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Chu-Sing Yang

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Title: Chu-Sing Yang


1
Introduction to Network Management
  • Chu-Sing Yang
  • Department of Electrical Engineering
  • National Cheng Kung University

2
Outline
  • Introduction
  • Network Management Requirement
  • SNMP Family
  • OSI Management Function Areas
  • Network Management System
  • Network Management Software Architecture
  • Distributed Network Management
  • Proxies

3
Outline
  • Introduction
  • Network Management Requirement
  • SNMP Family
  • OSI Management Function Areas
  • Network Management System
  • Network Management Software Architecture
  • Distributed Network Management
  • Proxies

4
The Case for Management
Remote User
  • Typical problem
  • Remote user arrives at regional office and
    experiences slow or no response from corporate
    web server
  • Where do you begin?
  • Where is the problem?
  • What is the problem?
  • What is the solution?
  • Without proper network management, these
    questions are difficult to answer

Regional Offices
WWW Servers
Corp Network
5
The Case for Management
Remote User
  • With proper management tools and procedures in
    place, you may already have the answer
  • Consider some possibilities
  • 1. What configuration changes were made
    overnight?
  • 2. Have you received a device fault notification
    indicating the issue?
  • 3. Have you detected a security breach?
  • 4. Has your performance baseline predicted this
    behavior on an increasingly congested network
    link?

Regional Offices
WWW Servers
Corp Network
6
Solving Problem Procedure
  • An accurate database of your networks topology,
    configuration, and performance
  • A solid understanding of the protocols and models
    used in communication between your management
    server and the managed devices
  • Methods and tools that allow you to interpret and
    act upon gathered information

High Availability
Response Times
Security
Predictability
7
Introduction
  • Network Management System (NMS)
  • Automatic versus human effort
  • Increased network size
  • Increased complexity
  • Heterogeneous equipment
  • Equipment from multiple vendors

8
Outline
  • Introduction
  • Network Management Requirement
  • SNMP Family
  • OSI Management Function Areas
  • Network Management System
  • Network Management Software Architecture
  • Distributed Network Management
  • Proxies

9
Network Management Requirements
  • Ease of use
  • Security features
  • Restoral capability
  • Ability to delete/add
  • Ability to monitor network availability
  • Traffic rerouting
  • Improved automation
  • User registration
  • Improved reporting
  • Ability to monitor response time

10
Network Management Requirements
  • Control corporate strategic assets
  • Control complexity
  • Improve service
  • Balance various needs
  • Reduce downtime
  • Control cost

11
Outline
  • Introduction
  • Network Management Requirement
  • SNMP Family
  • OSI Management Function Areas
  • Network Management System
  • Network Management Software Architecture
  • Distributed Network Management
  • Proxies

12
Introduction to SNMP
  • Simple Network Management Protocol
  • Provides a tool
  • for multi-vender, interoperable network
    management
  • used across a broad spectrum of product types
  • include end systems, bridges, switches, routers
    and telecommunications equipment
  • TCP/IP based

13
Simple Network Management Protocol
  • A set of standards for network management
  • a protocol
  • a data base structure specification
  • a set of data objects

14
SNMP Family
  • SNMPv1
  • Proposed in 1989
  • SNMPv2
  • Proposed in 1993
  • Revised in 1995
  • An upgrade to SNMPv1
  • Add functional enhancements to SNMP and codify
    the use of SNMP on OSI-based networks

15
SNMP Family (cont.)
  • SNMPv3
  • Issued in 1998
  • Define a security capability for SNMP and an
    architecture for future enhancements
  • Used with the functionality provided by SNMPv2 or
    SNMPv1

16
RMON
  • Remote network MONitoring
  • a supplement to SNMP
  • extend the capabilities of SNMP to include
    management of LANs as well as the devices
    attached to those networks
  • RMON 1 issued in 1991
  • RMON 2 issued in 1995

17
Outline
  • Introduction
  • Network Management Requirement
  • SNMP Family
  • OSI Management Function Areas
  • Network Management System
  • Network Management Software Architecture
  • Distributed Network Management
  • Proxies

18
OSI Management Functional Areas
  • Fault management
  • Configuration management
  • Accounting management
  • Performance management
  • Security management

19
Fault Management
  • The facilities that enable the detection,
    isolation, and correction of abnormal operation
    of the OSI environment
  • What is a fault?
  • an abnormal condition that requires management
    attention (or action) to repair
  • indicated by failure to operate correctly or by
    excessive errors
  • Communication line is cut
  • A crimp in the cable
  • Certain errors may occur occasionally and are not
    normally considered to be faults

20
Fault Management
  • When a fault occurs
  • Determine exactly where the fault is
  • Isolate the rest of the network from the failure
  • Reconfigure or modify the network to minimize the
    impact of operation
  • Repair or replace the failed components

21
User requirements for Fault Management
  • Fast and reliable problem resolution
  • Receive notification and correct the problem
    immediately
  • Requires rapid and reliable fault detection and
    diagnostic management
  • Provides fault tolerance
  • Redundant components and alternate communication
    routes
  • Fault management capability itself should be
    redundant
  • Keep informed of the network status
  • Reassurance of correct network operation through
    mechanisms that use tests or analyze dumps, logs,
    alerts, or statistics
  • Problem tracking and control
  • Ensure the problem is truly resolved and no new
    problems are introduced
  • Fault management should have minimal effect on
    network performance

22
Configuration Management
  • Configuration management is concerned with
  • Initializing a network
  • Gracefully shutting down part or all of the
    network
  • Maintaining, adding, and updating the
    relationships among components and the status of
    components themselves during network operation

23
Requirements for Configuration Management
  • The network manager needs the capability to
  • Identify initially the components that comprise
    the network
  • Define and change the connectivity of components
  • Define and modify default attributes, and load
    the predefined sets of attributes into the
    specified network components
  • Reconfigure a network for performance evaluation,
    network upgrade, fault recovery or security
    checks
  • End users want to inquire about the upcoming
    status of resources and their attributes before
    reconfiguration
  • Generate configuration reports
  • Periodic basis
  • Response for a request
  • Only authorized end users can manage and control
    network operation (software distribution and
    updating)

24
Accounting Management
  • The facilities that enable
  • charges to be established for the use of managed
    objects
  • costs to be identified for the use of those
    managed objects

25
Accounting Management
  • Network managers track the use of network
    resources by end user or end-user class
  • An end user or group of end users may be abusing
    its access privileges and burdening the network
    at the expense of other users
  • End users may be making inefficient use of the
    network, and network manager can assist in
    changing procedures to improve performance
  • The network manager is easier to plan for network
    growth if end user activity is known in
    sufficient detail

26
Requirements for Accounting Management
  • The network manager can specify
  • the kinds of accounting information to be
    recorded at various nodes
  • the desired interval between sending the recorded
    information to higher-level management nodes
  • the algorithms to be used in calculating the
    charging
  • Generate accounting reports
  • Provide the capability to verify end users
    authorization to access and manipulate the
    information

27
Performance Management
  • The facilities needed to evaluate
  • the behavior of managed objects
  • the effectiveness of communication activities
  • Functions of performance management
  • Monitoring
  • Tracks activities on the network
  • Controlling
  • Enables performance management to make
    adjustments to improve network performance

28
Issues of Performance Management
  • What is the level of capacity utilization?
  • Is there excessive traffic?
  • Has throughput been reduced to unacceptable
    levels?
  • Are there bottlenecks?
  • Is response time increasing?

29
To Deal the Issues of PM
  • The network manager focus on some initial set of
    resources to be monitored in order to assess
    performance levels
  • Appropriate metrics and values with relevant
    network resources as indicators of different
    levels of performance
  • The count of retransmission on a transport
    connection
  • Monitor many resources to provide information in
    determining network operating level
  • Collect and analyze information, and then using
    the resultant analysis as feedback to the
    prescribed set of values

30
User Requirements for Performance Management
  • End users want to know
  • the average and worst case response times
  • the reliability of network services
  • Performance statistics can help managers
  • Plan, manage and maintain large networks
  • Recognize potential bottlenecks in advance
  • balance or redistribute traffic load by changing
    routing tables

31
Security Management
  • The facilities that address those aspects of OSI
    security essential to
  • Operate OSI network management correctly
  • Protect managed objects
  • network resources
  • end user information
  • End users want to know
  • the proper security policies are in force and
    effective
  • the management of security facilities is itself
    secure

32
Issues of Security Management
  • Managing information protection, and access
    control facilities
  • Generating, distributing and storing encryption
    keys
  • Passwords, authorization or access control
    information must be maintained and distributed
  • Monitoring and controlling access to computer
    networks and to all or part of the network
    management information
  • SM involves with the collection, storage, and
    examination of audit records and security logs
  • the enabling and disabling of these logging
    facilities

33
Outline
  • Introduction
  • Network Management Requirement
  • SNMP Family
  • OSI Management Function Areas
  • Network Management System
  • Network Management Software Architecture
  • Distributed Network Management
  • Proxies

34
Network Management Systems (NMS)
  • NMS is a collection of tools for network
    monitoring and control
  • Designed to view the entire network as a unified
    architecture
  • addresses and labels assigned to each point
  • specific attributes of each element and link
    known to the system
  • Single operator interface with a powerful but
    user-friendly set of commands
  • a minimal amount of separate equipment
    (hardware/software) is necessary
  • NMS software resides in the host computers and
    communications processors (bridges, routers)

35
Network Management Systems
  • The active elements of the network provide
    regular feedback of status information to the
    network control center
  • NMS for single vendor equipment versus for
    multiple-vendor network
  • Two or more network control centers are used
  • for high availability (backup)
  • one center is idle or collecting statistics
  • the other center is used for control

36
Network Management System

37
Network Management Configuration
  • Network Management Element (NME)
  • Contains a collection of software devoted to the
    NM task in each network node
  • collects statistics
  • Stores statistics locally
  • Responds to commands from network control center
    (manager)
  • Transmit collect statistics to manager
  • Change a parameters (a timer in a transport
    protocol)
  • Provide status information
  • Generate artificial traffic for testing
  • Send messages to network control center for
    significant changes in local conditions
  • be referred to as an agent
  • Agents are implemented in end systems and nodes

38
Network Management Configuration
  • Network Management Application (NMA)
  • include an operator interface to allow an
    authorized user to manage the network
  • Respond to user commands
  • display information
  • issue commands to NMEs through the network
  • Communicate with and control NME in other nodes
  • Application-level network management protocol

39
Outline
  • Introduction
  • Network Management Requirement
  • SNMP Family
  • OSI Management Function Areas
  • Network Management System
  • Network Management Software Architecture
  • Distributed Network Management
  • Proxies

40
Network Management Software Architecture
  • Three categories
  • User presentation software
  • Network management software
  • Communications and database support software

41
Architectural Model of NMS
42
User Presentation Software
  • An interface in manager systems
  • monitor and control the network
  • An interface in agent systems
  • network testing and debugging
  • view or set parameters locally
  • Presentation tools
  • to organize, summarize, and simplify the
    information as much as possible to avoid
    information overload
  • graphical presentations
  • user interface should be the same at any node,
    regardless of vender

43
Network Management Software
  • Three-layer architecture
  • Network management application layer
  • Application element layer
  • Network management data transport service layer

44
Network Management Software (Cont)
  • Network management application
  • Provides services of interest to users
  • FCAPS
  • Each application covers a broad area of network
    management and should exhibit consistency over
    various types of configurations (LAN, WAN, ..)
  • Application elements
  • Implement primitive and general-purpose network
    management functions
  • generating alarms or summarizing data
  • Implement basic tools used by one or more network
    management applications
  • Developed based on software reuse

45
Network Management Data Transport Service
  • The module consists of
  • a NM protocol used to exchange management
    information among managers and agents
  • a service interface to the application elements
  • Provides very primitive functions (get, set and
    trap)

46
Communication Database Support Software
  • Network management software needs access to a
    local MIB, and to remote agents and managers
  • Local MIB at an agent contains
  • Information reflecting the configuration and
    behavior of this node
  • Parameters used to control the operation of this
    node
  • Local MIB at a manager contains
  • node-specific information
  • summary information about agents under control

47
Communication Database Support Software
  • MIB access module
  • Include basic file management software that
    enables access to the MIB
  • Convert local MIB format to a standardized form
    across the NMS
  • Communications protocol stack
  • OSI or TCP/IP stack
  • Support the network management protocol
  • Support communications among agents and managers

48
Outline
  • Introduction
  • Network Management Requirement
  • SNMP Family
  • OSI Management Function Areas
  • Network Management System
  • Network Management Software Architecture
  • Distributed Network Management
  • Proxies

49
Distributed Network Management
  • A centralized NMS enables the manager to maintain
    control over the entire configuration, balancing
    resource against needs and optimizing the overall
    utilization of resources
  • Why distributed network management?
  • the proliferation of low-cost, high power PCs
    workstations
  • the proliferation of departmental LANs
  • local control and optimization of distributed
    applications
  • distributed computing
  • Architecture of distributed network management
  • hierarchical architecture
  • department-level managers
  • manage downsized applications and PC LANs

50
Distributed Network Management
  • Benefits
  • network management traffic overhead is minimized
  • Offers greater scalability
  • eliminates single-point failure
  • Elements for hierarchical architecture
  • distributed management workstations
  • be given limited access for monitoring and
    control
  • manage the departmental resources
  • one central workstation (with a backup)
  • global access rights to manage all network
    resources
  • interact with less-enabled management stations

51
Distributed Network Management
  • Distributed management system architecture
  • management clients
  • Provide the user access to management services
    and information
  • Provide a graphical user interface
  • may access one or more management servers
  • management servers are the heart of the system
  • support a set of management applications and a
    MIB
  • store common management data models
  • route management information to applications and
    clients
  • managed network devices
  • Are managed directly by one or more management
    servers
  • through a vendor-specific element manager or proxy

52
Typical Distributed Management System Architecture
53
Outline
  • Introduction
  • Network Management Requirement
  • SNMP Family
  • OSI Management Function Areas
  • Network Management System
  • Network Management Software Architecture
  • Distributed Network Management
  • Proxies

54
Proxies
  • Why proxies?
  • older systems may not support network management
    standards
  • small systems are not suitable to be implemented
    full-blown NME
  • some components do not support agent software
  • Modems and multiplexers
  • Operations of proxies
  • translate requests and responses among managers
    and the target system
  • act on behalf of one or more other nodes

55
Proxy manager architecture
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