1. R E S E A R C H P O S T E R P R E S EN T A TIO N D E S IG N © 2 01 5
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The United StatesGovernment DSLnetwork operatesacross 5statesandWashington D.C. The current sizeof the
network results inunnecessary expense. Thegovernment would liketo minimizethe cost of theservices across this
region. To do this, costswill be analyzed acrosstheregion and underutilized Private Virtual Channel (PVCs) and
circuits will be eliminated. Wherepossible, customerswill be consolidated onlower-cost PVCs; unnecessary circuits
will be eliminated.The developedalgorithmwill resultin theminimal amount of circuitsnecessary for operation.
The resultant algorithmis aserviceassignment problem that isconstrained by region, level of service, and capacity
and can be generalizedto minimizecosts of other government serviceswith theseconstraints.
ABSTRACT
OBJECTIVES
1. Eliminate all PVCswith 0%Utilization and 0Sessions.
2. Organize each circuit by VCIrange.
3. Select an individual circuit to consolidate to based on:
(1) lowest cost and (2) minimal effort. Thisisdone foreach range.
4. Ensure each total circuit capacity isless than 70%.
5. If a circuit violatesthecapacity constraint, then assign a
portion of the PVCs in a given rangeto a new circuit.
6. If all PVCs wereremovedfrom arouter, then removeits
respective router and switch as well.
MATERIALS
AND
METHODS RESULTS CONCLUSION
Optimization of the networkoccurred byregion. After optimizing each region, asummary wasmade of all
modifications. Asyoucan see inTable 1,the sum of the total PVCsdecreased bymore than 600. Decreasing thetotal
amount of PVCs allowed for more optimal consolidation. If a circuit wasnotcrucial, it wasshut down. Thereduction
of circuits per region isshown below inFigure 7. The strict constraintsresulted in a70% decrease in the number of
circuits. After consolidation, the next stepwasto find theassociated cost per circuit. After optimization, thetotal cost
of the network wasapproximately $3M(original cost wasapproximately $11M).
FUTURE
PLANS
This modified assignment algorithm can be appliedto any service allocation problem with thesameconstraints
(namely, region, servicelevel and capacity). Thealgorithm can accept data fromany type of network. It will
eliminate unused or underutilized equipment therebyreducing costs of the system.The methodis easily manipulated
to accept endlesstypesof constraints and assumptions. By adding asimulationto theproblem, we hope toexpand
model functionality byallowing input distributions of varioustypes. Bysimulatingdifferenttypesof input, it will be
possible to study networkgrowthover aperiod of time. Theresults gathered will allowthediscretedistribution of
the network to be determined as well asthe expectedvalue and thevarianceof servicesneededin order for a
particular region to remain operable. In addition tothefluctuation of servicesutilized inthe network (here, PVCs),
simulation will be ableto identify howcostsin thenetwork fluctuate. Thisinformation will be used, along with
sensitivity analysis, to identify variablesmost susceptible to change.The analysiswould then createan optimaland
predictive model that can beused for consolidation. Thefinal outcome of the project isto build areal-timepredictive
dashboard. This will provide theability to easily identify coststhat aremovingtoward anout-of-control condition.
Each region in the networkcontainsrouterswhich distributenetwork connectionsto customers throughan assigned
circuit. Each circuit contains Private VirtualChannels (PVCs), eachof which can hold multiple customers. Figure1
illustrates a simple network asdescribed above. Customersarelinked to acircuit througheither a port or a transport
connection. Feeslinked toportsandtransport connectionsare thebasisfor costing the network.Totalcost per circuit
for each region is summarized in thematrix foundin Figure2. Since costs are dependenton circuit and not service
package, C1i =C2i =. . . = Cni .
To begin consolidation,every PVCwithzero sessionsand zero utilizationwas eliminated. Each PVChasarespective
VCI code whichspecifies the service package. Originally,each circuit contained amixture of VCI ranges. Figure3
summarizes thisrelationship. This informationwasusedto identify eachcircuit’s ability tooperate under each
service package.
During customer migration, PVCs must be assigned to acircuit capable of carrying the required VCI range. If a
circuit did not includePVCsof a service package, signified by Xij = 0,thenit isassumed it will beunable toprovide
required services. Thecorresponding cost coefficient,Cij,is set arbitrarily large toensure that thecircuit will be not
be selected.This modification isanapplication of theBigMmethod and issummarized intheadjustedcost matrix
shown in Figure 4. The circuit(s) selected to hold aspecificrangeis then determined by thelowestannual cost.To
ensure this circuit does not exceed capacity as the network grows, total capacity of the circuit isset under 70%.If
capacity violates thisconstraint, additional circuitsare added byusing theminimal cost objective.The assignment
Yij and total circuitsrequired are shown in Figure 5.The final cost iscalculated by multiplying the adjusted cost
matrix and assignment matrixasshownin Figure6.
ACKNOWLEDGEMENTS/REFERENCES
References:
Acquired necessary knowledgeandinformation about thedatafrom Colonel DouglasMatty, Lieutenant Colonel
Keith Chinn, Senior Manager TomNesslage, and Senior Manager GeorgeRiggins.
Advised and mentored by Dr. ChristyCrute, withher knowledgeandstrong background inthe OperationsResearch
field.
Colonel
Douglas
Matty,
Lieutenant
Colonel
Keith
Chinn,
Senior
Manager
Tom
Nesslage
Alex
Barclay,
John
Yannotty,
Christy
Crute,
Ph.D
Cost
Minimization
of
a
Government
DSL
Network
-­‐SMSR3
-­‐SMSRx
1 /3 2
1 /3 3
1 /3 4
1 /3 5
1 /3 6
1 /xxx
Route r
(-­‐RTRx or
-­‐ATMx)
Circuit
ID
xx.xxxx.xxxxxx.xx
Circuit
ID
xx.xxxx.xxxxxx.xx
Circuit
ID
1 2 .ABCD.3 456 78 .EF
Inte rface
0 /0/0
Inte rface
0 /0/1
Inte rface
X/X/X
1 /4 3
1 /4 7
1 /4 3
1 /4 5
1 /3 5
1 /4 3
1 /6 1
1 /4 4
Service
Pack
Circuit Range Capacity
70% of
Capacity
A 1/32 - 1/199 168 118
B 1/200 - 1/299 100 70
C 1/300 - 1/399 100 70
CRITERIA
FOR
ELIMINATION
CONSTRAINTS
The model reducedannual expenses fromroughly$11Million to $3 Million. Features of the model include:
• Virtually unlimited dataallowed
• Easily modifiable constraints and assumptions
• Not limited to DSLnetworks(canbe applied to expenditures wherethe constraint istominimize expensewhile
distributing specificservices tocustomers)
• Additionally, the constructed algorithm isdesigned ina flexible manner to allow for any magnitude of dataset.
Also, the algorithm isnot limitedto aDSLnetwork,asit can beapplied toproblemsin different fieldswhich involve
minimizing expensescaused by a surplusof equipment whiledistributing specific servicesto customers.
The table above summarizes the resultsthat were foundthroughconsolidation. The original DSLnetwork
started with a total of twothousandPVCs. After the algorithmcreated wasappliedto thedata, thetotal number
of PVCs diminished. Thelargest regionthat underwent consolidation wastheregion, Eastern Massachusetts.
The model outputs the associatedfee per circuit by summing therespectiveport and transport fees. After these
fees are summed, thetotal is then amplified by the amountof months whichmust bepaidto total a year.Not
every circuit hasan associatedfee per month. Thisallowsusto obtain an average monthly cost, making the
data easily comparable.Withonequick glanceat thetable abovemany believethat most expensiveregions
would be thosewho'stotal feesare the highest. In one sensetheywouldbecorrect, but respectively they are
not. Majority of the regionswithsixdigit feetotalsalsohaveanabundant about of PVCswiththe region.To
get a better look atthe respectivecost per PVCwithin aspecificregion, theTotal PVCwasdividedby there
particular Total Fees. As seem within theAverage Cost Per PVC,keepingthese smaller regionsare actually
sustainably more expensivethanthat larger regions.
0
2
4
6
8
10
12
14
16
Western,
Ma
Eastern,
Ma
NY
Metro
Poughkeepsie,NY
Albany,
NY
Syracuse,
NY
Bimgington,
NY
Buffalo,
NY
Altlantic
Coastal,
NJ
Delaware
Valley,
NJ
North
Jersey,
NJ
Captial,
PA
Philidelphia,
PA
Northeast,
PA
Pittsburgh,
PA
Washington,
DC
Baltamore,
MD
Hagerstown,MD
Culpeper,
VA
Richmond,
VA
Lynchburg,
VA
Norfolk,
VA
Figure
7:
Circuit
Consolidation
Cir cuit s
Bef or e
Consolidat ion Cir cuit s
Af t er
Consolidat ion
16
118
4
3
5
8
7
2
22
18
118
9
118
37
69
118
48
22
6
11
5
22
71
52
19
50
WESTERN
MA
EASTERN
MA
NEW
YORK
METRO
NY
POUGHKEEPSI E
NY
ALBANY
NY
SYRACUSE
NY
BI NGHAMTON
NY
BUFFALO
NY
ATLANTI C
COASTAL
NJ
DELAWARE
VALLEY
NJ
NORTH
J ERSEY
NJ
CAPI TAL
PA
PHI LADELPHI A
PA
NORTHEAST
PA
PI TTSBURGH
PA
WASHI NGTON
DC
BALTI MORE
MD
HAGERSTOWN
MD
CULPEPER
VA
RI CHMOND
VA
LYNCHBURG
VA
NORFOLK
VA
PVC
ASSIGNMENT
VCI
RANGE
A
VCI
Range
A
Fir st
Cir cuit VCI
Range
A
Second
Cir cuit
The figure below illustratesthe70% constraint capacity inVCI RangeA.Green bars signify PVCs assigned to
the first circuit, while red bars represent thosePVCswhich were consolidated toa second circuit.
• Consolidation must be completed separately by region.
• At least one circuit per VCI rangemust beleft operatingwithintheregion.For instance, if two service
packages arerequired for agivenregion, thenat least twocircuits must remainin thenetwork.
• PVC’s must beassignedby theservicepackage identification code.
• Each circuit is limitedto 70%capacitywhich allowsfor growth of thenetwork.Thus,a circuit designated to
VCI Range Acan havea maximumof 118PVC’s.Likewise, VCI RangesB and Ccan havea maximumof 70
PVC’s per circuit.
• A circuit is eligibleto runa service packageonly if it previously had PVCsof the specific packagepreviously
operating on it. This ensuresthe circuit selected has the capabilitiesto provideadequateservicesto the
customer. Note,if Circuit 1 didnot previously includea PVCof VCI RangeC,thenCircuit 1 isnot eligibleto
be assignedVCI RangeC during consolidation.
ASSUMPTIONS
• All PVCs with 0%Utilization and 0sessionscan beeliminated.
• Each PVC is a candidatefor migration.
• Migration costsareuniform across all PVCs.
• Specific VCI ranges constitutea unique service package.
• Each range hasa maximumcapacity of 168, 100, and 100PVC’s respectively.Eachcircuit capacity is
restricted to an ideal capacity of 70%. Thismeansacircuitcontaininga specific range cancontain a
maximum of 118, 70, and 70 PVC’srespectively. If thesebounds are exceeded, then anewcircuit is
added to the network and assigned theremaining PVCsinthe service package.
• Circuits that are assigned to aVCI range after consolidationmust have previously held PVC’swithin
the service package. For example,if circuit1 isassigned VCI rangeAasa result of consolidation,then
circuit 1 operated usingPVC’s of VCI rangeAbeforenetwork consolidation.
ALGORITHM
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Table 2
Table
1
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3
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6
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1
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