Text Book: Computer Networking: A Top Down Approach Featuring the Internet 3rd edition, by Jim Kurose and Keith Ross, Addison-Wesley

Transcription

1 Network Management Text Book: Computer Networking: A Top Down Approach Featuring the Internet 3rd edition, by Jim Kurose and Keith Ross, Addison-Wesley these slides are based on USP Network Management slides from Schweitzer, Gabos, Redigolo and Carvalho and some were based on Kurose and Ross 1

2 Network Management What is network management? but first what is management? (from an engineer point of view, of course!) 2

3 Illustrating Network Management* S3 S4 H1 H2 H3 H4X interface is overloaded! S1 S2 network load is ok here! hmmm... failed! Internet 3 *a first approach!

4 What is Network Management? "Network management includes the deployment, integration and coordination of the hardware, software, and human elements to monitor, test, poll, configure, analyze, evaluate, and control the network and element resources to meet the real-time, operational performance, and QoS requirements at a reasonable cost" 4

5 Network Management Goals Optimal performance from all enterprise resources Set standards and action plans guarantee the quality level of services provided 5

6 The Management Pyramid SDH PDH Business Management Service Management ATM FR Network Management Network Elements Management Network Elements 6

7 Network Management WHY is Network Management needed after all? log network events knowledge of the network topology/configuration parameters changing network configuration parameters monitor the network security verify the demand for network resources define thresholds for alarm triggers detect, diagnose and prevent faults monitor and control the network performance 7

8 Network Management standard /best practice Network Management Network OAM&P Operations Administration Maintenance Provisioning 8

9 Network Management Network Management Provisioning Operations Maintenance Planning Network Layout Fault Management / Net. Recovery Configuration Management Performance Management Security Management Accounting Management Report Management Inventory Management Data Analysis and Routing Fault Management Trouble Tickets Management Deployment Repairs Maintenance Tests 9

10 Management Functional Areas FCAPS ISO telecom net mgmt model/framework Fault Management Configuration Management Accounting Management Performance Management Security Management 10

11 Fault Management guarantee the continuous network operation detect, identify, isolate and log problems run network diagnose tests, investigate fault reasons and start fixing it acknowledge and log the arrival of event reports 11

12 Configuration Management manage the system life cycle and its configuration identify hardware and software components from the system and define an appropriate level of control for each one monitor each component and document all significant changes keep a history of the status of each network component change the system s configuration in order to alleviate network congestions, isolate faults or to conform with new demands from network users 12

13 Accounting Management control the usage of network resources define costs and fees for usage of network resources inform the resulting costs to the network user define and/or authorize limits for bandwidth consumption 13

14 Performance Management monitor and control the daily network operation transmission rates devices and active services status traffic flow network delay, etc pinpoint overloaded links and identify risk situations keep an history of the network conditions for late analysis 14

15 Security Management manage the mechanisms and procedures that provide security to the network resources keep and handle the security logs maintenance of the security policy 15

16 SLA Service Level Agreement specific performance metrics acceptable levels of network provider performance according to the those metrics, e.g.: service availability latency throughput outage notification 16

17 General Network Management System Managed devices (and managed objects) Information databases (aka MIB) Management entities Agents running on every managed device Managers running on a NOC Protocol for (management) information exchange API (Application Programming Interface) User interface 17

18 Network Management Operation Network managing entity (manager) collect information from the network managed entities (agents) network managed entities include: routers, host, servers, etc. MIB (Management Information Base) define the entries (objects) that are kept by a network managed entity 18

19 Open Architectures for Management OSI architecture (ISO) Open System Interconnection SNMP (IETF) architecture Simple Network Management Protocol TMN architecture (ITU-T) Telecommunication Management Network Web Management architectures 19

20 OSI Management Model The OSI management model defines management infrastructure management components the presentation of management information services and protocols for exchanging management info. 20

21 OSI Management Environment Components CMIP CMIP MANAGER MANAGER MANAGER CMIP CMIP AGENT CMIP CMIP AGENT managed objects AGENT AGENT managed objects managed objects managed objects CMIP = Common Management Information Protocol 21

22 OSI Management Infrastructure Systems Management support function on every layer Manager Agent MIB LME LME LME LME LME LME LME SMAE APPLICATION PRESENT. SESSION TRANSPORT NETWORK DATA LINK PHY CMIP LME LME LME LME LME LME LME SMAE APPLICATION PRESENT. SESSION TRANSPORT NETWORK DATA LINK PHY MIB MIB - Management Information Base SMAE - System Management Application Entity 22 CMIP - Common Management Information Protocol LME - Layer Management Entity

23 OSI Management Infrastructure Layered Management n th layer layer n th management protocol n th layer management of resources related with a single layer the layered management protocol is independent from management protocols from other layers Layered Operations restricted to a single communication instance in one layer 23

24 IETF Network Management Framework related to section 8.3 from the textbook (but a far more deep approach here!!!) slides from Schweitzer, Gabos, Redigolo and Carvalho Computer Networking: A Top Down Approach Featuring the Internet 2nd edition, by Jim Kurose and Keith Ross, Addison-Wesley,

25 SNMP Overview SNMP (Simple Network Management Protocol) designed for managing Internet nodes. Internet-Standard Management any network running TCP/IP can be managed with SNMP SNMP was a quickly designed and deployed network management was clearly needed OSI management was not completed SNMP was an intermediary step SNMP is the de facto network management standard new versions were released: SNMPv2 and SNMPv3 (1999) 25

26 SNMP Architecture Managing stations - managers run a management application that monitor and control the net. Managed hosts - agents devices that hosts management agents SNMP protocol receive requests from managers and reply them execute commands received from managers give information about objects communication protocol for transporting management information between a manager and an agent 26

27 Network Management System (NMS) behaving as a manager and as an agent SNMP Manager SNMP Agent SNMP SNMP Agent SNMP Manager SNMP Agent SNMP Network Device SNMP Agent SNMP Network Device 27

28 SNMP Architecture Elements Management Information Base (MIB): distributed information store of network management data definitions of network management objects Structure of Management Information (SMI): data definition language for MIB objects (e.g. data types) SNMP protocol data communication protocol between agents and managers exchanged messages / commands 28

29 SNMP Protocol Management information can be obtained in two-ways: manager manager request response trap msg agent data agent data Managed device Managed device request/response mode trap mode 29

30 SNMP (SNMPv1) 5 SNMPv1 messages were defined: get-request manager agent get-next-request manager agent set-request manager agent response agent manager trap agent manager 30

31 SNMP Message SNMP message Header + PDU HEADER SNMP PDU Header Version Number Community Name weak form of authentication Version Number Community Name 31

32 SNMP PDU (protocol data unit) SNMP Get/Set/Response Messages response PDU only PDU Type Request ID Error Status Error Index Objects Get/Set/Response header objects to get/set SNMP Trap Messages PDU Type Enterprise Agent Address Trap Type Specific Trap Code Timestamp Objects Trap header 32 Trap info

33 SNMPv2 SNMPv1 vs. OSI CMOT (CMIP running over TCP/IP) SNMP as CMIP (mgr to mgr) SNMP was the de-facto standard SNMP modules included in systems and network devices but SNMPv1 needed to be improved SNMPv2 was designed (1993) 33

34 SNMPv2 Manager-to-Manager messages were included SMI (Structure of Management Information) was included Agreements for textual descriptions SNMP conformity aspects Inheritance Tables MIB Inheritance Port Mapping for transport protocol UDP (RFC1906) port 161 port 162 (trap messages) SNMP UDP 34

35 SNMPv2 Messages Message type GetRequest GetNextRequest GetBulkRequest InformRequest SetRequest Response Function Manager to Agent: get me data (instance,next in list, block) Manager-to-Manager: here s MIB value Manager to Agent: set MIB value Agent to Manager: value, response to Request Trap Agent to Manager: inform manager of exceptional event 35

36 Manager Database Management in a SNMP Network SNMP Manager SNMP Agent SNMP Manager App SNMP Agent App SNMP UDP IP DL PHY PHY Medium 36 GetRequest GetNextRequest SetRequest Response Trap GetRequest GetNextRequest SetRequest Response Trap SNMP Messages SNMP UDP IP DL PHY Agent Database

37 Going beyond SNMPv2: SNMPv3 SNMPv1 and SNMPv2 no security at all! SNMPv3 was designed to improve security (1999) security infrastructure for all 3 SNMP versions + modularity for documentation and architecture ( views ) + coexistence of all 3 protocols in a single managing entity + explicitly definition of services and application primitives several messages types were formalized command generators/responder, notification originator/receiver, proxy forwarder 37

38 SNMPv3 Data Encryption DES Authentication HMAC keyed-hash function of the encrypted message Protection against Replay attacks nonce / cookie View-based Access Control Model (VACM) RFC2575 database of access rights & policies for users Local Configuration Datastore (LCD) database is a managed object itself 38

39 Some SNMPv3 standards Some SNMPv3 RFC: RFC 2271 SNMP management frameworks architecture RFC 2272 message processing and dispatching RFC 2273 SNMPv3 applications RFC 2274 user based security model UserID and Password RFC 2275 access control 39

40 Management Information Base (MIB) Every agent has a local database keep the current status of the device parameters MIB manager monitors agents through the information stored in MIB MIB stores data objects IETF MIB standards: RFC1212 MIB-I specification RFC1213 MIB-II specification both MIB-I and MIB-II can be implemented in SNMPv1 40

41 Network Management System (NMS) behaving as a manager and as an agent MIB SNMP Manager SNMP Agent SNMP SNMP Agent SNMP Manager MIB SNMP SNMP MIB SNMP Agent Network Device SNMP Agent Network Device MIB objects defined with SMI OBJECT-TYPE 41

42 SNMP Naming HOW TO name and identify objects? every possible standard object in every possible network standard IETF adopted the ISO Object Identifier tree: hierarchical naming of all objects each branch point has name & number 42

43 OSI Object Identifier Tree 43

44 OSI Object Identifier ISO ISO-ident. Org. US DoD Internet udpindatagrams UDP MIB2 management ISO ISO-ident. Org. US DoD Internet Karlstad University enterprises and universities codes private 44

45 MIB-I and MIB-II MIB-I name (OBJECT DESCRIPTOR), syntax (ASN.1) and encoding (BER) MIB-II mib-2 OBJECT IDENTIFIER ::= {mgmt 1} extra attribute for the status of the managed object System, interfaces, ip, tcp, udp, etc 45

46 SMI Structure of Management Information ASN.1 ASN.1 language to define management information residing in a managed network entity well-defined and unambiguous syntax and semantics of data RFC2578 defines 11 basic data types: INTEGER Integer32 Unsigned32 OCTET STRING OBJECT IDENTIFIER ASN.1 IPaddress Counter32 Counter64 Guage32 Time Ticks Opaque ASN.1 46

47 SMI OBJECT-TYPE RFC specify data type, status and semantics OBJECT-TYPE SYNTAX data type MAX-ACCESS R/W/C STATUS object definition (current/obsolete/deprecated) DESCRIPTION textual definition of the object ipforwarding OBJECT-TYPE SYNTAX INTEGER { forwarding(1), -- acting as a router notforwarding(2) -- NOT acting as a router } MAX-ACCESS read-write STATUS current DESCRIPTION "The indication of whether this entity is acting as an IP router in respect to the forwarding of " 47 ::= { ip 1 }

48 SMI MODULE-IDENTITY related MIB objects can be grouped together in a MIB module MIB modules are specified via SMI RFC2011 MIB modules that defines managed objects for IP and ICMP RFC2012 MIB module for TCP RFC2013 MIB module for UDP RFC2021 MIB module for RMON (remote monitoring) contains: OBJECT-TYPE definitions of the managed objects clauses to document contact information, date of last update, revision history, textual description of the module. 48

49 SMI tcpmib MODULE-IDENTITY LAST-UPDATED " Z" ORGANIZATION "IETF SNMPv2 Working Group CONTACT-INFO " Keith McCloghrie Postal: Cisco Systems, Inc. 170 West Tasman Drive San Jose, CA US Phone: DESCRIPTION "The MIB module for managing TCP implementations. REVISION " Z DESCRIPTION "The initial revision of this MIB module was part of MIB- II. ::= { mib-2 49 } 49

50 MIB and SMI SMI MODULE-IDENTITY MODULE OBJECT TYPE: OBJECT TYPE: OBJECT TYPE: objects specified via SMI OBJECT-TYPE construct 50

51 MIB example: UDP module Object ID Name Type Comments ::= { udp 1 } udpindatagrams Counter32 total # datagrams delivered at this node ::= { udp 2 } udpnoports Counter32 # underliverable datagrams - no app at port ::= { udp 3 } udpinerrors Counter32 # undeliverable datagrams all other reasons udpoutdatagrams Counter32 # datagrams sent ::= { udp 4 } udptable SEQUENCE one entry for each port in use by app, gives port # and IP address ::= { udp 5} 51

52 SNMP Management: RMON SNMP success increasing # of managed entities & components SNMPv1 introduced the remote network management controlled from a NOC Network Operation Center Remote monitoring probes placed in several network segments 52

53 RMON Remote Network Monitoring added to SNMP expands the SNMP scope specifies a remote monitoring MIB included in MIB II each RMON device monitor a network segment and analyzes it. S2 S4 H1 H2 S1 53

54 Why RMON? network management traffic is reduced # of active agents needed in a network is reduced network segments can be monitored continuously better statistical results better network control faults can be quickly diagnosed and logged Productivity is increased 54

55 ASN.1 Abstract Syntax Notation 1 related to section 9.4 from the textbook Computer Networking: A Top Down Approach Featuring the Internet 2nd edition, by Jim Kurose and Keith Ross, Addison-Wesley,

56 The Presentation Problem in a computer network it is usual to have several different: computer architectures OS, compilers, etc so how are data exchanged between different systems? maybe perfect memory-to-memory copy? 56

57 Perfect Memory-to-Memory Copy struct { char c; int i; } test; test.c = a ; test.i = 259; test.c test.i a memory addressing a memory addressing Big Endian Little Endian SUN SPARC, Motorola INTEL DEC/Compaq Alpha 57

58 Perfect Memory-to-Memory Copy another example: Intel 80x86 (32bit word) memory dump char c1 = 1 char c2 = 2 short s = 255 //0x00FF long l = 0x FF memory addressing 58

59 A Real Life Analogy Computer Networking: A Top Down Approach Featuring the Internet 2nd edition, by Jim Kurose and Keith Ross, Addison-Wesley,

60 Some Potential Solutions 1 st option sender learns receiver s format sender translates into receiver s format sender sends 2 nd option sender sends receiver learns sender s format receiver translate into receiver-local format 3 rd option sender translates host-independent format sends receiver translates to receiver-local format 60

61 Solving the presentation problem 1 st step translate local-host format to host-independent format 2 nd step transmit data in host-independent format 3 rd step translate host-independent format to remote-host format grandmother aging 60 s hippie today s teenager 61

62 ASN.1 Abstract Syntax Notation 1 presentation service data definition language defines data types and object constructors ISO standard X.680 used extensively in Internet Basic Encoding Rules (BER) specify how ASN.1-defined data objects are transmitted each transmitted object has Type, Length, Value (TLV) encoding 62

63 TLV Encoding Transmitted data identify itself T data type, one of ASN.1-defined types L length of data in bytes V value of data, encoded according to ASN.1 standard Tag Type Boolean Integer Bitstring Octet string Null Object Identifier Real 63

64 TLV encoding Value = 259 Length = 2 bytes Type = 2 integer Value = 5 octets (chars) Length = 5 bytes Type = 4 octet string 64

65 Network Management Systems slides from Schweitzer, Gabos, Redigolo and Carvalho 65

66 Management Products 2 flavors of network management products: standalone management applications management platforms 66

67 Standalone Applications usually designed to run on windows platforms no interoperability with management tools from other vendors main tasks device testing protocol analyzers Internet tools GUI for one vendor only some tasks can be executed using a GUI i.e. enabling/disabling ports 67

68 Standalone Applications devices from other vendors can be managed sometimes if possible no graphic interface MIB are manipulated directly some standalone management applications: 3Com Transcend Cisco CiscoWorks IBM Nways Novell ZENWorks 68

69 Management Platforms management all the way from backbone to desktop scalable solutions pro-active management tools Management Applications NOVELL modules for the management platform management platforms Agents 69 source: 3Com

70 Management Platforms usually for Unix/Windows NT platforms goal is to provide both network and systems management on top of the manag. platform are added additional modules manag. platforms usually have an API to integrate these modules framework software for specific devices or functionalities that can aggregate new features to the system 70

71 Management Platforms GUI management for several vendors embedded modules already include private MIB enabling/disabling ports can be executed graphically, for instance some management platforms Sun Solstice Site Manager / Enterprise Manager IBM/Tivoli - Tivoli Framework / Netview Computer Associates - Unicenter TNG Enterasys Spectrum HP OpenView 71

72 Management Platforms some modules for management platforms 3Com Transcend for Solstice Site Manager CiscoWorks for HP OpenView IBM Nways for Tivoli NetView APC PowerChute for MS-SMS McAffee VirusScan for Novell ManageWise 72

73 Web Management Traditional management platforms are inconvenient centralized management architecture managing station (manager) needs a high processing power platform dependence (private MIB) interaction between management platforms was practically null cost 73

74 Web Management Web distributed infrastructure known navigation paradigm browsing platform independent GUI Java, HTML Initial idea: Management should be executed through a browser from any machine connected to the Internet disassociate the management GUI from the management tools 74

75 Web Management Other ideas to use existing web protocols SSL HTTP password authentication Digital Certificates ACL Access Control Lists to integrate different management tools different web sites (vendor web sites) XML, Web Services 75

76 Open Source NMS Nagios OpenNMS ZenOSS 76

77 Nagios 77

78 78

79 79

80 Management Platform Model slides from Schweitzer, Gabos, Redigolo and Carvalho 80

81 Features network topology discovery define a network map identification of faults terminal emulation automatic intervention on-line help reporting MIB management 81

82 Network Topology Discovery identify resources of the corporative network create a database with objects that will be managed manual register of non-identified resources 82

83 Define a network map Objects representing the resources to be managed for fast fault identification using alarm, colors alarm notification network map is automatic created several views of the managed network great number of managed resources implementation of differentiated security levels operation distributed geographically 83

84 Identification of Faults information about managed resources event handling requested information non-requested information traps fault isolation prevent a fault to be propagated within the network saving time for fixing / correcting faults alarm notification through different communication media web server, pagers, cellular phones, fax or 84

85 Other Features Terminal emulation command line access for managed devices configuration overview and configuration changes TELNET (TCP/IP) Automatic intervention pro-active management management system can fix / correct network parameters port reconfiguration 85

86 Other Features On-line Help platform features & tools walkthrough for network problems and action that should be taken Reporting network events reporting MIB management different vendors have different MIB standards managing using a private MIB 86

87 Acknowledgments many thanks to: Christiane Schweitzer, Denis Gabos, Fernando Redigolo and Tereza Carvalho from the Network and Computer Architecture Laboratory (LARC) from the Department of Computer Engineering - Escola Politécnica - University of Sao Paulo (USP) - Brazil. contact them at { chrism, dgabos, fernando, carvalho larc.usp.br 87