NTT Network Service Systems Laboratories

NTT Network Service Systems Laboratories

Network on Demand Service with Price-based Resource Control

IEEE/IFIP BoD 2010@OsakaIEEE/IFIP BoD 2010@OsakaIEEE/IFIP BoD 2010@Osaka

T Miyamura K Shiomoto

IEEE/IFIP BoD 2010@Osaka

T Miyamura K ShiomotoT. Miyamura K. ShiomotoNTT Network Service Systems Labs.

T. Miyamura K. ShiomotoNTT Network Service Systems Labs.

NTT Network Service Systems Labs.Today’s BoD service application scenario

• Today’s BoD service– A network provider offers high-capacity bandwidth to its

tcustomers– Basically, the connectivity is limited to Point-to-Point.– Customers often construct a part of their own network byCustomers often construct a part of their own network by

combining multiple point-to-point connections.

Today’s BoD serviceProvider’s network

P2P connection is initiated upon

222Physical network configurationPhysical network configuration

user request

NTT Network Service Systems Labs.Today’s BoD service application scenario cont’d

• Outline of our proposal– The price is basically determined by service parameters (e.g.,

h ldi ti b d idth t )a holding time, bandwidth, etc.)– Customers wish to minimize the total cost while maintaining

adequate service quality.q q y– We consider a new service that offers a minimum-cost

network configuration in combination with multiple point-to-point connectionspoint connections.

Today’s BoD service Our proposal (VNT service)

Point-to-point connection ₉Multi-point connection

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₉Point-to-point connection

₉Fixed bandwidth

₉Multi point connection

₉Flexible bandwidth & topology

NTT Network Service Systems Labs.Outline of Talk

1. Concept: VNT service2 R t l ith P i i2. Resource control with Pricing3. Numerical Examples3. Numerical Examples4. Concluding Remarks

44



55

NTT Network Service Systems Labs.

Virtual Network Topology (VNT)

• The network topology formed by optical paths and advertised to the higher layer is called VNT.

• VNT is re configured by optical paths setup/teardown• VNT is re-configured by optical paths setup/teardown.Virtual Network Topology

IP LayerVNT1 VNT2VNT1 VNT2

Optical Layer

6Physical Fiber Topology

NTT Network Service Systems Labs.Our proposal: VNT service

• A service provider network provides continuous connections among multiple customer sites.

– VNT provides a transport among customer’s sitesp p g– Provider accommodates multiple customers (i.e., VNTs)

• Bandwidth of each pipe connecting a pair of customer edges is automatically adjusted in accordance with traffic-demand changesj g

Customer 1 Customer n Traffic demand bet Site A and BCustomer 1 Customer n

A B

h of

w

ork

Residual Bandwidth

Traffic demand bet. Site A and B

VNT1 VNT n

band

wid

ther

’s n

etw

Allocated resources

Tota

l bpr

ovid

eCustomer’s t ffi d d

7Provider’s network

traffic demand

NTT Network Service Systems Labs.Our proposal: VNT service cont’d

• Merits– Customers: improves flexibility regarding bandwidth and p y g g

reduces OPEX and CAPEX– Providers: Improves efficiency of resource utilization

Conventional BoD Service VNT Service

Connectivity Point-to-Point Muti-pointy p

UNI (Data plane) Any (L1/L2/L3) Packet or Frame-based (L2/L3)Connection Triggered by customer Continuously establishedinitiation /release request Continuously established

Allocated bandwidth

Manually specified upon connection request

Automatically adjusted based on actual demand by service bandwidth connection request yprovider

Operation cost for Estimating traffic demand d/ h ldi i i No additional task is required

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Operation cost for customer network and/or holding time is very

complicated

No additional task is required for traffic demand variation

NTT Network Service Systems Labs.Challenges for VNT service

• Goal (Economics aspect)– We want to maximize the utility of users; at the same time, maximize

the profit of the service providers.p p• Possible problems

i) Each user share the same objective. Resource contention will occur.ii) Network cost increases if resources are provisioned to cover the peakii) Network cost increases if resources are provisioned to cover the peak

demand.• Our approach

W i t d i i h i i j ti ith TE t h l i– We introduce pricing mechanism in conjunction with TE technologies.

Customer 1 Customer ni) Avoid resource contention among users

ii) Reduce network cost by efficient use of resources

⇒ Topology Optimization (TE)

contention among users⇒ Pricing

Provider’s network


1. Concept: VNT service2 R C t l ith P i i2. Resource Control with Pricing3. Numerical Examples3. Numerical Examples4. Concluding Remarks

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NTT Network Service Systems Labs.Our final goal: price-based resource control

• Network resources in a provider's network for the VNT service are shared by multiple VNTs

• Some mechanism is required for avoiding the exhaustion or contention ofSome mechanism is required for avoiding the exhaustion or contention of network resources. – VNT optimization function computes optimal topology for a given demand – Pricing mechanism determines an adequate price and resource allocationPricing mechanism determines an adequate price and resource allocation

considering residual network resources and customer's benefit.

Input VNT Resource

Customer’s traffic demand

VNT optimization Resource allocation

Input Output

esou cemanager (VRM)

Network resource

Customer’s budgetp Resource allocation

PricePricingmechanism

usage

11Provider’s network•Measured from network•Requested by customer

•Feedback

NTT Network Service Systems Labs.Problem we are solving

• Build mathematical model for proposed services and investigate feasibility of price-based resource controlinvestigate feasibility of price based resource control1. Clarify the impact of price on resource allocation and users2 Evaluate effectiveness of optimized topology2. Evaluate effectiveness of optimized topology3. Investigate impact of user behavior (traffic demand

distribution)distribution)

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NTT Network Service Systems Labs.Model 1: Overview

• Service provider(SP)’s behavior– Allocate wavelength resources to users

Choose adequate price for a unit of wavelength– Choose adequate price for a unit of wavelength• User’s behavior

– Submit information about peak traffic demand and budgetP t i ti t th t f ll t d– Pay cost in proportion to the amount of allocated resources

• Resource allocation policy– Maximize the benefit of users under given constraints (for simplicity)

Total capacity (C)Total allocated Total capacity (C)

Resource for customer r (xr)

Total allocated resources (∑x )

SP NetworkUser’s Edge

Customer r

Customer 1

Customer 2

OXC WDM link

NTT Network Service Systems Labs.Model 2: Formulation

• Objective– Maximize the sum of user’s

benefit ( utility minus cost)benefit ( utility minus cost)Fig. Utility function

• Determine– Allocated wavelength resources

to each usersw*log(X/Xmin)

to each users– Note that unit price is a given

parameter in our model

• Subject to– Capacity constraint

B d t t i t X– Budget constraint– Service quality constraint

Xmin

* Logarithmic utility function is approximated

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* Logarithmic utility function is approximated by piece-wise linear function.



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NTT Network Service Systems Labs.Aims of numerical study

Aims:U d t d b i h t i ti f th d– Understand basic characteristics of the proposed architecture and investigate feasibility

Numerical experiments:1. Investigate impact of price1. Investigate impact of price2. Even traffic vs uneven traffic3 Eff ti f ti i d t l3. Effectiveness of optimized topology

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NTT Network Service Systems Labs.Conditions: Network and Traffic model

Network model– Simple 3 nodes topology with 32 wavelength per linkp p gy g p

• 3 customers are accommodated in SP network

– Each wavelength is dedicatedly allocated

T ffi d d d lTraffic demand model– Consider stable traffic matrix of even and uneven distribution

• 5 uneven traffic patterns were randomly generated• 5 uneven traffic patterns were randomly generated• Result for uneven traffic is average of 5 patterns

3 Customers Network model Traffic demand model3 Customers Network model Traffic demand model

Even distribution Uneven distribution

32 λ 32 λ

171732 λ

NTT Network Service Systems Labs.Conditions2: Topology optimization

• Simple single-layer optimization is considered. – Optimal route for wavelength path is calculated by our formulation.p g p y

• Optimized topology can utilize entire resources more efficiently.– Fixed topology: Always use a single hop path– Optimized topology: use a detour router in conjunction with sigle hop route

Fixed topology Optimized topology

A

B

A

B

Detour Path

Fiber

A

CPathA

CDirect Path

Detour Path

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NTT Network Service Systems Labs.Results 1: Impact of Pricing

• Evaluate social welfare and cost while varying price– Fixed topology & Even traffic pattern– Adequate pricing is beneficial for SP and usersq p g

• Avoids congestion and maximize revenue (=cost for users)

Fig. Impact of price on welfare and costg p p

Fig. Resource utilizationModeratelyModerately

usedWelfare used

Under

Welfare

CongestedCongestedUnder-utilized

Cost

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NTT Network Service Systems Labs.Results 2: Impact of uneven traffic

• Investigate the traffic patter on social welfare and resource utilization– Uneven traffic leads to inefficient resource utilization and lower welfare– Even traffic outperforms uneven traffic by 20+% for lower price. p y p– High prices suppresses customer’s demand and no significant difference

between even and uneven traffic pattern

Fig. Resource UtilizationFig. Social Welfare

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NTT Network Service Systems Labs.Results 3: Fixed vs optimized topology

• Investigate effectiveness of optimized topology under uneven traffic

Compensate uneven resource utilization and improve resource utilization– Compensate uneven resource utilization and improve resource utilization – More effective for lower price (about 10% gain for welfare)– No gain for optimized topology for even traffic distribution (not shown)

Fig. Resource UtilizationFig. Social Welfare

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NTT Network Service Systems Labs.Concluding Remarks

• Conclusion:– The VNT service can improve flexibility regarding bandwidth while reducing

operation overhead and maintaining advantages of existing BoD servicesoperation overhead and maintaining advantages of existing BoD services.– Considering today’s customer’s traffic usage (highly variable and uneven

distribution), topology optimization and resource control with pricing is beneficial.

– It is important to choose adequate price considering traffic demand and residual network resources.residual network resources.

• Further study:– Introduce more sophisticated optimization strategies (e.g., Multilayer TE)– Investigate the merit of service provider (how to utilize effectively residual

bandwidth)bandwidth)– Consider time-varying traffic demand– Establish the pricing strategies

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NTT Network Service Systems Labs.Backup Slides 2: Topology seen by user network

• Case 1: User site terminates optical paths routed on the providers network⁺ Some UNI signaling for controlling optical paths is required

• Case 2: User-Provider is packet-based interface. Provider offers IP routing p gfunctionality.⁺ User site regard Provider network as one large router.

BTopology Case 1:

B

Case 2:

A

BSeen by user

A

B

Provider’s network

C

B

C

BVNT

B

A

B

A

2424C

A

C

A

NTT Network Service Systems Labs.Backup Slides 1: Optimizing VNT

• Optical VNT is determined by traffic demand and physical network topology.

Case 1: Demand is high Case 2: Demand is low

BTraffic demand

g

10GbpsB

10Mbps

A

C

10Gbps

10Gbps

A

C1Gbps

600Mbps

VNTB

p

B

p

A A

2525

C C

NTT Network Service Systems Laboratories

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