1 © 2001, Cisco Systems. MPLS-QoS Jay Kumarasamy [email protected].

1© 2001, Cisco Systems.

MPLS-QoSMPLS-QoS

Jay [email protected] [email protected]

22001 Cisco Systems, Inc.

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AgendaAgenda

• QoS Models

• Differentiated Model Features

• Modular QoS CLI (MQC)

• MPLS QoS

• Sample Examples


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QoS ModelsQoS Models

• Integrated Services (IntServ)

• Differentiated Services (Diffserv)


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No state

Best Effort

Per-flow state

IntServ / RSVP

Aggregatedstate

D iffServ

1. T he orig inal IP service

2. F irst efforts at IP Q oS

3. Seeking simplic ity and scale

4. Bandw idth O ptim ization & e2e SLAs((IntServ +DiffServ+ T raffic Engineering))

Time

The QoS PendulumThe QoS Pendulum


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Integrated ModelIntegrated Model

• Application requests a specific kind of QoS service, through explicit signaling.

• Resource Reservation Protocol (RSVP) is used by applications to signal their QoS requirements to the router.

• Complex to use.

• Difficult to support with a large number of RSVP connections, due to:

the amount of state information required for every flow.

the amount of control traffic

• Fine grain, providing strict QoS.


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Differentiated Model Differentiated Model

• Qos is provided by differential treatment to each packet or class of packets.

• No explicit signaling from the application.

• This model is appropriate for aggregate flows.

• Coarse grain, not strict QoS (no guarantees).


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Differentiated IP Services

Guaranteed: Latency and Delivery

Best Effort Delivery

Guaranteed Delivery

Voice

E-mail, WebBrowsing

E-Commerce

Application Traffic

Platinum Class Low Latency

Silver

Bronze

Gold

VoiceVoice

TrafficClassification

TrafficClassification

Differentiated Model Divide Traffic into ClassesDifferentiated Model

Divide Traffic into Classes


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SwitchingFabric

rx queue tx queue

tx hwrecv hw

Differentiated ModelDifferentiated Model

Classification/Marking policy

Droppolicy

Schedulingpolicy


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AgendaAgenda

• QoS Models



• MPLS QoS

• Sample Examples


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Differential Model FeaturesDifferential Model Features

• Classification

• Marking

• Policing and Shaping

• Congestion Avoidance

• Congestion Management


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Differentiated Model Features Classification

Differentiated Model Features Classification

Most fundamental QoS building block

The component of a QoS feature that recognizes and distinguishes between different traffic streams

Without classification, all packets are treated the same


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Differentiated Model Features Marking

Differentiated Model Features Marking

VersionVersionLengthLength LenLen

Layer 3IPV4

Layer 3IPV4

IDID OffsetOffset TTLTTL ProtoProto FCSFCS IP-SAIP-SA IP-DAIP-DA DataDataToSToS

1 Byte1 Byte

07 123456

IP Precedence

DSCP

Unused Bits;

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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Differentiated Model Features Policing and Shaping

Differentiated Model Features Policing and Shaping

• Policing is the QoS component that limits incoming traffic flow to a configured bit rate

• Shaping is the QoS feature component that regulates outgoing traffic flow to a configured bit rate


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Differentiated Model Features Congestion Avoidance

Differentiated Model Features Congestion Avoidance

Drop Policy

• Tail Drop

• Random Early Detection (RED)

• Weighted Random Early Detection (WRED)


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Differentiated Model Features Congestion Management

Differentiated Model Features Congestion Management

Scheduling Policy

• FIFO

• Fair Queuing

• Weighted Fair Queuing (WFQ)

• Class Based Weighted Fair Queuing (CBWFQ)

• Low Latency Queuing (LLQ)


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AgendaAgenda

• QoS Models



• MPLS QoS

• Sample Examples


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Modular QoS CLIModular QoS CLI

Modular QoS CLI (MQC)

Command syntax introduced in 12.0(5)T

Reduces configuration steps and time

Uniform CLI across all main Cisco IOS-based platforms

Uniform CLI structure for all QoS features


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Basic MQC CommandsBasic MQC Commands

class-map [match-any | match-all] class-name

router(config)#

• 1. Create Class Map - a traffic class ( match access list, input interface, IP Prec, DSCP, protocol (NBAR) src/dst MAC address, mpls

exp).

policy-map policy-map-name

router(config)#

• 2. Create Policy Map (Service Policy) - Associate a

class map with one or more QoS policies (bandwidth, police, queue-

limit, random detect, shape, set prec, set DSCP, set mpls exp).

service-policy {input | output} policy-map-name

router(config-if)#

• 3. Attach Service Policy - Associate the policy map with an input or output interface.


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• 1. Create Class Map

Router(config)# class-map class1Router(config-cmap)# match ip precedence 5Router(config-cmap)# exit

Router(config)# policy-map policy1Router(config-pmap)# class class1Router(config-pmap-c)# set mpls experimental 5Router(config-pmap-c)# bandwidth 3000 Router(config-pmap-c)# queue-limit 30Router(config-pmap)# exit

Router(config)# interface e1/1Router(config-if)# service-policy output policy1 Router(config-if)# exit

• 2. Create Policy Map

• 3. Attach Service Policy

Basic MQC CommandsBasic MQC Commands


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AgendaAgenda

• QoS Models



• MPLS Quality of Service

• Sample Examples


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ConventionalRouter

Label EdgeRouters

ATM-LSR

Label SwitchingRouter (LSR)

• Note: End to end service is IP; therefore, IP class of service is what MPLS must support

MPLS QoSMPLS QoS


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ISP Customer

MPLS

3) Invoke QoS Policy Action Based on EdgeClassification (based on MPLS EXP), e.g. LLQ,CBWFQ, Drop PolicyLow Priority via WRED if rate limit exceeded

1) Packet Classificationthrough IP Prec/DSCP

2) Match IP Prec/DSCP; Set MPLS EXP.Rate-limit/Police and apply drop policy

Core

MPLS QoSMPLS QoS


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MPLS QoSMPLS QoS

• ‘Differentiated Model’ approach: Set IP precedence or MPLS Exp bit at the edge of the network

• WRED by MPLS Exp, and WFQ by class in the core

• Because MPLS is there primarily to transport IP, MPLS’s primary QoS goal is to support existing IP QoS models

• Because MPLS is there to support very large scale operations, MPLS should also be capable of supporting Diff-Serv in the future


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MPLS QoSMPLS QoS

• Copy of IP Precedence into MPLS EXP

• Mapping of IP Precedence into MPLS EXP

Prec: xyz

IPv4 Packet MPLS Hdr

Prec: xyzMPLS EXP: xyz

Non-MPLS Domain

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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MPLS QoSDiff-Serv : Jargon

MPLS QoSDiff-Serv : Jargon

• PHB = Per Hop BehaviorThe Diff-Serv treatment (scheduling/dropping) applied by a Router to all the packets which are to experience the same Diff-Serv service

• DSCP = Differentiated Services Code PointThe value in the IP Header indicating which PHB is to be applied to the packet

• BA = Behavior AggregateThe set of all the packets which have the same DSCP (and thus that will receive the same PHB)

• OA = Ordered AggregateThe set of BAs which have an ordering constraint (“must go into the same queue”)

• PSC = PHB Scheduling ClassThe set of PHBs applied to an OA (the set of PHBs using the same queue”)


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MPLS QoSDiff-Serv : DSCP

MPLS QoSDiff-Serv : DSCP

1 0 1 1 1 0DSCPDSCP

CUCUEFEF

x x x y y 0DSCPDSCP

CUCUAFxyAFxy

ClassClass DropDrop

PrecedencePrecedence

AF Class = 1, 2, 3, 4AF Class = 1, 2, 3, 4 Drop Precedence = 2, 4, 6Drop Precedence = 2, 4, 6


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MPLS QoS Diff-Serv over MPLS

MPLS QoS Diff-Serv over MPLS

• Two methods:

E-LSP

“Queue” inferred from Label and EXP field

“drop priority” inferred from label and EXP field

L-LSP

“Queue” inferred exclusively from Label

“drop priority” inferred from EXP field

<draft-ietf-mpls-diff-ext-03.txt>, by Francious Le Faucheur, et al


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MPLS QoS E-LSP Example

MPLS QoS E-LSP Example

• E-LSPs can be established by various label binding protocols (LDP or RSVP)

• Example above illustrates support of EF and AF1 on single E-LSP

Note: EF and AF1 packets travel on single LSP (single label) but are enqueued in different queues (different EXP values)

• Queue is selected based on EXP

E-LSP

LSRLDP/RSVP LDP/RSVP

EFAF1


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MPLS QoSL-LSP Example

MPLS QoSL-LSP Example

• L-LSPs can be established by various label binding protocols (LDP or RSVP)

• Example above illustrates support of EF and AF1 on separate L-LSPs

EF and AF1 packets travel on separate LSPs and are enqueued in different queues (different label values)

• Queue is selected based on label, Discard is based on ESP

L-LSPs

LSR

LDP/RSVP LDP/RSVP


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MPLS QoSEdge DiffServ LSR with L-LSP

MPLS QoSEdge DiffServ LSR with L-LSP

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 |

IPv4 Packet MPLS Header

Non-MPLS Diff-Serv Domain

MPLS Diff-Serv Domain

DSCP

Edge LSR

1) identify incoming packet’s BA looking at incoming DSCP2) pick the LSP/label which supports the right FEC and the right BA3) mark the EXP field to reflect the packet’s BA

DSCP


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MPLS QoSSignaling

MPLS QoSSignaling

• E-LSPs can be set up with existing (non-DS-aware) signalling

LDP, RSVP etc.

EXP -> PHB mapping is configured on every router as per Diffserv

• L-LSPs require signalling extension to bind “queue” to a label

New DIFFSERV object/TLV added to RSVP/LDP to signal the “queue” in which to enqueue the label

Meaning of EXP bits is well-known (ie standardised for each PSC)


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MPLS QoSE-LSP & L-LSP Applicability

MPLS QoSE-LSP & L-LSP Applicability

• MPLS over PPP and LAN:

both E-LSPs and L-LSPs are applicable

• MPLS over ATM:

only L-LSPs possible (EXP is not seen by ATM LSR)


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MPLS QoSMPLS QoS

• On non-ATM LSRs, MPLS-QoS is simple

• Copy or Map IP precedence to MPLS exp field

• Exact same mechanism as IP-QoS

• Net result is end-to-end QoS indistinguishable from non-MPLS (IP) network


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MPLS QoSMPLS QoS

MPLS QoS on ATM-LSRs

Two Challenges: No WRED in switches

No EXP field in header

Solution Modes: ATM Forum PVC

Multi VC (LSP)


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MPLS QoS ATM Forum PVC Mode

MPLS QoS ATM Forum PVC Mode

• Looks like packet interface to MPLS QoS

• BW and other parameters configured on the PVC

• Requires significant amount of configuration

ATM-LSR

PVC


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MPLS QoS Multi VC Mode


ATM-LSRMPLS LVCs

• MPLS ATM core provides MPLS QoS at each link

• Configure each non-ATM LSR to support a number

of classes (2-4)

• Parallel LVCs automatically established

• Assign weight to each class


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• Queuing is done through CBWFQ (eg. Premium gets 80% of link, standard gets 20%)

• Unused bandwidth available to other classes

• No per-router-pair configuration required, as in ATM Forum PVC


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AgendaAgenda

• QoS Models



• MPLS Class of Service

• Examples


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ExamplesExamples

PE 2

Pos 1/0

PE 3

MPLS Network

PE 1

PE 4

CE 4

CE 2

PE 5

CE 1

CE 3Pos 1/1

Pos 5/0

Pos 4/0

Pos 2/0

P 3


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ExamplesExamples

! Matching voice traffic from customer 1Pe1(config)# class-map match-all cus1_voicePe1(config-cmap)# match interface POS1/0Pe1(config-cmap)# match ip precedence 4Pe1(config-cmap)# end ! Matching voice traffic from customer 2Pe1(config)# class-map match-all cus2_voicePe1(config-cmap)# match interface POS1/1Pe1(config-cmap)# match ip precedence 5Pe1(config-cmap)# end ! Matching any e2e trafficPe1(config)# class-map erpPe1(config-cmap)# match ip precedence 2Pe1(config-cmap)# end


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ExamplesExamples

Pe1(config)# class-map isp_voicePe1(config-cmap)# match mpls experimental 4Pe1(config-cmap)# end Pe1(config)# class-map isp_erpPe1(config-cmap)# match mpls experimental 2Pe1(config-cmap)# end Pe1(config)# class-map isp_routinePe1(config-cmap)# match mpls experimental 1Pe1(config-cmap)# end


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ExamplesExamples

! Input Policy for setting experimental 4, 2, 1

Pe1(config)# policy-map pe1_inputPe1(config-pmap)# class cus1_voicePe1(config-pmap-c)# set mpls experimental 4Pe1(config-pmap-c)# exitPe1(config-pmap)# class cus2_voicePe1(config-pmap-c)# set mpls experimental 4Pe1(config-pmap-c)# exitPe1(config-pmap)# class erpPe1(config-pmap-c)# set mpls experimental 2Pe1(config-pmap-c)# exitPe1(config-pmap)# class class-defaultPe1(config-pmap-c)# set mpls experimental 1Pe1(config-pmap)# exit


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ExamplesExamples

! Output Policy for configuring bandwidth, queue…

Pe1(config)# policy-map policy pe1_outputPe1(config-pmap)# class isp_voicePe1(config-pmap-c)# priority 100Pe1(config-pmap-c)# exitPe1(config-pmap)# class isp_erpPe1(config-pmap-c)# bandwidth 50Pe1(config-pmap-c)# queue-limit 30Pe1(config-pmap-c)# exitPe1(config-pmap)# class class-defaultPe1(config-pmap-c)# bandwidth 20Pe1(config-pmap-c)# queue-limit 100Pe1(config-pmap-c)# exitPe1(config-pmap)# exit


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ExamplesExamples

Pe1(config)# interface POS1/0Pe1(config-if)# service-policy input pe1_input Pe1(config)# interface POS1/1Pe1(config-if)# service-policy input pe1_input Pe1(config)# interface POS2/0Pe1(config-if)# service-policy output pe1_output


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ExamplesExamples

PE 2

Pos 1/0

PE 3

MPLS Network

LC-ATM

PE 4

CE 4

CE 2

PE 5

CE 1

CE 3

Pos 1/1

Pos 5/0

Pos 4/0

ATM Core

PE 1LSC1


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Pe1(config)# ATM1/0Pe1(config-if)# no ip addressPe1(config-if)# atm clock INTERNALPe1(config-if)# no atm ilmi-keepalivePe1(config-if)# exit Pe1(config)# interface ATM1/0.1 tag-switchingPe1(config-if)# ip unnumbered loopback0Pe1(config-if)# tag-switching multi-vcPe1(config-if)# tag-switching atm vpi 2-5Pe1(config-if)# tag-switching ip ! Sets up 3 LVCs.Pe1(config)# cos-map 1 ! 3 - standardPe1(config-mpls-cos-map)# class 3 standard ! 2 - premiumPe1(config-mpls-cos-map)# exit ! 1 - standard ! 0 – availablePe1(config)# mpls prefix-map 1 access-list 1 cos-map 1

ExamplesExamples


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ExamplesExamples

! Matching voice traffic from customer 1Pe1(config)# class-map match-all cus1_voicePe1(config-cmap)# match interface POS1/0Pe1(config-cmap)# match ip precedence 4Pe1(config-cmap)# end ! Matching voice traffic from customer 2Pe1(config)# class-map match-all cus2_voicePe1(config-cmap)# match interface POS1/1Pe1(config-cmap)# match ip precedence 5Pe1(config-cmap)# end ! Matching any e2e trafficPe1(config)# class-map erpPe1(config-cmap)# match ip precedence 2Pe1(config-cmap)# end


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ExamplesExamples

P! Input Policy for setting experimental 2, 1, 0e1(config)# policy-map pe1_inputPe1(config-pmap)# class cus1_voicePe1(config-pmap-c)# set mpls experimental 2 ! Voice for customer 1Pe1(config-pmap-c)# exitPe1(config-pmap)# class cus2_voicePe1(config-pmap-c)# set mpls experimental 2 ! Voice for customer 2Pe1(config-pmap-c)# exitPe1(config-pmap)# class erpPe1(config-pmap-c)# set mpls experimental 1 ! ERP dataPe1(config-pmap-c)# exitPe1(config-pmap)# class class-defaultPe1(config-pmap-c)# set mpls experimental 0 ! All other trafficPe1(config-pmap)# exit Pe1(config)# class-map isp_voicePe1(config-cmap)# match mpls experimental 2Pe1(config-cmap)# end


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ExamplesExamples

Pe1(config)# class-map isp_erpPe1(config-cmap)# match mpls experimental 1Pe1(config-cmap)# end Pe1(config)# class-map isp_availablePe1(config-cmap)# match mpls experimental 0Pe1(config-cmap)# end ! Output Policy for configuring bandwidth, queue…Pe1(config)# policy-map policy pe1_outputPe1(config-pmap)# class isp_voicePe1(config-pmap-c)# priority 100


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ExamplesExamples

Pe1(config-pmap-c)# exitPe1(config-pmap)# class isp_erpPe1(config-pmap-c)# bandwidth 50Pe1(config-pmap-c)# queue-limit 30Pe1(config-pmap-c)# exitPe1(config-pmap)# class isp_availablePe1(config-pmap-c)# bandwidth 20Pe1(config-pmap-c)# queue-limit 100Pe1(config-pmap-c)# exitPe1(config-pmap)# exit


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ExamplesExamples

LSC1

Interface XTagATM11 extended-port ATM3/0 bpx 1.1 tag-switching atm vpi 2-15 tag-switching atm cos available 20 tag-switching atm cos standard 30 tag-switching atm cos premium 50 tag-switching ip Interface XTagATM12 extended-port ATM3/0 bpx 1.2 tag-switching atm vpi 2-15 tag-switching atm cos available 20 tag-switching atm cos standard 30 tag-switching atm cos premium 50 tag-switching ip


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Thank You!Thank You!

1 © 2001, Cisco Systems. MPLS-QoS Jay Kumarasamy [email protected].

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Transcript of 1 © 2001, Cisco Systems. MPLS-QoS Jay Kumarasamy [email protected].