LAN/WAN Optimization Techniques Chp.1~Chp.4

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LAN/WAN Optimization TechniquesChp.1Chp.4

• Harrell J. Van Norman
• Presented by Shaun Chang

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Outline

• Networks
• Local-Area Networks (LANs)
• Wide-Area Networks (WANs)
• Network Design
• Network Engineering Process
• Network Design Tools

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Networks

• LANs
• Short-distance networks (less than 1 mile)
• Data transfer between computers devices
• MANs
• Medium-distance networks (1 to 50 miles)
• Voice, video, data transfer
• WANs
• Long-distance networks
• Voice, data, video transfer between local,
  metropolitan, campus, premise networks

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LANs

• Standards
• Ethernet
• Token Bus
• Token Ring
• FDDI

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Internetworking

• Communications Hardware
• Bridges
• Brouters
• Routers
• Gateways

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WAN Access

• Communications Hardware
• Modems
• Multiplexers (FDM, TDM, STDM)
• Channel Banks
• CSUs, DSUs

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WAN Transport

• Private
• Twisted Pair
• T1
• Fractional T-1
• T3
• Fractional T-3
• DDS
• NHD
• SONET
• Satellite
• Microwave

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WAN Transport

• Public
• Circuit Switching
• dial-up lines
• ISDN
• Packet Switching
• X.25
• Frame Relay
• ATM
• SMDS

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Outline

• Networks
• Network Design
• LAN Design
• WAN Design
• Network Engineering Process
• Network Design Tools

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Network Design

• Cost-performance trade-offs
• Prices of the hardware
• Reliability
• Response time
• Availability
• serviceability

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LAN Design

• Media choices
• Twisted-pair
• Coaxial cable
• Fiber optics
• Wireless systems
• Media access protocol
• Token ring, token bus, Ethernet CSMA/CD
• Cabling strategies
• Intelligent hub wiring
• Distributed cabling system
• Centralized proprietary cabling

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LAN simulation tools

• LAN simulation tools provide measures of
• Utilization
• Conflicts
• Delays
• Response times
• Identify cost-performance-reliability trade-offs
• Find the bottlenecks in network performance

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WAN Design

• Designs based on various routing, multiplexing,
  and bridging approaches
• More complex
• Tariff data changes frequently
• Many new service offerings
• Numerous networking options

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Outline

• Networks
• Network Design
• Network Engineering Process
• Network Awareness
• Network Design
• Network Management
• Network Design Tools

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Network Engineering Process
Network awareness
Network design
Network management
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Network awareness

• Technology assessment
• Current traffic
• Equipment inventory
• Forecasted growth
• Operational evaluation criteria

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Network design

• Network design tool
• Cost/performance breakeven analysis
• Equipment acquisition

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Network management

• Configuration
• Fault management
• Performance management
• Maintenance and administration

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Total network engineering decision approach
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Outline

• Networks
• Network Design
• Network Engineering Process
• Network Design Tools
• Simulation
• Analytic Models
• Benefits
• Limitations

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Experimental measurements Prototyping

• Quality measurement monitoring tools
• Cumbersome
• Expensive
• Time-consuming
• Relatively inflexible

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Simulation

• Is driven by a stream of pseudorandom numbers
• Time-consuming, but more accurate
• Overcome problems caused by simplifying
  assumptions

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Analytic Models

• Require a high degree of abstraction
• Difficult to evaluate the performance of a
  complex communication system
• Queuing theory plays a major role
• Calculate answers in near real-time

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Benefits

• Minimize Costs
• Reduce Design Time
• 1000-devices network designed in about one hour
• Ensure Proper Performance
• Avoid costly overbuilding and rebuilding
• Assist Design Evaluation
• Evaluate vendor claims and networking strategies
• Verify performance predictions

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Benefits--Minimize Costs

• Low-speed access WAN lines are consolidated
• The best transmission services are obtained
• Unnecessary facilities are eliminated
• Communications equipment configurations are
  optimized
• Save 20 to 45 percent

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Overbuilding and Rebuilding
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Limitations

• Cost 5000-100,000 for WAN optimization design
  tools and up to 10,000 for LAN
• Capable and knowledgeable network designers are
  required
• Input parameters of traffic volumes, message
  sizes, etc are not good enough
• Network design is a process of iterative design
  and refinement

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Feedback control mechanisms
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Network Awareness Decision Approach

• Needs Analysis
• Technology assessment
• Traffic and equipment inventory
• Growth forecast
• Operational evaluation criteria

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Overall Gain of a SFG

• The general problem in network analysis of
  finding the relation between response (output) to
  stimulus (input) signals is equivalent to finding
  the overall gain of that network.
• In SFG analysis, this can be done by two general
  methods
• Node Absorption (Elimination) method.
• In this method, the overall gain of SFG from a
  source node to a sink node may be obtained by
  eliminating the intermediate nodes.
• Mason's rule method.

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Mason's Rule
Mason's rule is a general gain formula can be
used to determine the transfer functions
directly. (i.e., relates the output to the input
for a SFG. )
Thus the general formula for any SFG is given by

• Where,
• Pi the total gains of the ith forward path
• D 1 - ( ? of all individual loop gains) ( ?
  of loop gains of all possible non-touching loops
  taken two at a time) - ( ? of loop gains of all
  possible non-touching loops taken three at a
  time)
• Di the value of D evaluated with all gain
  loops touching Pi are eliminated.
• Notice In case, all loops are touching with
  forward paths (Pi ) , ? Di 1

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Touching loops Loops with one or more nodes in
common are called touching. A loop and a path
are touching when they have a common
node. Non-touching loops Loops that do not have
any nodes in common Non-touching loop gain The
product of loop gains from non-touching loops.
Example Find C/R for the attached SFG. Forward
Path gain (Only one path, So, i 1) ? P1
G1.G2.G3.G4.G5 . (1) Loop gains L1
G2.H1 L2 G4.H2 L3 G7.H4 L4G2.G3.G4.G5.G6.G6.G7.
G8 Non-touching loops taken two at a time L1L2
G2.H1.G4.H2 L1L3 G2.H1.G7.H4 L2L3
G4.H2.G7.H4 Non-touching loops taken three at a
time L1,L2L3 G2.H1.G4.H2.G7.H4
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sum of all individual loop gains
According to Masons rule
sum of gain products of all possible non-touching
loops taken two at a time
? 1 - (G2.H1 G4.H2 G7.H4
G2.G3.G4.G5.G6.G7) G2.H1.G4.H2
G2.H1.G7.H4 G4.H2.G7.H4 G2.H1.G4.H2.G7.H4


. . (2) Then, we form ?i by
eliminating from ? the loop gains that touch the
forward path (Pi). ? ?1 ? - ?loop gains
touching the forward path (Pi).
sum of gain products of all possible non-touching
loops taken three at a time

• ?1 1 - G7.H4 ...
  (3)
• Now Substituting equations (1) , (2) (3) into
  the Masons Rule as

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Using of Mason's Rule to solve SFG
The following procedure is used to solve any SFG
using Mason's rule. 1) Identify the no. of
forward paths and their gains (Pi). 2) Identify
the number of the loops and determine their gains
(Lj). 3) Identify the non-touching loops taken
two at a time, a three at a time,
etc. 4) Determine D . 5) Determine ?i . 6)
Substitute all of the above information in the
Mason's formula.