CIT 443: Enterprise Network Management

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CIT 443 Enterprise Network Management

• Fault Management

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Fault?

• An event that causes adverse, unintended, or
  non-specification operating conditions in or on
  an enterprise network system
• May be masked by automatic error correction
  routines
• May be perceived initially as performance
  problems
• Incidents may become an indicator of more serious
  issues with increased frequency

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Classification of Faults
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Fault Management

• The process of identifying, locating,
  documenting, resolving adverse, unintended, or
  non-specification operating conditions of
  enterprise network systems
• Includes the necessary policies, processes, /or
  procedures for all steps as well

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Benefits of Fault Management

• Reduce down-time
• Reduce the need for fire-fighting
• Allow more time for other management tasks

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Elements of Fault Management

• System Monitoring
• Alarm Processing
• Fault Resolution

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System Monitoring Alarm Processing 3 Relevant
Protocols

• SNMP (v3) Defines the format of packets
  exchanged between a manager and an agent. It
  reads and changes the status (values) of objects
  (variables) in SNMP packets. (Forouzan, p. 625)
• MIB (v2) Creates a collection of named objects,
  their types, and their relationships to each
  other in an entity to be managed. (Forouzan, p.
  625)
• SMI (v2) A guideline for SNMP that emphasizes
  three attributes to handle an object
• Name
• Data Type
• Encoding Method

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SNMP Managers and Agents

• Framework for managing devices in an internetwork
  using the TCP/IP protocol suite.
• Manager Host that runs the SNMP client program
• Agent Host (router, switch, etc.) that runs the
  SNMP server
• Agent maintains information in a database to be
  queried and/or modified by the manager
• Agent can also contribute to the management
  process by sending unsolicited messages to the
  manager (traps) to notify of system events

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SNMP Three Management Functions

• Manager can query an agent for information
• Manager can force an agent to perform a task
• Agent can contribute to management process (traps)

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Structure of Management Info

• Abstract Syntax Notation (ASN.1) is used to
  access information contained within the MIB
  stucture.
• A notation system that identifies data structures
  for reliable encoding, transmission, and decoding
  of messages.
• Nearly all entities managed by SNMP have an
  object ID that starts with 1.3.6.1.2.1
• ISO.org.dod.internet.mgmt.mib-2

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Fault Resolution Process

• Identify the fault
• What are the fault symptoms?
• What could be the problem?
• Isolate the fault
• Prioritize the fault
• Correct the fault (if possible)
• Fault Reporting

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Identify a Fault - Collect Information

• Log Network Events
• Through the use of SNMP Traps, etc.
• Which device(s) originated the events?
• Watchdog Timers
• Reset with the completion of a given task
• Generate a trap when timer expires and the task
  is not complete
• Polling
• Periodic monitoring of network activity
• Polled data is often logged to a server
• Useful in trend analysis and resolving
  intermittent faults
• Useful for resolving problems after the fact
• Polling uses bandwidth shorter polling
  intervals require more bandwidth

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Isolate the Fault

• Look Beyond the Symptoms
• Use a Fault Isolation Methodology
• Top Down
• Bottom Up
• Intermittent Problems are Difficult!
• Why?
• Attempt to take a snap-shot of network at time of
  service interruption
• Take note of recurrence time
• Attempt to correlate data What is the same?
• Determine if part of a Common Cause Fault
  (Failure) Group?
• Root Cause Analysis

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Isolate the Fault
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Prioritize Faults

• Not all faults are of the same priority
• Determine which faults to take immediate action
  on and which to defer
• Some prioritization can be performed at the help
  desk level
• Divide and conquer

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Prioritize Faults
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Correct the Fault

• Repair, Restore, Replace, then Reevaluate
• Remember, faults can be caused by just about
  anything in the networkincluding users.
• Fixing the underlying fault may require a change
  in the policies of how users interact with
  network systems

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Fault Reporting

• Symptoms
• Effect on Network Operations
• Cause
• Resolution
• Update Documentation
• What is the purpose of reporting?

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Reporting/Documentation

• MTTF
• MTBF
• Failure Rate
• MTTR

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Fault Management Network Entities

• PBX
• Hubs
• Routers
• Switches
• Servers
• Workstations
• Firewalls
• Intrusion Detection/Prevention Systems
• Wireless Access Points
• Power Management Systems
• Network SCADA systems
• Temperature Management Systems (HVAC)
• Home Appliances?
• Others?

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Industry Trends

• Enterprise Network Management is a key initiative
  for large companies
• All encompassing Manage every part of the
  enterprise network
• Automate Correlation
• 80 of time is spent trying to isolate
  determine the fault (root cause analysis)
• Notify a manager or engineer of what to fix
• Automate Fault Resolution - Device manager fixes
  problems local to the box or network comprised of
  the same components

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Topics for Further Investigation

• Technologies for Automating Fault Diagnosis
• Methods for Automated Fault Resolution
• Evolution of Protocols for Fault Notification and
  Trapping
• Fault Management System Architectures
• Enterprise Network Management Best Practices and
  Lessons Learned
• Corporate Implementations of Enterprise Network
  Management Systems
• Current Issues with Enterprise Network Management
• Enterprise Network Management of Wireless
  Networks
• Enterprise Network Management of Converged
  Networks with Differentiated Services

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Questions?