LAN/WAN Optimization LAN/WAN Optimization Techniques Techniques Chp.1~Chp.4 Chp.1~Chp.4 Harrell J. Van Norman Harrell J. Van Norman Presented by Shaun Chang Presented by Shaun Chang
Jan 31, 2016
LAN/WAN Optimization LAN/WAN Optimization TechniquesTechniques
Chp.1~Chp.4Chp.1~Chp.4
Harrell J. Van NormanHarrell J. Van Norman
Presented by Shaun ChangPresented by Shaun Chang
OutlineOutline
• NetworksNetworks– Local-Area Networks (LANs)Local-Area Networks (LANs)– Wide-Area Networks (WANs)Wide-Area Networks (WANs)
• Network DesignNetwork Design
• Network Engineering ProcessNetwork Engineering Process
• Network Design ToolsNetwork Design Tools
NetworksNetworks• LANsLANs
– Short-distance networks (less than 1 mile)Short-distance networks (less than 1 mile)– Data transfer between computers & devicesData transfer between computers & devices
• MANsMANs– Medium-distance networks (1 to 50 miles)Medium-distance networks (1 to 50 miles)– Voice, video, data transferVoice, video, data transfer
• WANsWANs– Long-distance networksLong-distance networks– Voice, data, video transfer between local, metrVoice, data, video transfer between local, metr
opolitan, campus, premise networksopolitan, campus, premise networks
LANsLANs
• StandardsStandards– EthernetEthernet– Token BusToken Bus– Token RingToken Ring– FDDIFDDI
Internetworking Internetworking
• Communications HardwareCommunications Hardware– BridgesBridges– BroutersBrouters– RoutersRouters– GatewaysGateways
WAN AccessWAN Access
• Communications HardwareCommunications Hardware– ModemsModems– Multiplexers (FDM, TDM, STDM)Multiplexers (FDM, TDM, STDM)– Channel BanksChannel Banks– CSUs, DSUsCSUs, DSUs
WAN TransportWAN Transport• PrivatePrivate
– Twisted PairTwisted Pair– T1T1– Fractional T-1Fractional T-1– T3T3– Fractional T-3Fractional T-3– DDSDDS– NHDNHD– SONETSONET– SatelliteSatellite– MicrowaveMicrowave
WAN TransportWAN Transport
• PublicPublic– Circuit SwitchingCircuit Switching
•dial-up linesdial-up lines
• ISDNISDN
– Packet Switching Packet Switching •X.25X.25
•Frame RelayFrame Relay
•ATMATM
•SMDSSMDS
OutlineOutline
• NetworksNetworks
• Network DesignNetwork Design– LAN DesignLAN Design– WAN DesignWAN Design
• Network Engineering ProcessNetwork Engineering Process
• Network Design ToolsNetwork Design Tools
Network DesignNetwork Design
• Cost-performance trade-offsCost-performance trade-offs– Prices of the hardwarePrices of the hardware– ReliabilityReliability– Response timeResponse time– AvailabilityAvailability– serviceabilityserviceability
LAN DesignLAN Design• Media choicesMedia choices
– Twisted-pairTwisted-pair– Coaxial cableCoaxial cable– Fiber opticsFiber optics– Wireless systemsWireless systems
• Media access protocolMedia access protocol– Token ring, token bus, Ethernet CSMA/CDToken ring, token bus, Ethernet CSMA/CD
• Cabling strategiesCabling strategies– Intelligent hub wiringIntelligent hub wiring– Distributed cabling systemDistributed cabling system– Centralized proprietary cablingCentralized proprietary cabling
LAN simulation toolsLAN simulation tools
• LAN simulation tools provide measures ofLAN simulation tools provide measures of– UtilizationUtilization– ConflictsConflicts– DelaysDelays– Response timesResponse times
• Identify cost-performance-reliability trade-Identify cost-performance-reliability trade-offsoffs
• Find the bottlenecks in network Find the bottlenecks in network performanceperformance
WAN DesignWAN Design
• Designs based on various routing, Designs based on various routing, multiplexing, and bridging multiplexing, and bridging approachesapproaches
• More complexMore complex– Tariff data changes frequentlyTariff data changes frequently– Many new service offeringsMany new service offerings– Numerous networking optionsNumerous networking options
OutlineOutline
• NetworksNetworks
• Network DesignNetwork Design
• Network Engineering ProcessNetwork Engineering Process– Network AwarenessNetwork Awareness– Network DesignNetwork Design– Network ManagementNetwork Management
• Network Design ToolsNetwork Design Tools
Network Engineering Network Engineering ProcessProcess
Network awareness
Network design
Network manageme
nt
Network awarenessNetwork awareness
• Technology assessmentTechnology assessment
• Current trafficCurrent traffic
• Equipment inventoryEquipment inventory
• Forecasted growthForecasted growth
• Operational evaluation criteriaOperational evaluation criteria
Network designNetwork design
• Network design toolNetwork design tool
• Cost/performance breakeven Cost/performance breakeven analysisanalysis
• Equipment acquisitionEquipment acquisition
Network managementNetwork management
• ConfigurationConfiguration
• Fault managementFault management
• Performance managementPerformance management
• Maintenance and administrationMaintenance and administration
Total network engineering decision Total network engineering decision approachapproach
OutlineOutline
• NetworksNetworks
• Network DesignNetwork Design
• Network Engineering ProcessNetwork Engineering Process
• Network Design ToolsNetwork Design Tools– SimulationSimulation– Analytic ModelsAnalytic Models– BenefitsBenefits– LimitationsLimitations
Experimental measurements Experimental measurements PrototypingPrototyping
• Quality measurement & monitoring Quality measurement & monitoring toolstools
• CumbersomeCumbersome
• ExpensiveExpensive
• Time-consumingTime-consuming
• Relatively inflexibleRelatively inflexible
SimulationSimulation
• Is driven by a stream of Is driven by a stream of pseudorandom numberspseudorandom numbers
• Time-consuming, but more accurateTime-consuming, but more accurate
• Overcome problems caused by Overcome problems caused by simplifying assumptionssimplifying assumptions
Analytic ModelsAnalytic Models
• Require a high degree of abstractionRequire a high degree of abstraction• Difficult to evaluate the performance of Difficult to evaluate the performance of
a complex communication systema complex communication system• Queuing theory plays a major roleQueuing theory plays a major role• Calculate answers in near real-timeCalculate answers in near real-time
BenefitsBenefits
• Minimize CostsMinimize Costs
• Reduce Design TimeReduce Design Time– 1000-devices network designed in about one 1000-devices network designed in about one
hourhour
• Ensure Proper PerformanceEnsure Proper Performance– Avoid costly overbuilding and rebuildingAvoid costly overbuilding and rebuilding
• Assist Design EvaluationAssist Design Evaluation– Evaluate vendor claims and networking Evaluate vendor claims and networking
strategiesstrategies– Verify performance predictionsVerify performance predictions
Benefits--Minimize CostsBenefits--Minimize Costs
• Low-speed access WAN lines are Low-speed access WAN lines are consolidatedconsolidated
• The best transmission services are The best transmission services are obtainedobtained
• Unnecessary facilities are eliminatedUnnecessary facilities are eliminated
• Communications equipment Communications equipment configurations are optimizedconfigurations are optimized
• Save 20 to 45 percentSave 20 to 45 percent
Overbuilding and RebuildingOverbuilding and Rebuilding
LimitationsLimitations
• Cost $5000-100,000 for WAN Cost $5000-100,000 for WAN optimization design tools and up to optimization design tools and up to $10,000 for LAN$10,000 for LAN
• Capable and knowledgeable network Capable and knowledgeable network designers are requireddesigners are required
• Input parameters of traffic volumes, Input parameters of traffic volumes, message sizes, etc are not good enoughmessage sizes, etc are not good enough
• Network design is a process of iterative Network design is a process of iterative design and refinementdesign and refinement
Feedback control Feedback control mechanismsmechanisms
Overall Gain of a SFGOverall Gain of a SFGThe 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.
Mason's RuleMason's RuleMason'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 :
R
CT
Input
Output
iiPT
Where,
Pi : the total gains of the ith forward path
= 1 - ( of all individual loop gains) + ( of loop gains of all possible non-t
ouching loops taken two at a time) - ( of loop gains of all possible non-touchi
ng loops taken three at a time) + …
i = the value of evaluated with all gain loops touching Pi are eliminated.
Notice: In case, all loops are touching with forward paths (Pi ) , i = 1
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.
V5(s)
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
According to Mason’s rule:
= 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). 1 = 1 - G7.H4 …..……. ……… (3)
Now Substituting equations (1) , (2) & (3) into the Mason’s Rule as :
]1][[ 475432111 HGGGGGGPPT ii
sum of all individual loop gains
sum of gain products of all possible non-touching loops
taken two at a time
sum of gain products of all possible non-touching loops
taken three at a time
iiPT
Using of Mason's Rule to solve Using of Mason's Rule to solve SFGSFG
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
5) Determine i
6) Substitute all of the above information in the Mason's formula.