Chapter 19: Network Management

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Chapter 19Network Management

• Business Data Communications, 4e

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Network Management Requirements

• Fault Management
• Accounting Management
• Configuration and Name Management
• Performance Management
• Security Management

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Fault Management

• A fault is an abnormal condition that requires
  management attention (or action) to repair
• Fault is usually indicated by failure to operate
  correctly or by excessive errors
• Users expect quick and reliable resolution

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Accounting Management

• Reasons for accounting management
• Internal chargebacks on network use
• User(s) may be abusing access privileges and
  burdening the network at the expense of other
  users
• Users may be making inefficient use of the
  network
• The network manager is in a better position to
  plan for network growth if user activity is known
  in sufficient detail.

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Configuration Management

• Concerned with
• initializing a network and grace-fully 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

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Performance Management

• Issues of concern to the network manager include
• 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?
• Network managers need performance statistics to
  help them plan, manage, and maintain large
  networks

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Security Management

• Concerned with
• generating, distributing, and storing encryption
  keys
• monitoring and controlling access to networks
• access to all or part of the network management
  information
• collection, storage, and examination of audit
  records and security logs

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Network Management Systems

• Collection of tools for network monitoring and
  control, integrated in these ways
• A single user-friendly operator interface for
  performing most or all network management tasks
• A minimal amount of separate equipment
• consists of incremental hardware and software
  additions implemented among existing network
  components

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Network Management System Architecture
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Components of the NMS

• All nodes run the Network Management Entity (NME)
  software
• Network control host or manager runs the Network
  Management Application (NMA)
• Other nodes are considered agents

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Network Monitoring Systems
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Simple Network Management Protocol (SNMP)

• Designed in the mid-1980's as an answer to the
  communication problems between different types of
  networks.
• Consists of a simply composed set of network
  communication specifications that cover all the
  basics of network management in a method that
  poses little stress on an existing network.
• Each SNMP device (router, gateway, server) has an
  agent that collects information about itself and
  the message it processes, and stores that
  information in a database called the management
  information base (MIB) .

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Role of SNMP

• Transmission of a message
• Receipt of a message
• Variable bindings

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SNMP

• The network management software has access to
  these MIBs. A network manager can use this
  software to send control messages to individual
  devices or groups of devices asking them to
  report the information stored in their MIB.
• Network information is exchanged through the
  messages called protocol data units (PDU's). The
  PDU can be looked at as an object that contains
  variables that have both titles and values.

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SNMP

• Five types of PDU's employed to monitor a
  network
• two deal with reading terminal data,
• two deal with setting terminal data,
• and one, the trap, is used for monitoring network
  events such as terminal start-ups or shut-downs.
• To see if a terminal is attached to the network,
  a user uses SNMP to send out a read PDU to that
  terminal.
• If the terminal was attached to the network, the
  user would receive back the PDU, it's value being
  "yes, the terminal is attached".
• If the terminal was shut off, the user would
  receive a packet informing them of the shutdown.

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SNMPv2

• Released in 1992, revised in 1996
• Addressed functional deficiencies in SNMP
• Accommodates decentralized network management
• Improves efficiency of data transfer

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SNMPv3

• Released in 1998, addressed security deficiencies
  in SNMP and SNMPv2
• Does not provide a complete SNMP capability
  defines an overall SNMP architecture and a set of
  security capabilities for use with SNMPv2
• Provides three important services
  authentication, privacy, and access control

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Common Management Interface Protocol (CMIP)

• CMIP was designed to build on SNMP by making up
  for SNMP's shortcomings and becoming a bigger,
  more detailed network manager. Its basic design
  is similar to SNMP, whereby PDU's are employed as
  variables to monitor a network. CMIP however
  contains 11 types of PDU's.
• The biggest feature of the CMIP protocol is that
  its variables not only relay information to and
  from the terminal (as in SNMP), but they can also
  be used to perform tasks that would be impossible
  under SNMP.
• Problem Too wonderful to be implemented.

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Remote Monitoring (RMON)

• A standard that provides managers with real-time
  network and application data for LANs.
• The major benefits of RMON
• Powerful Monitoring and Analysis
• Historical Trending of the Local Segment
• Traditional Protocol Decode Functions
• Centralized Monitoring of Remote Sites
• Multi-vendor Interoperability
• Event Creation on Reaching Predefined Thresholds
• RMON is supported by SNMP
• Newer version is RMON2

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How RMON Works

• Enables MIB information to be stored on the
  device itself or on distributed RMON probes that
  store MIB information closer to the devices that
  generate it.
• No transmission from MIB to the central server
  until requesting the data.
• RMON reduces network traffic.

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RMON and RMON2
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Multi-Router Traffic Grapher (MRTG)

• MRTG is a tool to monitor the traffic load on
  network-links.
• MRTG generates HTML pages containing GIF images
  which provide a LIVE visual representation of
  this traffic.
• MRTG is based on Perl and C and works under UNIX
  and Windows NT.
• MRTG is being successfully used on many sites
  around the net. (MRTG-Site-Map).

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LANWatch32

• Precision Guesswork's LANWatch32 Network Analyzer
  for Windows 95/NT is a software solution
  targeting the complex task of network analysis.
• Decodes over 60 network protocols, including
  TCP, UDP, IP, IPv6, NFS, NFS (version 3),
  NetWare, SNA, AppleTalk, VINES, ARP, and NetBIOS.
• Media Supported
• Ethernet (802.3) 10 Mb/100 Mb
• Token Ring (802.5)
• Serial Line

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Demonstration

• http//www.rad.com/networks/1998/snmp/snmp.html