Mpls Cos Mpls99

8/9/2019 Mpls Cos Mpls99

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1 1999, Cisco Systems, Inc.Course NumberPresentation_ID

MPLS CoSMPLS CoS

Clarence FilsfilsClarence [email protected]@cisco.com


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2 1999, Cisco Systems, Inc.Course NumberPresentation_ID

DiffServ ArchitectureDiffServ Architecture

2Presentation_ID 1999, Cisco Systems, Inc.


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3MPLS99Clarence Filsfils 1999, Cisco Systems, Inc.

DiffServ ArchitectureDiffServ ArchitectureRFC 2475RFC 2475

This architecture achieves scalabilityscalability byimplementing complex classification and

conditioning functions only at network boundarynodes, and by applying per-hop behaviors to

aggregates of trafficaggregates of traffic which have beenappropriately marked using the DS field in the IPv4 orIPv6 headers [DSFIELD]. Per-application flow or per-

customer forwarding state need not be maintainedwithin the core of the network.RFC2475 Architecture for Differentiated Services

This architecture achieves scalabilityscalability byimplementing complex classification and

conditioning functions only at network boundarynodes, and by applying per-hop behaviors to

aggregates of trafficaggregates of traffic which have beenappropriately marked using the DS field in the IPv4 orIPv6 headers [DSFIELD]. Per-application flow or per-

customer forwarding state need not be maintainedwithin the core of the network.RFC2475 Architecture for Differentiated Services


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0. Negociation and agreement of an SLS/TCS

SLS/TCS


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1. Pre-marking in the source domain

- per-application/host basis

- per-default-gateway basis


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2. Egress- boundary DS node of source domainapplies traffic conditioning to ensure SLS/TCScompliance, hence causing possible re-marking,

dropping and shaping

SLS/TCS


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MPLS99Clarence Filsfils 1999, Cisco Systems, Inc.


3. Classification according to SLS

4. Conditioning according to TCS

5. Assignment to a BA (DSCP setting)

SLS/TCS


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6. Forwarding according to PHB mapped to set DSCP


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If downstream DS domain support same serviceprovisioning policy, same PHBs and DSCP/PHB mappings

Then 7: No-op

Else 7a: SLS/TCS negotiation

7b: Conditioning according to TCS

SLS/TCS


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DS fieldDS fieldRFC 2474RFC 2474

DS field replaces IPv4 ToS, IPv6Traffic Class

DSCP = 6 bits : xxxxxx notation

DSCPDSCP CUCUDS fieldDS field


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EF PHB definitionEF PHB definitionRFC2598RFC2598

EF PHB ensures a minimum

departure rate DSCP: 101110

EF PHB can be used to build a low loss, low

latency, low jitter, assured bandwdith, e2eservice through DS domains


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AF PHB definitionAF PHB definitionRFC2597RFC2597

4 independentlyindependently forwarded AF classes

Within each AF class, 3 levels of drop prec01 < 10 < 11, with active Q mgt (RED)

4 independent capacity management plans

AF Class 1: 001dd0

AF Class 2: 010dd0

AF Class 3: 011dd0

AF Class 4: 100dd001: Low Drop

10: Medium Drop

11: High Drop


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AF PHB definition (Cont)AF PHB definition (Cont)

Assured Forwarding (AF) PHB group is a meansfor a provider DS domain to offerdifferent levels ofdifferent levels offorwarding assurances for IP packetsforwarding assurances for IP packets received

from a customer DS domain

Olympic Service (Gold, Silver, Bronze)

gold (C1) >= silver (C2) >= bronze (C3)

No quantifiable timing requirements! delay or delay variation


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AF PHB definition (Cont)AF PHB definition (Cont)

Forwarding assurance of an IP packet:

resources allocated to the AF class

local resource allocation config (buffer andlink BW)

the current load of that AF class conditioning at the DS domain edge

the drop precedence of the packet conditioning at the DS domain edge


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Classifier Conditioner Forwarding PHB Conditioner

Functional Blocks

MeteringDroppingMarkingAccounting

ShapingSchedulingDropping

ACLQPPB

CARTS

Netflow

CEF CBWFQFBWFQWRED

TS

Cisco DiffServ Architecture


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M

PLS99Clarence Filsfils 1999, Cisco Systems, Inc.

MPLS/DiffServ: the obvious fit!MPLS/DiffServ: the obvious fit!Scalability!Scalability!

1000sof flows

MPLS: FEC toLabel Imposition

MPLS: LabelSwitching

DS: PHB basedon DSCP

DS: BehaviorAggregates

DSCPImposition

Different BAs of the same FEC followthe same LSP


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PLS99Clarence Filsfils 1999, Cisco Systems, Inc.

MPLS/DiffServ: the obvious fit!MPLS/DiffServ: the obvious fit!Enhanced ServicesEnhanced Services

1000sof flows

MPLS/DiffServ:per-cos per-FECLabel Impositionwith DHCPimposition

MPLS: LabelSwitching

DS: PHB basedon DHCP

Per-DSCP FEC would allow for newservices (eg. per-CoS TE)


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MPLS/DiffServ: the obvious fit!MPLS/DiffServ: the obvious fit!Enhanced ServicesEnhanced Services

ATM switch runs IP Routing Protocol and IPQoS functions

Ship in the Night Model

More scalability. IP DiffServ intelligence.

IP RoutingIP Routing

LDP SignallingLDP Signalling

VPI/VCI crosstableVPI/VCI crosstable

PNNI RoutingPNNI Routing

UNI/NNI Signal.UNI/NNI Signal.

MPLSStack

ATM ForumStack

IP QoSIP QoS ATMF QoSATMF QoS


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19 1999, Cisco Systems, Inc.

Course NumberPresentation_ID

MPLS DiffServMPLS DiffServ



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Coloring MPLS FramesColoring MPLS Frames

Two methods are possible

Using the EXP bits in the MPLS headerand mapping DSCP to EXP

convenient for Frame-based Interface

Mapping a label per-CoS per-FEC

convenient for ATM-based interface


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Using the EXP bitsUsing the EXP bits

Copy of Precedence into EXP Mapping of DSCP into EXP

IPv4 Packet MPLS Hdr

Prec: xyz Prec: xyzMPLS

EXP: xyz

Non-MPLSDomain

MPLS Domain

0 1 2 30 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Label | EXP |S| TTL |


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IPv4 Packet

Prec: xyz

P/p CoS1 17

P/p CoS2 22

P/p CoS3 25

P/p CoS4 12

Dest-CoS Label

0 1 2 3

0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Label | EXP |S| TTL |

LabelLabel--inferred CoSinferred CoSdraftdraft--ietfietf--mplsmpls--diffdiff--extext--01.txt01.txt

DSCP to Label mapping


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Enforcing PHBs onEnforcing PHBs onnonnon--ATM interfacesATM interfaces



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Frame MPLS CoSFrame MPLS CoSStraightforwardStraightforward

Same Mechanisms as IP CoS

Link Sharer: IOS CBWFQ

Active Q mgnt and differentiated drop: IOS WRED

AF and EF PHBs

Class lookup from either

MPLS CoS/EXP

MPLS Label inferred CoS

Undistinguishable from IPv4 DiffServ


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Enforcing PHBs onEnforcing PHBs onATM interfacesATM interfaces



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ATM MPLS CoSATM MPLS CoSGreat Opportunity!Great Opportunity!

Peer Model!

IP intelligence at every hop

IP-friendly mech. on ATM switches!

Diffserv instead of per-VC ATM QoS

Superior Resource Utilisation

Simpler Resource Allocation

IP RoutingIP Routing

LDP SignallingLDP Signalling

VPI/VCI crosstableVPI/VCI crosstable

PNNI RoutingPNNI Routing

UNI/NNI Signal.UNI/NNI Signal.

IP QoSIP QoS ATMF QoSATMF QoS


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Two ModesTwo Modes

Multi-LSP in TBR mode

Single LSP in ABR mode Each has advantage and drawbacks

TBR: Tag Bit Rate: ATM servicecategory designed for Differv/MPLSTBR: Tag Bit Rate: ATM servicecategory designed for Differv/MPLS


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MultiMulti--VC TBR modeVC TBR modeControlPlaneControlPlane

TDP signals up to 4 parallel LSPs for thesame prefix

CoS LSPs mapping at the edge LSR

Optional setting of CLP (based on DHCP)

Parallel TBR LSPs

ATM LSR


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MultiMulti--VC TBR modeVC TBR modeData PathData Path

Edge LSR:

per CoS WFQ + per CoS WRED

ATM-LSR

per CoS WFQ + per CoS WEPD

NO per-LVC management!!!

Scalability and better muxing

Parallel TBR LSPs

ATM LSR


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MultiMulti--VC TBR modeVC TBR modeExampleExample

Queuing on all links is per-class WFQ (not per LSP)

Resource allocation

Assign weight to each class on per-link basis(e.g. Premium gets 80% of link, Standard gets 20%) Choice of weights based on expected load & desired

performance PER CLASS No per-router-pair configuration (config independent of

topology & geography)

Per COSWFQ


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Clarence Filsfils 1999, Cisco Systems, Inc.

Single `VC ABR modeSingle `VC ABR mode

1 single LVC per FEC

ABR control algorithms are enabled on LSPs

Extention ofIPATMCoS feature

ATM-LSRs push congestion towards edge LSRs

Edge-LSRs: WRED/WFQ per-LSP queues

ABR LSP

ATM LSR


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Single VC ABR modeSingle VC ABR mode

ATM-LSR Scheduling = per-VC ABR

ABR parameters:

MCR is effectively zero (to avoidloss/blocking)

Relative bandwidthRelative bandwidth parameter

carried by TDP and used by ABRalgorithm


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SingleSingle--ABR vs MultiABR vs Multi--TBRTBR

Multi-VC TBR Mode:

Congestion managed directly at every hop (IP and ATM hops)

Possible Discard at every hop

Resource Allocation per COS per link; does not have to concernitself with topology and geography

Single-VC ABR:

No Loss in the ATM fabric

Discard/Scheduling possible only on the Edge performed byRouters

Resource Allocation optionally per Pair of Edge Routers.


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MPLS99


MPLS over ATMF PVCMPLS over ATMF PVCA specialCaseA specialCase

Generic Frame MPLS CoS Case!

A Frame LSR uses ATM-F PVC with chosen ATM QoS

Service Differentiation on Frame LSRs at edge of ATM

Use IPATMCoS featuresIPATMCoS features!

ATM Forum PVCATM Forum PVC

LDPLDP

ATM Forum ATMATM Forum ATM


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MPLS99


MPLS over IPATMCoSMPLS over IPATMCoSperper--VC IP QoSVC IP QoS

Congestion pushed back at the edge

ATMATM--F service classF service classenforcedenforced

perper--VC ATMVC ATM--F shapingF shaping CBWFQ/WRED on IPCBWFQ/WRED on IP

perper--VC QueueVC Queue


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MPLS over IPATMCoSMPLS over IPATMCoSBundle IP QoSBundle IP QoS

ATMATM--F service classF service classenforcedenforced

perper--VC ATMVC ATM--F shapingF shaping DSCP to VC mappingDSCP to VC mapping WRED on IP perWRED on IP per--VC QVC Q

1! IGP adajacency1! IGP adajacency


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Course Number

Presentation_ID

MPLS VPN CoSMPLS VPN CoS



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MPLS VPN QoS ArchitectureMPLS VPN QoS Architecture

2 very distinct point of views:

How the SP will market the service (SLA)

What are the mechanisms for SP to meet thecommitments/SLA

FR analogy:

sell 64 kb/s CIR for 99.5% of the time

reserve 64/overbooking kb/s + admission control+ selective discard +


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How to market MPLS VPN CoS?How to market MPLS VPN CoS?ICR conceptICR concept -- hose modelhose model

VPNSP

VPN_Asite 2

VPN_Asite 3

ICR256k

ICR256k

ICR512k

ECR128k

ECR128k

ECR512k

VPN_Asite 4

Hose Model (point-to-multipoint commodity)Draft-duffield-vpn-qos-framework.txt, AT&T


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Proposed SLA for CoS C1Proposed SLA for CoS C1

As long as for each site S of VPN X:

S sends less than ICR

S receives less than ECR(optional: double-ended SLA)

Then:

loss property is 10^(-n1)

RTT is < m1 ms


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Extensible to multiple CoS!Extensible to multiple CoS!

CoS X: [nx, mx], price Px

Gold: [-10, 100ms], $$$

Silver: [-8, 200ms], $$

BE: [be, be], $


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Should not be marketed as Frame Relay QoS:

N1 kb/s guaranteed from Site 1 to Site 2

N2 kb/s guaranteed from Site 1 to Site 3 N3 kb/s guaranteed from Site 2 to Site 3

Layer 2 based VPNs (ie FR or ATM) address

that need

How it should not be marketedHow it should not be marketed


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Any to any connectivity

Without requiring the customer to have a

precise and complete knowledge of its trafficmatrix

Matrix of ICR/ECR allows the provider tobetter engineer his network (hence, to lower

the cost of the commodity) Per-usage billing is still possible (ICR/ECR

then only serve as boundaries)

Advantage of this SLA modelAdvantage of this SLA model


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How to meet SLAHow to meet SLA

Enforcement of ICR:

CAR: policing in/out of profile

Enforcement of ECR

CAR/TS

MPLS CoS in the SPs backbone

single-ABR, multi-TBR mode

DiffServ engineering


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DiffServ EngineeringDiffServ Engineering

Scalability: no per-VPN QoS in BB!!!

This is a pure diffserv design!

Per-Class Scheduling/Discarding at every hop

Resource Allocation based on ICR/ECR sold

share each trunk between different Classes

start conservative

then monitor traffic per class and fine tune

Optimise with per-class Traffic Engineering

Cisco Service Management tool forTag VPN QoSprovisioning


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Course Number

Presentation_ID

DiffServ EngineeringDiffServ EngineeringCapacity ManagementCapacity Management



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DiffServ ArchitectureDiffServ ArchitectureThe Service OfferThe Service Offer

1. The routing topology

2. The speed of the links

3. The link sharing ratios

(CBWFQ %)

THE Service Offer


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DiffServ ArchitectureDiffServ ArchitectureThe Service DemandThe Service Demand

1. The matrix of ICR

2. The matrix of ECR

THE Service Demand


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DiffServ ArchitectureDiffServ ArchitectureThere is no magicThere is no magic

Service Offer (per class) >= ServiceDemand (per class)

How to achieve this?

provisioned QoS


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Connectionless DifficultyConnectionless Difficulty

Temporal gambling (of course) In a connectionless world (eg, IP),

this provioning is more complex:

spacial gambling!


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Temporal GamblingTemporal GamblingSame as in ATM/FRSame as in ATM/FR

The path is known (connection-oriented)

The gamble is done on the TEMPORAL traffic

distribution

The red and green dlcis should not be loaded atthe same time

FR PVC, CIR =48kbps

FR PVC, CIR =

48kbps

Trunk is 64kbps


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Spacial GamblingSpacial Gambling

The path is NOT known. The destination is notknown (anycast service)

The gamble is done on the SPACIAL (andtemporal) traffic distribution


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Offer >= DemandOffer >= Demand

There are three models

1. Huge Over-provisionning

2. Constant Monitoring andreprovisioning

3. = 2 + Per-CoS Traffic Engineering


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Offer >> DemandOffer >> Demand

Backbone has lots of BW

QoS is only enforced at the edge


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PerPer--CoS MPLS TrafficCoS MPLS TrafficEngineeringEngineering

Monitor the POP to POP matrix per CoS

eg.: for yesterday peak rates

At 00h00, provision POP to POP per-CoSMPLS tunnels for 110% ofmax(yesterdays peek, 7-days agos peek)

Optimization could be every hour, every 15-minutes


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PerPer--CoS MPLS TrafficCoS MPLS TrafficEngineeringEngineering

MPLS per-CoS TE is an additional tacticaltool that allows you to master the space

gambling just as in connection-orientednetworks

Benefit of:

MPLS for tunnelization RRR for Constraint based routing

RSVP for resource reservation


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Course Number

Presentation_ID

MPLS VPN QoSMPLS VPN QoSPipe ModelPipe Model



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MPLS VPN QoS: hose modelMPLS VPN QoS: hose modelRememberRemember

Relies on Diff-Serv model supported over MPLS

provides statistical guarantees to each Diff-Serv Class/Servicein the Hose Model (Provisioned QoS)

customer does not have to know/specify his traffic matrix,

change inside traffic matrix accommodated by SP withoutchange in the hose contract

offers Diff-Servs benefits in scalability (can be deployed on anynumber of VPN Sites, does not require any increase in numberof labels, ...)

offers Diff-Servs benefits in simplicity (can be deployedimmediately)

! The model for 95% of the VPNs !


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PIPE model for special sitesPIPE model for special sitesGuaranteed BandwidthGuaranteed Bandwidth

5 Mb/s

1 Mb/sVPN GreenVPN Green

HQ1HQ1

VPN GreenVPN GreenHQ backHQ back--upup

VPN Green,100s of branches,each with n kb/s ofIngress Committed Rateinto a Diff-Serv Class

BandwidthGuarantees

MPLS VPN


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Guaranteed PIPE ModelGuaranteed PIPE Model

The QoS benefits of Virtual Leased Line

per-PIPE guarantee

Maintain Scalability Aggregation via DiffServ and MPLS

Scalable Admission Control

RSVP aggregation

Optimization of Resource Usage

Traffic Enginering and RRR


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Course Number

Presentation_ID

MPLS QoSMPLS QoSConclusionConclusion



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MPLS QoSMPLS QoSEnable enhanced servicesEnable enhanced services

Same QoS support as IP

DiffServ, IntServ support

Plus Extra functionality

MPLS-CoS over ATM in peer model(multi-vc TBR feature)

Traffic Engineering and RRR with per-CoSextensions

MPLS-VPN CoS (hose + pipe)


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Mpls Cos Mpls99