Transcript Chapter 15 - Wright State University

CEG 2400 FALL 2012
Chapter 15
Network Management
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Fundamentals of Network Management
• Fundamentals of Network management
– Assess, monitor, and maintain all network aspects
– The amount you manage differs according to
network’s size and importance
– Several network management disciplines and they all
share same goals
• Enhance efficiency and performance
• Prevent costly downtime and loss
– Predict problems before they occur
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Documentation
• Network features to document
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Physical topology
Access method
Protocols
Devices
Operating systems
Applications
Configurations
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Documentation
• Network diagrams
– Graphical representations of network’s devices,
connections
– Provide broad snapshot of network’s physical or
logical topology
• Wiring schematic
– Graphical representation of network’s wired
infrastructure
– Detailed form
• Includes every wire connecting network devices
– Or Less detailed form
• Single line represents group of wires connecting
several clients to a switch
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Network diagram using Cisco symbols
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Wiring schematic
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Measurements - Baseline
• Baseline - network’s current operation state
• Gathering baseline data
– Many Software applications
• Some freeware, some expensive
• Compare future and past performance
– Critical network, user functions
– More data provides more accuracy
• Forecasting network traffic patterns
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Baseline of daily network traffic
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Policies, Procedures, and Regulations
• Rules limit chaos, confusion, downtime
• State and federal regulations
– CALEA (Communications Assistance for Law
Enforcement Act)
• Telecommunications carriers, equipment
manufacturers must provide for surveillance capabilities
– HIPAA (Health Insurance Portability and
Accountability Act)
• Protect medical records security and privacy
• Many policies and procedures
– Not laws
– Best practices to prevent network problems
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Fault and Performance Management
• Assess network’s status on an ongoing basis
• Performance management
– Monitor links and devices’ ability to keep up with
demand
• Fault management
– Detection and signaling of device, links, or
component faults
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Network Management Systems
• Enterprise-wide network management systems
– Accomplish fault and performance
management/monitoring
– Polling
• Collecting data from multiple networked devices at
regular intervals
– Agents
• Collects information about device’s operation
• Provides information to network management
application
• Various aspects of a device can be managed
– Processor, memory, hard disk, NIC, etc.
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Network Management Software
• Agent-based with network management application can use
– MIB (Management Information Base)
• Contains managed devices definition, data
– SNMP (Simple Network Management Protocol)
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Used to communicate managed device information
Part of TCP/IP suite
SNMPv3: most secure version of the protocol
SNMPv2 still widely used
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Network management architecture
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System and Event Logs
Windows
• Log
– File that contains recorded conditions recognized by
operating system
• Event log
– Windows-based computer log containing monitored
device information
• Event Viewer - used to view log information in
Windows
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System and Event Logs
Linux or UNIX
• Syslog function
– Standard for generating, storing, and processing
messages about events on Linux or UNIX
– Data written to a system log
• Using logs for fault management
– Logs keep history
– Information collected does not always point to
problem
– Logs must be monitored for errors
– There are applications used for viewing, filtering
information
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Traffic Shaping
• Traffic shaping
– Manage type and amount of traffic traversing network
– Goals
• Assure timely delivery of most important traffic
• Offer best possible performance for all users
– Not without controversy
• Techniques
– Traffic policing
• Limit traffic volume flowing in and out of interface
during specified time period by importance
• Limit throughput rate for an interface
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Traffic volume before and after applying limits
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Traffic Shaping
• Traffic prioritization technique
– Treating more important traffic preferentially
– Prioritization based on characteristics
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Protocol
IP address
User group
Service or application
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Caching
• Caching
– Local storage of frequently needed files
– Allows quick access
• Web caching
– Web pages stored locally
• On host or network, and then delivered to client
• ISP cache engine
– Network device devoted to storage, frequently
requested file delivery
– Saves money; lowers WAN traffic
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Asset Management
• Identifying and tracking hardware and software
• First step
– Inventory each network node
• Benefits
– Simplifies maintaining and upgrading network
– Provides information about hardware and software
costs and benefits
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Change Management
• Managing change while maintaining network
efficiency and availability
• Common software and hardware changes range
from installing patches to replacing network
backbone
• Several ways to approach changes
– Software Changes
– Hardware and Physical Plant Changes
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Software Changes
• Software upgrades change
• Application patches and upgrades
• Need to know how to reverse a software upgrade
– Software change may create unexpected problems
– Be prepared to reverse an upgrade
• General steps
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Determine whether patch or upgrade is necessary
Research change purpose, compatibility, and effects
Determine whether changes should apply to all users
Determine distribution method
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Software Changes
• General steps (cont’d.)
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Notify appropriate personnel of intent to change
Back up current system
Prevent users from accessing system during change
Implement the change
Test system fully
Re-enable access to the system
Inform personnel that change is complete
Record change in the change management system
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Software Changes
• NOS (Network Operating System) upgrades change
– Most critical upgrade type
– Involves significant and potentially drastic changes to
the way servers and clients operate
– Upgrade requires forethought and rigorous testing
– Create a project plan
– Complex, far-reaching change
– Ensure appropriate budget, resources, and time
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Hardware and Physical Plant Changes
• Required when network component fails or
malfunctions
• More commonly performed as an upgrade
– Increase capacity, improve performance, and add
network functionality
• Face same issues as software changes
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Hardware and Physical Plant Changes
• Adding or upgrading equipment
– Take time to research, evaluate, and test unfamiliar
equipment
– If consistency is a concern
• Purchase as much hardware as possible in single order
• Purchase from same vendor
– Different preparation and implementation
requirements for each device type
– Devices that are most disruptive and complex to add
or upgrade are the most difficult to remove or undo
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Hardware and Physical Plant Changes
• Cabling upgrades
– Can require significant implementation planning
• Depending on network size
– Troubleshooting cabling problems
• Easier with current and accurate wiring schematics
– Carefully document existing cable before making
upgrades
• Ensures future upgrades go smoothly
– Consider upgrading in phases
– Carefully document after upgrade
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Hardware and Physical Plant Changes
• Cabling upgrades (cont’d.)
– Weigh upgrade importance against disruption
potential
– Organizations with very small networks
• Upgrade own network cabling
– Larger organizations
• Rely on contractors
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Hardware and Physical Plant Changes
• Backbone upgrades
– Most comprehensive and complex upgrade
– Backbone represents main data conduit
– Requirements
• Extensive planning and personnel efforts
– Upgrading entire backbone changes the whole
network
• Reversing hardware changes
– Provide way to reverse hardware upgrade
• Reinstall old hardware, If faulty: reinstall not possible
– Keep old components safe and nearby
• Refer to it for information
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Summary
• Network management
– Assessing, monitoring, and maintaining network
devices and connections
• Configuration management
– Software and hardware configuration documentation
• Network management applications use SNMP to
communicate with managed devices
• System logs and event logs record conditions
• Software and hardware upgrades require planning
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End of Chapter 15
Questions
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