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

LAN/WAN Optimization Techniques Chp.1~Chp.4. Harrell J. Van Norman Presented by Shaun Chang. Outline. Networks Local-Area Networks (LANs) Wide-Area Networks (WANs) Network Design Network Engineering Process Network Design Tools. Networks. LANs Short-distance networks (less than 1 mile)

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

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  1. LAN/WAN Optimization TechniquesChp.1~Chp.4 Harrell J. Van Norman Presented by Shaun Chang

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

  3. 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

  4. LANs • Standards • Ethernet • Token Bus • Token Ring • FDDI

  5. Internetworking • Communications Hardware • Bridges • Brouters • Routers • Gateways

  6. WAN Access • Communications Hardware • Modems • Multiplexers (FDM, TDM, STDM) • Channel Banks • CSUs, DSUs

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

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

  9. Outline • Networks • Network Design • LAN Design • WAN Design • Network Engineering Process • Network Design Tools

  10. Network Design • Cost-performance trade-offs • Prices of the hardware • Reliability • Response time • Availability • serviceability

  11. 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

  12. 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

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

  14. Outline • Networks • Network Design • Network Engineering Process • Network Awareness • Network Design • Network Management • Network Design Tools

  15. Network Engineering Process Network awareness Network design Network management

  16. Network awareness • Technology assessment • Current traffic • Equipment inventory • Forecasted growth • Operational evaluation criteria

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

  18. Network management • Configuration • Fault management • Performance management • Maintenance and administration

  19. Total network engineering decision approach

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

  21. Experimental measurements Prototyping • Quality measurement & monitoring tools • Cumbersome • Expensive • Time-consuming • Relatively inflexible

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

  23. 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

  24. 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

  25. 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

  26. Overbuilding and Rebuilding

  27. 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

  28. Feedback control mechanisms

  29. 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.

  30. 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 Piare eliminated. Notice: In case, all loops are touching with forward paths (Pi) , Di = 1

  31. V5(s) 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 L4:G2.G3.G4.G5.G6.G6.G7.G8 Non-touching loops taken two at a time: L1&L2 : G2.H1.G4.H2 L1&L3 : G2.H1.G7.H4 L2&L3 : G4.H2.G7.H4 Non-touching loops taken three at a time: L1,L2&L3: G2.H1.G4.H2.G7.H4

  32. sum of all individual loop gains According to Mason’s 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 ibyeliminating 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 Mason’s Rule as :

  33. 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.

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