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Introduction to Network Management

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Introduction to Network Management Powered By Docstoc
					   Introduction to
Network Management
          Chu-Sing Yang

Department of Electrical Engineering
  National Cheng Kung University
       Outline
n Introduction
n Network Management Requirement
n SNMP Family
n OSI Management Function Areas
n Network Management System
n Network Management Software Architecture
n Distributed Network Management
n Proxies
       Outline
n Introduction
n Network Management Requirement
n SNMP Family
n OSI Management Function Areas
n Network Management System
n Network Management Software Architecture
n Distributed Network Management
n Proxies
            The Case for Management
                                                    Remote User

n   Typical problem
                                           Regional Offices
     ¨Remote    user arrives at regional
     office and experiences slow or no
     response from corporate web
     server
n   Where do you begin?
     ¨Where  is the problem?
     ¨What is the problem?
                                                              WWW Servers
     ¨What is the solution?

n   Without proper network
    management, these questions            Corp Network
    are difficult to answer
                 The Case for Management
                                                          Remote User

n   With proper management tools and
                                                 Regional Offices
    procedures in place, you may
    already have the answer
n   Consider some possibilities
      n   1. What configuration changes were
          made overnight?
      n   2. Have you received a device fault
          notification indicating the issue?
      n   3. Have you detected a security
                                                                    WWW Servers
          breach?
      n   4. Has your performance baseline
          predicted this behavior on an
          increasingly congested network link?
                                                 Corp Network
             Solving Problem Procedure
n   An accurate database of
    your network’s topology,                         Response Times   High Availability
    configuration, and
    performance
                                                                             Security
n   A solid understanding of the
    protocols and models used
                                    Predictability
    in communication between
    your management server and
    the managed devices
n   Methods and tools that allow
    you to interpret and act upon
    gathered information
          Introduction
n   Network Management System (NMS)
    ¨ Automatic versus human effort
    ¨ Increased network size
    ¨ Increased complexity
      n Heterogeneous equipment
      n Equipment from multiple vendors
       Outline
n Introduction
n Network Management Requirement
n SNMP Family
n OSI Management Function Areas
n Network Management System
n Network Management Software Architecture
n Distributed Network Management
n Proxies
          Network Management
          Requirements
n   Ease of use
n   Security features
n   Restoral capability
n   Ability to delete/add
n   Ability to monitor network availability
n   Traffic rerouting
n   Improved automation
n   User registration
n   Improved reporting
n   Ability to monitor response time
        Network Management
        Requirements
n Control corporate strategic assets
n Control complexity
n Improve service
n Balance various needs
n Reduce downtime
n Control cost
       Outline
n Introduction
n Network Management Requirement
n SNMP Family
n OSI Management Function Areas
n Network Management System
n Network Management Software Architecture
n Distributed Network Management
n Proxies
              Introduction to SNMP
n   Simple Network Management Protocol
    ¨ Provides     a tool
      n for multi-vender, interoperable network management
      n used across a broad spectrum of product types
          ¨    include end systems, bridges, switches, routers and
              telecommunications equipment
    ¨ TCP/IP     based
         Simple Network Management
         Protocol
n   A set of standards for network management
    ¨a  protocol
    ¨ a data base structure specification
    ¨ a set of data objects
          SNMP Family
n   SNMPv1
    ¨ Proposed   in 1989
n   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
          SNMP Family (cont.)
n   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
       RMON
n Remote network MONitoring
n a supplement to SNMP
n extend the capabilities of SNMP to include
  management of LANs as well as the devices
  attached to those networks
n RMON 1 issued in 1991
n RMON 2 issued in 1995
       Outline
n Introduction
n Network Management Requirement
n SNMP Family
n OSI Management Function Areas
n Network Management System
n Network Management Software Architecture
n Distributed Network Management
n Proxies
     OSI Management Functional
     Areas
n Fault management
n Configuration management
n Accounting management
n Performance management
n Security management
              Fault Management
n   The facilities that enable the detection, isolation, and
    correction of abnormal operation of the OSI environment
n   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
       n   Communication line is cut
       n   A crimp in the cable
       n   Certain errors may occur occasionally and are not normally considered
           to be faults
          Fault Management
n   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
                  User requirements for
                  Fault Management
n   Fast and reliable problem resolution
    ¨   Receive notification and correct the problem immediately
    ¨   Requires rapid and reliable fault detection and diagnostic management
    ¨   Provides fault tolerance
         n   Redundant components and alternate communication routes
         n   Fault management capability itself should be redundant
n   Keep informed of the network status
    ¨   Reassurance of correct network operation through mechanisms that use tests
        or analyze dumps, logs, alerts, or statistics
n   Problem tracking and control
    ¨   Ensure the problem is truly resolved and no new problems are introduced
n   Fault management should have minimal effect on network
    performance
             Configuration Management
n   Configuration management is concerned with
                 a network
    ¨ Initializing
    ¨ 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
                   Requirements for
                   Configuration Management
n   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
         n   End users want to inquire about the upcoming status of resources and their
             attributes before reconfiguration
    ¨   Generate configuration reports
         n   Periodic basis
         n   Response for a request
    ¨   Only authorized end users can manage and control network operation
        (software distribution and updating)
          Accounting Management
n   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
           Accounting Management
n   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
            Requirements for
            Accounting Management
n   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
n Generate accounting reports
n Provide the capability to verify end users’
  authorization to access and manipulate the
  information
             Performance Management
n   The facilities needed to evaluate
    ¨ the behavior of managed objects
    ¨ the effectiveness of communication activities

n   Functions of performance management
    ¨ Monitoring
       n   Tracks activities on the network
    ¨ Controlling
       n   Enables performance management to make
           adjustments to improve network performance
       Issues of Performance
       Management
n What is the level of capacity utilization?
n Is there excessive traffic?
n Has throughput been reduced to unacceptable
  levels?
n Are there bottlenecks?
n Is response time increasing?
              To Deal the Issues of PM
n   The network manager focus on some initial set of
    resources to be monitored in order to assess
    performance levels
    ¨ Appropriatemetrics and values with relevant network
      resources as indicators of different levels of performance
       n   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
             User Requirements for
             Performance Management
n   End users want to know
    ¨ the average and worst case response times
    ¨ the reliability of network services

n   Performance statistics can help managers
          manage and maintain large networks
    ¨ Plan,
    ¨ Recognize potential bottlenecks in advance
       n   balance or redistribute traffic load by changing routing
           tables
             Security Management
n   The facilities that address those aspects of OSI
    security essential to
    ¨ Operate  OSI network management correctly
    ¨ Protect managed objects
       n   network resources
       n   end user information
n   End users want to know
    ¨ the proper security policies are in force and effective
    ¨ the management of security facilities is itself secure
             Issues of Security
             Management
n   Managing information protection, and access control
    facilities
    ¨ Generating, distributing and storing encryption keys
    ¨ Passwords, authorization or access control information must be
      maintained and distributed
n   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
       Outline
n Introduction
n Network Management Requirement
n SNMP Family
n OSI Management Function Areas
n Network Management System
n Network Management Software Architecture
n Distributed Network Management
n Proxies
              Network Management
              Systems (NMS)
n   NMS is a collection of tools for network monitoring and
    control
    ¨ Designed    to view the entire network as a unified architecture
       n   addresses and labels assigned to each point
       n   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
       n   NMS software resides in the host computers and
           communications processors (bridges, routers)
            Network Management
            Systems
n   The active elements of the network provide regular
    feedback of status information to the network control
    center
n   NMS for single vendor equipment versus for multiple-
    vendor network
n   Two or more network control centers are used
    ¨ forhigh availability (backup)
    ¨ one center is idle or collecting statistics
    ¨ the other center is used for control
                      Network Management System
      Network control                       Server
      Host (manager)                       (agent)

          NMA
                                           NME     Appi
      NME      Appi
        Comm                                 Comm
          OS
                                               OS



                                 Router
Workstation
                                 (agent)
  (agent)                                    NMA = network management application

                                 NME         NME = network management entity
NME     Appi                                 Appl = application
                                             Comm = communications software
                                Comm
 Comm                                        OS = Operating system

   OS                             OS
                Network Management
                Configuration
n   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)
         n Transmit collect statistics to manager
         n Change a parameters (a timer in a transport protocol)
         n Provide status information
         n 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
            Network Management
            Configuration
n   Network Management Application (NMA)
    ¨ include an operator interface to allow an
      authorized user to manage the network
    ¨ Respond to user commands
      n display information
      n issue commands to NMEs through the network

    ¨ Communicate      with and control NME in other
     nodes
      n   Application-level network management protocol
          Outline
n   Introduction
n   Network Management Requirement
n   SNMP Family
n   OSI Management Function Areas
n   Network Management System
n   Network Management Software Architecture
n   Distributed Network Management
n   Proxies
             Network Management
             Software Architecture
n   Three categories
    ¨ Userpresentation software
    ¨ Network management software
    ¨ Communications and database support software
Architectural Model of NMS
           User Presentation Software
n   An interface in manager systems
    ¨ monitor   and control the network
n   An interface in agent systems
    ¨ network  testing and debugging
    ¨ view or set parameters locally
n   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
          Network Management
          Software
n   Three-layer architecture
    ¨ Network  management application layer
    ¨ Application element layer
    ¨ Network management data transport service layer
               Network Management
               Software (Cont’)
n   Network management application
    ¨ Provides     services of interest to users
       n   FCAPS
    ¨ Each  application covers a broad area of network management
      and should exhibit consistency over various types of
      configurations (LAN, WAN, ..)
n   Application elements
    ¨ Implement     primitive and general-purpose network management
      functions
       n   generating alarms or summarizing data
    ¨ Implement basic tools used by one or more network
      management applications
    ¨ Developed based on software reuse
               Network Management Data
               Transport Service
n   The module consists of
    ¨a  NM protocol used to exchange management
      information among managers and agents
    ¨ a service interface to the application elements
       n   Provides very primitive functions (get, set and trap)
          Communication & Database
          Support Software
n   Network management software needs access to a
    local MIB, and to remote agents and managers
n   Local MIB at an agent contains
    ¨ Information   reflecting the configuration and behavior of this
      node
    ¨ Parameters used to control the operation of this node

n   Local MIB at a manager contains
    ¨ node-specificinformation
    ¨ summary information about agents under control
            Communication & Database
            Support Software
n   MIB access module
    ¨ Includebasic file management software that enables
      access to the MIB
    ¨ Convert local MIB format to a standardized form across the
      NMS
n   Communications protocol stack
    ¨ OSIor TCP/IP stack
    ¨ Support the network management protocol
    ¨ Support communications among agents and managers
       Outline
n Introduction
n Network Management Requirement
n SNMP Family
n OSI Management Function Areas
n Network Management System
n Network Management Software Architecture
n Distributed Network Management
n Proxies
              Distributed Network
              Management
n   A centralized NMS enables the manager to maintain control over
    the entire configuration, balancing resource against needs and
    optimizing the overall utilization of resources
n   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
n   Architecture of distributed network management
    ¨   hierarchical architecture
    ¨   department-level managers
          n manage downsized applications and PC LANs
             Distributed Network
             Management
n   Benefits
    ¨ network  management traffic overhead is minimized
    ¨ Offers greater scalability
    ¨ eliminates single-point failure
n   Elements for hierarchical architecture
    ¨ distributed   management workstations
       n   be given limited access for monitoring and control
       n   manage the departmental resources
    ¨ one   central workstation (with a backup)
       n   global access rights to manage all network resources
       n   interact with less-enabled management stations
             Distributed Network
             Management
n   Distributed management system architecture
    ¨ management      clients
       n   Provide the user access to management services and
           information
       n   Provide a graphical user interface
       n   may access one or more management servers
    ¨ management      servers are the heart of the system
       n   support a set of management applications and a MIB
       n   store common management data models
       n   route management information to applications and clients
    ¨ managed     network devices
       n   Are managed directly by one or more management servers
       n   through a vendor-specific element manager or proxy
      Typical Distributed Management
           System Architecture
                     Management clients ( PCs, workstations )



                                         Network


Management server                              Management server
    Management                                     Management          MIB
     application
                            MIB                     application



                                    Network

                               Element              Element
                               manager              manager




     Network resources ( servers, routers, hosts ) with management agents
       Outline
n Introduction
n Network Management Requirement
n SNMP Family
n OSI Management Function Areas
n Network Management System
n Network Management Software Architecture
n Distributed Network Management
n Proxies
              Proxies
n   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
       n   Modems and multiplexers
n   Operations of proxies
    ¨ translate requests and responses among managers and
      the target system
    ¨ act on behalf of one or more other nodes
            Proxy manager architecture
Management                                                   Management
                                 Proxy manager
application                                                   application


  Client                  Server         Client proxy           Client
   stub                    stub              stub                stub

 Protocol                Protocol          Protocol            Protocol
  stack                   stack             stack                stack



           Standard operations               Proprietary operations and
            and event reports                       event reports

				
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posted:4/13/2014
language:English
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