Yu-Liang Liu1 On the Bandwidth Management for Hose-Model VPN Service GRADUATE INSTITUTE OF INFORMATION MANAGEMENT NATIONAL TAIWAN UNIVERSITY.

Yu-Liang Liu 1

On the Bandwidth On the Bandwidth Management for Hose-Management for Hose-

Model VPN ServiceModel VPN Service

GRADUATE INSTITUTE OF INFORMAGRADUATE INSTITUTE OF INFORMATION MANAGEMENTTION MANAGEMENT

NATIONAL TAIWAN UNIVERSITYNATIONAL TAIWAN UNIVERSITY

Yu-Liang Liu 2

OutlineOutline

•An Introduction to VPNAn Introduction to VPN•VPN Service Models (Bandwidth VPN Service Models (Bandwidth management)management)

–The pipe modelThe pipe model–The hose modelThe hose model

•Implementation Alternatives of the Implementation Alternatives of the Hose Model VPNHose Model VPN

•Hose-Model VPN Service ProvisioningHose-Model VPN Service Provisioning•Future WorksFuture Works

Yu-Liang Liu 3

Private NetworkPrivate Network

•A Private Network (PN) is establisheA Private Network (PN) is established by dedicated leased lines connectid by dedicated leased lines connecting several geographically dispersed sng several geographically dispersed sites (endpoints).ites (endpoints).

–Each site is a campus or a branch office Each site is a campus or a branch office of an enterprise. of an enterprise.

–Since the lines are dedicated, security aSince the lines are dedicated, security and Quality of Service (QoS) are ensured.nd Quality of Service (QoS) are ensured.

–But connecting a large number PN sites But connecting a large number PN sites with dedicated lines is expensive.with dedicated lines is expensive.

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Virtual Private NetworkVirtual Private Network

•Virtual Private Network (VPN) is a reVirtual Private Network (VPN) is a replacement for Private Network.placement for Private Network.

–A VPN establishes connectivity between A VPN establishes connectivity between a set of endpoints over a shared network a set of endpoints over a shared network infrastructure (eg: MPLS network backbinfrastructure (eg: MPLS network backbone).one).

–The goal of VPN is to provide endpoints The goal of VPN is to provide endpoints with a service comparable to Private Netwith a service comparable to Private Network.work.

–Thus providers of VPN services need to Thus providers of VPN services need to address QoS and security issues.address QoS and security issues.

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VPN Three TypesVPN Three Types

•In terms of commercial applications, In terms of commercial applications, VPN can be classified into three typeVPN can be classified into three types:s:

–Access VPN (a.k.a Remote Access VPN)Access VPN (a.k.a Remote Access VPN)–Intranet VPN (a.k.a Enterprise VPN)Intranet VPN (a.k.a Enterprise VPN)–Extranet VPN (a.k.a E-commerce VPN)Extranet VPN (a.k.a E-commerce VPN)

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VPN Three Types (con’t)VPN Three Types (con’t)

Enterprise A

Enterprise B

Enterprise A

Nomadic user

Shard Network

or

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OutlineOutline




•Hose-Model VPN Service Hose-Model VPN Service ProvisioningProvisioning

•Future WorksFuture Works

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VPN Service ModelsVPN Service Models

•VPN customers need a flexible VPN customers need a flexible ways to specify their bandwidth ways to specify their bandwidth requirement.requirement.

•Two common VPN service Models Two common VPN service Models areare

–The Customer-pipe modelThe Customer-pipe model–The Hose modelThe Hose model

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The Customer-Pipe The Customer-Pipe ModelModel

•In this model, VPN customers In this model, VPN customers buy a customer-pipe for each buy a customer-pipe for each endpoints pair.endpoints pair.

•VPN customers need to specify VPN customers need to specify bandwidth requirement of each bandwidth requirement of each customer-pipe in advance.customer-pipe in advance.

•VPN service provider uses VPN service provider uses a path a path between endpoints pairbetween endpoints pair to to implement a customer-pipe.implement a customer-pipe.

–VPN service provider also need to VPN service provider also need to allocate adequate bandwidth along allocate adequate bandwidth along the path.the path.

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The Customer-Pipe Model The Customer-Pipe Model (con’t)(con’t)

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The Pro and Cons of the The Pro and Cons of the Customer Pipe ModelCustomer Pipe Model

•ProPro– The task of bandwidth allocation The task of bandwidth allocation becomes more simple.becomes more simple.

•Con Con –It requires the customer to have It requires the customer to have precise knowledge of the bandwidth precise knowledge of the bandwidth requirement of each endpoints pair requirement of each endpoints pair in advance.in advance.

–Bandwidth made available to a Bandwidth made available to a customer pipe cannot be allocated customer pipe cannot be allocated to other traffic.to other traffic.

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Motivation for the Motivation for the Hose-ModelHose-Model

•VPN customers may unwilling to VPN customers may unwilling to unable to know the bandwidth unable to know the bandwidth requirement between each requirement between each endpoints pair in advance.endpoints pair in advance.

–This is especially true when the This is especially true when the number of endpoints per VPN is number of endpoints per VPN is large.large.

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The Hose ModelThe Hose Model•In this model, VPN customers In this model, VPN customers only need to specify two only need to specify two parameters for each endpoint:parameters for each endpoint:

•Egress bandwidth requirementEgress bandwidth requirement: : the bandwidth for aggregate the bandwidth for aggregate outgoing traffic from the outgoing traffic from the endpoint to all the other endpoint to all the other endpoints.endpoints.

•Ingress bandwidth requirement:Ingress bandwidth requirement: the bandwidth for aggregate the bandwidth for aggregate incoming traffic out of all the incoming traffic out of all the other endpoints to this endpoint.other endpoints to this endpoint.

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Advantages of the Hose Advantages of the Hose ModelModel

•Ease of specificationEase of specification•FlexibilityFlexibility

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Challenge of Provision Challenge of Provision the Hose Model VPNthe Hose Model VPN

•From a VPN service provider’s persFrom a VPN service provider’s perspective, it is more challenging to suppective, it is more challenging to support the hose model VPN:port the hose model VPN:

–The need to meet the bandwidth requireThe need to meet the bandwidth requirement with a very weak specification.ment with a very weak specification.

–This complicate the VPN’s bandwidth This complicate the VPN’s bandwidth management issue.management issue.

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OutlineOutline

•An Introduction to VPNAn Introduction to VPN•VPN Service ModelsVPN Service Models


•Implementation Alternatives of Implementation Alternatives of the Hose Modelthe Hose Model

•Hose-Model VPN Service Hose-Model VPN Service ProvisioningProvisioning

•Future WorksFuture Works

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Implementation Implementation Alternatives of the Hose Alternatives of the Hose

ModelModel

•The most important implementation The most important implementation alternatives for the hose model VPNs alternatives for the hose model VPNs are:are:

–Provider-pipe algorithmProvider-pipe algorithm–Hose-specific state algorithmHose-specific state algorithm–VPN-specific state algorithmVPN-specific state algorithm–Tree routing algorithmTree routing algorithm

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Provider-Pipe schemeProvider-Pipe scheme

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Hose-specific state Hose-specific state schemescheme

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VPN-specific state VPN-specific state schemescheme

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Tree RoutingTree RoutingSchemeScheme

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Is the Hose Model a Viable Is the Hose Model a Viable AlternativeAlternative

• The main question to introduce the hosThe main question to introduce the hose model in ISP networks is how does it re model in ISP networks is how does it relate to the customer pipe solution in teelate to the customer pipe solution in terms of bandwidth efficiency.rms of bandwidth efficiency.

• The flexibility of the hose model will neThe flexibility of the hose model will never pay off if it requires significant overver pay off if it requires significant overprovisioing compared to customer-pipe provisioing compared to customer-pipe models. models.

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Generate Comparable Hose Generate Comparable Hose Model ParametersModel Parameters

EndpoinEndpoint 1t 1



EndpoinEndpoint 1t 1 11 22



Ingress Ingress BandwidthBandwidth

Egress Egress BandwidthBandwidth

Endpoint 1Endpoint 1 44 33



Customer-Pipe Model parameters:

Hose-Model parameters:

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Overprovisioning FactorOverprovisioning Factor• The ratio between the bandwidth reserThe ratio between the bandwidth reser

vation of the hose and the customer-pipvation of the hose and the customer-pipe model is called e model is called overporvisioning factoverporvisioning factoror. It is a good indicator of the required . It is a good indicator of the required extra capacity.extra capacity.

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Experimental ResultsExperimental Results

Provider-pipe

Hose-specific state

Tree routing

VPN-specific state

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OutlineOutline




•Hose-Model VPN Service ProvisioningHose-Model VPN Service Provisioning•Future WorksFuture Works

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Hose-Model VPN Service Hose-Model VPN Service ProvisioningProvisioning

• In terms of VPN service provisioning, servicIn terms of VPN service provisioning, service provider must establish multiple VPNs on te provider must establish multiple VPNs on the network backbone in an on-line manner.he network backbone in an on-line manner.– The available bandwidth for VPN service on linkThe available bandwidth for VPN service on link

s of the network backbone is finite.s of the network backbone is finite.– VPN setup request arrive one by one independenVPN setup request arrive one by one independen

tly.tly.– Each VPN setup request corresponds to a Hose-MEach VPN setup request corresponds to a Hose-M

odel VPN to be established.odel VPN to be established.– Information about future VPN setup request is uInformation about future VPN setup request is u

nknown.nknown.

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Hose-Model VPN Service Hose-Model VPN Service ProvisioningProvisioning

• If there is not enough residual bandwidIf there is not enough residual bandwidth on the link when the bandwidth is beth on the link when the bandwidth is being allocated, ing allocated, vrvrii will be rejected. will be rejected.

• In this scenario, the performance metriIn this scenario, the performance metric for comparing different VPN provisioc for comparing different VPN provisioning algorithm is ning algorithm is rejection ratiorejection ratio..

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ExampleExample

• In this scenario, even tree routing In this scenario, even tree routing algorithm cannot achieve rejection algorithm cannot achieve rejection ratio.ratio.– Service provider received two VPN Service provider received two VPN

setup requests setup requests vrvr11=(2,3,3) and =(2,3,3) and vrvr22=(3,3,3).=(3,3,3).

– The available bandwidth on all links is The available bandwidth on all links is 5 units.5 units.

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Rejection Ratio of Tree Rejection Ratio of Tree Routing SchemeRouting Scheme

vr2 will be rejected, the rejection ratio achieved is 50%.

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Optimal ArrangementOptimal Arrangement

Both VPN setup requests will be accepted, the rejection ratio achieved is 0%.

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Modified Tree Routing Modified Tree Routing AlgorithmAlgorithm

• The design philosophy of MTRA is The design philosophy of MTRA is to look after both bandwidth to look after both bandwidth allocation efficiency and load allocation efficiency and load balance.balance.– It can reduce rejection ratio It can reduce rejection ratio

effectively.effectively.

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Parameters ConfigurationParameters Configuration

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Yu-Liang Liu 36

Future WorksFuture Works In order to ensure service quality In order to ensure service quality

and availability of VPN services, and availability of VPN services, seamless recovery from failures is seamless recovery from failures is essential.essential.−Failure restoration algorithm for Hose-Failure restoration algorithm for Hose-

Model VPN.Model VPN.

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Recovery from Link Recovery from Link FailureFailure

1 2

3

4

Tree Link (1,4) fail and the corresponding backup path is activated:

Yu-Liang Liu1 On the Bandwidth Management for Hose-Model VPN Service GRADUATE INSTITUTE OF INFORMATION MANAGEMENT NATIONAL TAIWAN UNIVERSITY.

Documents

goal of vpn

adequate bandwidth

yuliang liuthe hose

yuliang liuadvantages

yuliang liumotivation

egress bandwidth requirement

ingress bandwidth requirement

hose model vpnfrom