Units (PDU), which are: (1) GetRequest, aka Get (2) GetNextRequest, aka GetNext (3) GetResponse, aka Response (4) SetRequest, aka Set (5) Trap 21

22 SNMP Commands [Get] GetRequest [Get] - Most common PDU. - Used to ask SNMP agent for values of a particular MIB agent. - NMS sends out one Get PDU for each instance, which is a unique OID string. 22

23 SNMP Commands [GetNext] GetNextRequest [GetNext] - NMS application uses GetNext to walk down (a table) within a MIB. - Designed to ask for the OID and value of the MIB instance that comes after the one asked for. - Once the agent responds the NMS application can increment its count and generate a GetNext. - This can continue until the NMS application detects that the OID has changed, i.e., it has reached the end (of the table). 23

24 SNMP Commands [GetResponse] GetResponse [Response] - Simply a response to a Get, GetNext or Set. - SNMP agent responds to all requests or commands via this PDU. 24

25 SNMP Commands [SetRequest] SetRequest [Set] - Issued by an NMS application to change a MIB instance to the variable within the Set PDU. - For example, you could issue a - GetRequest against a server asking for syslocation.0 and may get HEAVEN as the response. - Then, if the server was moved, you could issue a Set against that server to change its location to HELL. - You must have the correct permissions when using the set PDU. 25

26 SNMP Commands [Trap] Trap - Asynchronous notification. - SNMP agents can be programmed to send a Trap when a certain set of circumstances arise. - Circumstances can be viewed as thresholds, i.e., a Trap may be sent when the temperature of the core breaches a predefined level. 26

27 SNMP Security SNMP Community Strings (like passwords) - 3 kinds: - READ-ONLY: You can send out a Get & GetNext to the SNMP agent, and if the agent is using the same read-only string it will process the request. - READ-WRITE: Get, GetNext, and Set. If a MIB object has an ACCESS value of read-write, then a Set PDU can change the value of that object with the correct read-write community string. - TRAP: Allows administrators to cluster network entities into communities. Fairly redundant. 27

28 SNMP Tools Command Line Interface e.g., snmpwalk Graphical User Interface e.g., ireasoning s MIB Browser Or via 28

29 SNMP MIB Browser (1) Breakdown Left Side pannel shows the SNMP MIB structure. On Lower Left are details of the MIB structure. Right Side pannel will present the MIB values. 29

30 SNMP MIB Browser (2) Discovery - Subnet: 134.XXX.XXX.* - Read Community: public à Start Note IP Address. ß Stop 30

31 SNMP MIB Browser (3) Navigation MIB Tree System sysuptime Notice on Lower Left the values Notice OID 31

32 SNMP MIB Browser (4) SNMP PDU s (1) Get - Select Go à Get - Right pannel has values. - OID Value 32

33 SNMP MIB Browser (5) SNMP PDU s (2) GetNext -Selected OID is: Returned value: ( ) or DSG, O Reilly Institute, F.35 33

34 SNMP MIB Browser (6) SNMP (3) Get SubTree -Position of MIB: (a.k.a. system) -Right pannel has values: Returns all values below system. 34

35 SNMP MIB Browser (7) SNMP (4) Walk -MIB Location: (a.k.a. mib-2) - Returns *ALL* values under mib-2 35

36 SNMP MIB Browser (8) Tables - MIB Location: (or interfaces) - Select iftable, à Go, then Table View. - Refresh/Poll 36

37 SNMP MIB Browser (9) SNMP - Graph - Select a value from the Right pannel, say sysuptime - Highlight and select Go, then Graph. - Interval = 1s à set. 37

38 Management Tools Generic Management Tools Management Tools Development Tools Isolated Platforms Integrated Testers Protocol Analysers Documentation Management Enterprise Management MIBs Agents Applications Internet Tools Problem Management IHM 38

39 Monitoring and Test Tools Single Tools Lower levels Network 39

40 Management Platforms Integrated Tools Network 40

41 Enterprise Management Systems Network 41

42 Business Intelligence Costumer acquisition Costumer care Fraud detection Strategic Decision Support Segmentation & Scoring Campaign Assignment & Management Event Management Contact Management Costumer Information Management Business Intelligence Data Warehouse Business Management Operational Data Store 42

43 TraceRoute Tool 43

44 Activity/Performance Tool 44

45 Example Management Platform 45

46 Example Management Platform 46

47 Example Management Platform 47

48 Example Management Platform 48

49 Example Management Platform 49

50 Example Management Platform 50

51 Example Management Platform 51

52 52

53 References and Readings " Documents: " McCabe, J. D., CHAPTER 7: Network Management Architecture in Network analysis, architecture, and Design, Third Edition. The Morgan Kaufmann series in networking. Amsterdan, Elsevier/ Morgan Kaufmann Publishers, " Monteiro, E. and Boavida F., Capítulo 6: Gestão de Redes in Engenharia de Redes Informáticas, FCA-Editora de Informática, 10ª Edição, " Boavida F. and Bernardes, M. and Vapi, P., Capítulo 6: Monitorização e Medição na Rede in Administração de Redes Informáticas, FCA--Editora de Informática, 1ª Edição,