QoS _Syn 7
Transcript of QoS _Syn 7
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EconomicsofQuality of Service
Jitender Singh
Jetendar YadavAnkit Anand
A S y n d ica te 7 Pre se n ta tio n
B h a n u G a rg
G eken EtteR o m ita R a zd a n
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Economics of QoS
In simple words it is an analysis ofcost and benefit associated withdelivering a particular quality of
service.
B e n e fitIn cre
ased M arket share
In crea sed R ev en u e
In cre a se d Pro d u ctiv ity
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Pre v e n tio n co stFa ilu re C ost
A p p raisal cost
.1 N e t w o rk
re la te d
.2 O rg a n iza tio n
re la te d
.3 Process
re la te d
.4 P u b licity5.
.1 N e tw o rk re la te d
.2 &Pro b le m
co m p la in t
h a n d lin g
.3 Poor p rod uct
la u n ch
.4 R e v e n u e re b a te s
& litigation
.5 Loss of m arket
share
.6 O rg a n iza tio n
re la te d
.1 Te ch n ica l
m e a s u re m e n t
.2 O p in ion m ea surem en t
C ost
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1. Failure cost: cost associated withthe failure to achieve a
satisfactory level of QoS 2. Appraisal cost: cost relates to
activities concerned with the
assessment of QoS 3. Prevention Cost: cost necessary
to ensure that a desired level ofQoS is obtained
o st o f Q u a lityThe Cost of quality isnt the price of creating a quality
product or service, it is cost of not creating a quality
product and services
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Traditionally Total cost of service is summation offailure and prevention cost. However it ignoresthe benefits aspects of QoS and may not be themost profitable solution
%0 defective%100defective
Qualitycost
Optimum qualitylevel
Prevention cost Failure
cost
Total qualitycost
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Network prevention cost:
3 parameters that affects the design &dimensioning of the network are:
Cost
Performance
Throughput
Generally, the designed n/w is optimized forminimum cost for a prescribed throughput andperformance..
QoSis broadly the summation of individualperformance of each link and node making upthe connection..
Tradeoff between prevention cost & Failurecost..capital expenditure & operating
expenditure
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Prevention Costs
Prevention costs are those which arenecessary to ensure that theproducts and services delivered tocustomer, that is the offered
quality, meet an acceptable level ofquality. They include:
Network prevention Costs Network Resilience Costs
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Network Prevention cost
Primarily associated with networkand design
Main Parameters
Cost Performance
Throughput
To obtain good performance there istrade off between nodes and linksin such a way that it minimizesoverall cost
Trade off between Local access
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Network Prevention Costs(Maintenance)
C
P
E
L
E
L
ET ET E
C
P
E
N T P N T
P
Loca
lLoop
Loca
lLoop
Ju n ctio n Ju n ctio nTru n k C ircu it
OSperceived
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MTTR
Fault detection, fault localization, faultnotification, hold-off & computationtime
It is a critical QoS parameter & isaggregate time of process from faultreception to solution
Queuing, travelling & repair
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Network Prevention Costs
(MTTR)
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MTBF
Mean time between failures
Use of equipment with less stringentMTBF may reduce capital costrequirement but to meet customersrequired availability moremaintenance costs may be required
A trade off between capital &operating cost and a optimumshould be to minimize whole life
cost
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Network Prevention Costs
(Effect of ageing)
F
A
U
L
T
L
I
A
B
I
L
I
T
Y
Time
S e ttlin g
p e rio dE ffe ct
O f
a g e
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Effect of intervention
Capacity is provided in increments tomeet growth for a period of time inlocal loop
Often there is need of manualintervention at flexibility points
Services for new customer can hinder
due to non availability
Sufficient capacity independent offorecast
Will increase the capital cost but physical
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Network Prevention Costs
(Effect of intervention)
In te rv e n tio
nTim
effect of intervention on fault liability
FA
ULT
LIA
BILITY
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Network Resilence
Physical Layer (1): Protection againsttransmission failures
Function Layer (2,3): concerned with
traffic routing & congestion innodes & links
Capex involved is high, so
combination is necessary to meetthe needs of network operators atan acceptable cost
Difficult to analyze the cost and
benefits
R l ti hi b t
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Relationship betweenrestoration and effective cost
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Failure Cost
Failure costs are incurred when a product failsto conform to its design specifications.
Internal Failure Cost-
Costs associated with defects found before
the customer receives the product or serviceExternal Failure Cost-
Costs associated with defects found after thecustomer receives the product or service
Such costs can decimate profits
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Cost
Net cost of scrapNet cost of spoilageRework labor andoverheadRe-inspection ofreworked products
Retesting of reworkedproductsDowntime caused byquality problemsDisposal of defectiveproductsAnalysis of the causeof defects inproduction
Re-entering databecause of ke in
Cost
Cost of field servicingand handlingcomplaintsWarranty repairs andreplacementsRepairs and
replacements beyondthe warranty periodProduct recallsLiability arising fromdefective productsReturns andallowances arisingfrom quality problemsLost sales arising from
a reputation for poorualit .
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Eff t C t d P fit D T
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Effect on Cost and Profit Due ToFailure
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Failure Model
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Investigation of Failure Cost
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Cost of failure of network
integrity1.Catastrophic failure: Where large outages occurs like
failure of switching nodes.
It can be very costly in terms of lostrevenue.
This cost can be evaluated if theaverage customers is knowntogether with the average trafficand the duration of outage.
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Cont.
2. Failure of inter connect
Where all the calls passing betweenthe networks are prevented from
completing.
Here lost revenue can be calculatedand would affect both the operator
and the one in whose network thecall terminates.
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Cont
3. Failure of particular service
Failure of one service or services inone or other network or those that
require interoperatibility,theoretical revenue loss can becalculated.
4. Degradation of performance. Its the performance that DOESNT
affect the call completion. For eg-
high error rate.
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Protection at Points ofinterconnect
Detail and unambiguous interconnectand feature standards insuringcompatibility of implementation ofstandards require close cooperation
between operators. Mediation and policing devices, and
cost apportionment betweenoperators will be a major issue.
Conformance testing- it may requireexpensive captive models as well asinternetwork trials and it raises issuesregarding when such testing takes
place.
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Major issues when new services areinterconnected or when major
software upgrading takes place
Responsibility for conformanceapproval
Self certification
Funding of test models
Requirement for testing
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Commercial implications of an operatorrestricting access to its network
Potential loss of revenue to the serviceprovider or network operator deniedaccess.
The costs to customers who might bedenied cheaper services- impossibleto quantify.
Reduction in market growth. Low Innovation and development of
new services resulting from thereduction of competition and lack ofcreative service providers.
Conflict with regulator whose policy is
to open networks for interconnection
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Network modernization
Good QoS and new services are difficult toachieve when a network operator ismodernizing its network because of the legacyburden of obsolete plant.
it is necessary for the network operator toschedule carefully the order in whichexchanges are modernized.
Early priorities must obviously be given to
large towns with high business penetration. It becomes more difficult to prioritize the
residual majority of exchanges to ensure thatthe supply of digital exchanges is deployed in
the most cost effective manner, particularlywhen re lacin exchan es.
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The financial worth of modernization can beassessed by trading off the capitalrequired to modernize each exchangeagainst the savings in operating costs and
the incremental revenue from newservices, usage stimulation from improvedQoS and the loss of revenue protectedfrom competitors.
There is evidence that improved QoS can
stimulate usage. Conversely in a partially modernized
network, the variability of performancedue to the mix of analogue and digitalroutings can give rise to increased
complaints about QoS.
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Clearly reduction in congestion due toautomatic alternative routing anddynamic alternative routing strategiestogether with network traffic
management increases the trafficthroughput and hence revenue.
Some calls lost due to congestion areeventually successfully repeated.
The repeat call button on moderntelephones assists in this, although itcan exacerbate the problems of heavycongestion by exponentially
increasing call attempts.
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Appraisal Cost
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Definition
Appraisal costs are costs that occurbecause of the need to control productsand services to ensure a high quality levelin all stages, conformance to quality
standards and performance requirements.Examples include the costs for:
Checking and testing purchased goods
and services In-process and final inspection/test
Field testing
Product, process or service audits
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Examples of Appraisal Cost
Incoming Inspection
Testing Inspection in process
Quality audits
Incoming test and laboratory tests
Checking labor Laboratory or other measurement service
Setup for test and inspection
Test and inspection material
Outside endorsements for certification Maintenance and calibration work
Product reengineering review and shippingrelease
Field testing
Example :
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Example :Software
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Network management
Network management is the use ofcomputer support system to reducefailure costs and to improve the
performance of the network. Such systems are effective when
they interact with the network witheach other in a coherent fashion.
A well structured set of networkmanagement support systemsshould detect problems before they
affect customers.
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Service Management
No matter how good the networkmanagement is the impact on QoScan be reduced by a poor interface
to the customer. Whilst network management ensures
that the operation of the network is
optimised to the desiredperformance levels, servicemanagement should optimiseservices to the best of customers
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Service Management
Service management can be definedas the coordinated management ofa portfolio of service customers use
and gives the network providers asingle integrated view of itscustomers.
It includes customer reception. The development of network and
service mgt support systems is
very expensive.
C t ti f ti
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Customer satisfactionMODEL
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Case Study
Economies of QoS AllocationStrategies in Internet
Junseok Hwang, Syracuse University
Martin Weiss, Pittsburg University
Addresses the technical andeconomic problems of QoS-
Interconnection
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Issues
Network valuation vs. incentive ofoptimal interconnection
The economic affect of various QoS-mechanisms and QoSinternetworking options among the
interconnecting networks.
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Method
Modeled the opportunity costfunctions for bandwidth of QoS byusing the proxy usable bandwidth
The values were assessed bysimulating the parameters of thecost functions for various QoSnetworks
Using the cost functions of variousQoS networks, the optimal strategyfor the QoS allocation was
discussed
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Analysis
QoS-Interconnection is aboutconnectivity for multiservicenetwork services
Different QoS service may havedifferent cost functions, andadditional services can be both
beneficial and costly to thenetworks
QoS Outsourcing
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BW Cost Vs Quality
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Results
Cooperative Interconnection : BestStrategy as it lowers end-to-endQoS cost
QoS outsourcing : Saves own cost upto 70% : Increase counterparts
cost uptoa factor of 6 : Worst Case total cost
2x of joint
optimal cost
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Conclusion
In the absence of QoS-basedinterconnection prices, that powerfulincentives exist for networks to
reduce their local costs byoutsourcing quality to the othernetwork. This behavior produces
costs that are above the globallyoptimum costs and transfersignificant costs onto the othernetwork.
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Summarizing QoS
Quality of service is the ability toprovide different priority todifferent applications, users, or
data flows, or to guarantee acertain level of performance to adata flow
(Source Wikipedia)
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Is it about QoS...only
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QoS.not sufficient alone
Technological consideration
Economic consideration
Subjectivity
End User Perception
Customer Experience
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What is QoE ?
Quality of Experience (QoE) is asubjective measure of a customer'sexperiences with a vendor
(Source - Wikipedia)
QoE = f {Change in Experience w.r.t.vendor}
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Service Experience Matrix
Q o E
High Low
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In Brief
QoS Vendor Side Importance
QoE Customer Side Importance
Economics = f {Return onInvestment, Value forMoney}
= f {QoS * QoE}
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Thank You
Your queries are welcome