LAN/WAN Optimization Techniques

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LAN/WAN Optimization Techniques
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Agenda

• Current Traffic
• Equipment Inventory and Forecasted Growth
• Operational Evaluation Criteria
• Network Design Decision Approach

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Current Traffic

• Loads
• Traffic classes
• Traffic response times
• Transaction types
• Protocol overhead

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Loads

• Traffic Loads the volume of data communication
  traffic
• -data
• -data transmission overhead

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Loads (cont.)

• Traffic Load is generally calculated by
  analytically-based NDTs on the following
  parameters
• -message definition
• -message characteristics
• - traffic load is required by NDTs for each
  location on the network

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Loads (cont.)

• NDTs calculate traffic load based on standard
  deviations from average values account for these
  peaks and valleys in traffic volume
• -peak
• -normal
• -valley

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Traffic classes

• Traffic loads should be broken down into these
  types of traffic classes for message prioritizing
• -real time
• -interactive
• -file transfer

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Traffic response times

• Average transaction response times
• RTICPUO

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Traffic response times (cont.)

• Polling environments
• I or O TWS

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Traffic response times (cont.)

• Service times
• Transmission time is the time needed to send the
  entire message (overhead and text) down the line

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Traffic response times (cont.)

• Connection delay is the time needed by the
  front-end processor to establish a connection
  with terminal, including modem turnarounds
• Polling delay is attributed to multipoint lines
  in which terminals must wait their turn before
  being polled by the front-end processor

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Traffic response times (cont.)

• Arrival rates number of messages that arrive at
  all the terminals on the line
• Line utilization (U)
• Waiting time (W)
• P-K formula

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Transaction types

• The most appropriate approach calculates response
  time based on the varied mixture of transaction
  types that each location supports

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Protocol overhead

• Control messages are necessary in both poll and
  select scenarios to inquire if the terminal has
  data to send or is ready to receive
• -polling mode
• -select mode
• -control message requires data rates, line
  sizes
• -protocol overhead

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Protocol overhead (cont.)
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agenda

• Current Traffic
• Equipment Inventory and Forecasted Growth
• Operational Evaluation Criteria
• Network Design Decision Approach

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Equipment Inventory and Forecasted Growth

• Equipment inventory
• Inventory
• forecasting

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Equipment inventory

• Without an accurate awareness of the
  communications network, design and analysis is
  impractical
• Equipment inventories and growth forecasts
  develop an understanding of the network that is
  fundamental to any engineering process

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Inventory

• An essential of network design is identifying
  communications equipment
• Physical resources
• -compatibility
• -meet the needs of the networks users

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Inventory (cont.)

• Location-in order to identifying communication
  equipment types, locations of all devices must
  be specified
• -equipment types and locations are known,
  fixed, unalterable
• -equipment types and location possibilities are
  known
• - equipment locations determination
  accommodates an unlimited selection of
  possibilities
• Types-reference 6.4 communication hardware

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forecasting

• Network engineers need to consider forecasted
  growth when conducting design exercises
• Forecasting growth is critical during network
  design
• Once current and future applications of data
  communications have been identified, engineer
  must forecast growth trends in usage over the
  planning period

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Forecasting (cont.)

• Forecasting based on trends is the safest method
  of determining the future of data communications
  traffic demands
• -trend lines are independent of business
  activity
• -outside affects are suspected
• -trend lines generally follow business activity

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Forecasting (cont.)

• trend lines are not directly dependent on
  business activity, survey must be conducted in an
  attempt to explain the independence
• Purpose of surveys is to establish the aspects of
  business activity on which the data
  communications usage will depend

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agenda

• Current Traffic
• Equipment Inventory and Forecasted Growth
• Operational Evaluation Criteria
• Network Design Decision Approach

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Operational Evaluation Criteria

• Performance
• Availability
• Reliability
• Cost
• security

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Performance

• Evaluate what performance criteria are necessary
  for acceptable operational characteristics of the
  network
• -response time
• -throughput
• -utilization
• -blocking rate

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Availability

• Availability
• -reliability (MTBF)
• -serviceability (MTTR)
• Serial-overall system availability

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Availability (cont.)

• Parallel-overall system availability

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Reliability

• Mean time between failures

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Cost

• Line cost recurring monthly service charges
  nonrecurring one-time installation costs
• Equipment cost
• Software cost

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security

• The most effective security measures involve a
  variety of barriers of different types and
  different places

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agenda

• Current Traffic
• Equipment Inventory and Forecasted Growth
• Operational Evaluation Criteria
• Network Design Decision Approach

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Network Design Decision Approach

• Network design tool utilization
• Cost-performance break-even analysis
• Equipment acquisition

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Network design tool utilization

• This step involved selection of the most
  appropriate design technique, acquisition of an
  NDT, development of a network model, and analysis
  of the model
• --most critical step of the entire network
  engineering process

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Network design phase
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Cost-performance break-even analysis

• This step involved generating and evaluating
  alternative network designs
• What-if questions are used to evaluate various
  alternative configurations
• -proposals for adding / deleting resources
• -redesign application to improve the
  performance
• -modeling different routing strategies

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Cost-performance break-even analysis (cont.)

• Each of the various alternative configurations
  will have associated costs and performance levels
• Trade-off between cost/performance

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Equipment acquisition

• This step involves obtaining the necessary
  equipment as specified in the optimal optimized
  network design
• Once this step is complete, an optimized
• implementable design is available as input
  into the next phase network management