Copyright 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 1. IPS _05_2001_c1_X

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IPS-231 3141_05_2001_c1_X

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IPS-231 3141_05_2001_c1_X

Deploying QoS in Service

Provider Networks

Session IPS-231

3141_05_2001_c1_X

Agenda

• QoS Introduction

• Deployment Guide

• Configuring QoS in IOS

• Case Studies

(3)

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Motivation Behind QoS

• Applications are sensitive to delay, jitter and

packet loss

• There are non-adjustable components (e.g.

propagation delay, switching delay, CRC errors)

• There are adjustable components associated

with link congestion (buffering delay and

packet loss)

• Some Congestion is likely in most networks

• Service provider can manage situation and offer

value-added service

Over-Provisioning Is NOT the Solution

• Engineering department may

over-provision inter/intra

POP links

• However, customer and

sales department define site

to POP links

• Provider CANNOT generally

solve

end-to-end

QoS for

its customers with

over-provisioning

(4)

Congestion Scenarios

CE CE 2 Mbps 1 Mbps Speed Mismatch 1 Mbps 1 Mbps 1 Mbps 1 Mbps 1 Mbps 4 Mbps Traffic Aggregation CE CE CE 1 Mbps 1 Mbps 1 Mbps Traffic Aggregation

© 2001, Cisco Systems, Inc. All rights reserved. 888 IPS-231 3141_05_2001_c1_X Time 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 Time 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 100% Time 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 Link

Utilization

• Link over-provisioned

• May not be cost effective

• No QoS required but a

safety net

100% Link Utilization 100% Link Utilization

• Transient congestion

• QoS most useful

• Link highly over-subscribed

• QoS somewhat useful but more

bandwidth required

(5)

© 2001, Cisco Systems, Inc. All rights reserved. 999 IPS-231 3141_05_2001_c1_X Classification Identify and split traffic into different classes Prioritize, protect and isolate traffic Mark traffic if necessary Policing Marking Queuing & Dropping Shaping Discard misbehaving traffic to maintain network integrity Control bursts and conform traffic

How does a router implement different

qualities of service?

QoS Building Blocks

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Classification Policing _Marking Queuing &

Dropping Shaping

Classification

• Classification identifies groups of packets that

will receive a particular service

• Traffic gets classified using layer-2 and above

• The actual classification criteria may vary at

different points (e.g. ACL, destination, DSCP, etc.)

(6)

Policing

• Some traffic may be restricted to a certain rate

• Excess packets may be dropped or given a

special marking (dropping precedence)

Marking

Classification Policing Marking Queuing & Dropping Shaping

• Carries information about packet class, dropping

precedence or both

• Simplifies classification inside the network

• May be tied to policing

• Layer 2 and layer 3 specific (e.g. FR DE, ATM CLP, 802.1p/q,

IP DSCP, IP Precedence, MPLS Experimental field)

(7)

Queuing

• Queues protect and isolate traffic

• Each output queue receives an allocation of bandwidth

and buffers

• One queue may be reserved for low latency traffic

(e.g. VoIP)

• Several implementations (e.g. CBWFQ, LLQ, MDRR)

Dropping

• By default, packets arriving at the queue are dropped at the

tail if queue is full (tail drop)

• Packets in a queue may have different dropping precedence

values and a dropping policy may be desirable

• WRED allows you to define a dropping policy and

randomizes drops

(8)

Shaping

Classification Policing _Marking Queuing & Dropping Shaping

• Traffic is restricted to a certain rate as with policing

• Excess packets are queued, not dropped or marked as

with policing

• Generally applied to smooth traffic and prevent drops

by upstream/downstream policing

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IP QoS Architectures

• There are two QoS architectures for IP

• Integrated Services (IntServ)

(9)

© 2001, Cisco Systems, Inc. All rights reserved. 171717 IPS-231 3141_05_2001_c1_X Handset PBX Cisco 7200 Cisco 7200 Multimedia Server Handset Cisco 3600 Reserve 16K BW on this Line I Need 16K BW and 100 msec Delay This App Needs

16K BW and 100 msec Delay Multimedia Station

Integrated Services

• Signaled QoS

• Per-flow QoS

• Soft-state

maintained at

every node

• Resource admission

control

• Policy admission

control

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Differentiated Services

• Provisioned QoS

• Per-flow-aggregate QoS

• No state maintained in the network

• No resource admission control

(10)

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Traffic Classification and Conditioning Classification/Marking/Policing Per-Hop Behavior (PHB) Queuing/Dropping Ingress Node Interior Node Egress Node TC PHB PHB TC PHB

Differentiated Services Architecture

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Expedited Forwarding

Per-Hop Behavior (PHB)

• Building block for low delay, low jitter

and low loss services

• Packets marked for EF should encounter

short or empty queues and traffic be

served at a certain rate

(11)

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Assured Forwarding

Per-Hop Behaviors (PHB)

• Packets are forwarded with high

probability if they don’t exceed the

subscribed information rate (profile)

• Four classes with four different levels

of forwarding assurance and three

levels of drop precedence

• The node allocates a certain amount

of forwarding resources (buffer space

and bandwidth) to each class

1 0 1 1 1 0

EF

x x x y y 0

AFxy

Class

Class _Drop_Drop

Precedence Precedence

0 0 0 0 0 0

BE

IP Packet

Data

PHB Recommended Codepoints

(12)

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IntServ vs. DiffServ

• DiffServ is less granular (aggregates), scales

to large number of application flows

• IntServ is more granular (per-flow), scales to

a smaller number of application flows

• IntServ has some desirable characteristics

(e.g. admission control)

• DiffServ is the preferred QoS architecture

for Service Providers today

• A full end-to-end solution in the future is

very likely to incorporate both

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What about MPLS?

• MPLS can support both IntServ

and DiffServ

• MPLS support for DiffServ being

standardized (draft-ietf-mpls-diff-ext)

(13)

PPP Header Layer 3 HeaderLayer 3 Header

PPP Header

(Packet over SONET/SDH)

Label Header Label Header MAC Header

MAC Header Layer 3 HeaderLayer 3 Header

LAN MAC Label Header

ATM Cell Header

HECHEC

Label Label DATA DATA CLP CLP PTI PTI VCI VCI GFC GFC VPIVPI

How to define codepoints on an MPLS packet?

MPLS Encapsulations

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Label 20 bits

EXP Experimental Field, 3 bits

S Bottom of Stack, 1 Bit

TTL Time to Live, 8 Bits

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

Label Header for Packet Media

• Can be used over other layer-2 technologies

• Contains all information needed at forwarding time

• One 32-bit word per label

(14)

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DiffServ Marking of MPLS Packets

• How DiffServ information is conveyed to LSRs?

E-LSP

(Cisco IOS 12.1(5)T, 12.0(11)ST)

“Queue” inferred from Label and EXP field

“Drop priority” inferred from label and EXP field

L-LSP

(Currently only available on ATM-LSRs)

“Queue” inferred exclusively from Label

“Drop priority” may be inferred from EXP field

MPLS Traffic Engineering with QoS

• Traffic is routed using

explicit and

constrain-based routing

• Aggregate admission

control against a particular

bandwidth pool

• Packets are scheduled at

every hop according to EXP

marking regardless of LSP

(15)

MPLS VPNs with QoS

• Per-VPN QoS policies

at the edge

• Same MPLS QoS policies

for packets of all VPNs

in the core

• QoS can be implemented

with site-to-network guarantees

• QoS can also be implemented

with site-to-site

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Agenda

• QoS Introduction

• Deployment Guide

• Configuring QoS in IOS

• Case Studies

(16)

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Deployment Guide

• Step 1: Define business model

• Step 2: Identify applications and

requirements

• Step 3: Define policies

• Step 4: Test policies

• Step 5: Apply policies

• Step 6: Monitor and adjust

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How Can We Generate Additional Revenue?

Deployment Guide

Step 1: Business Model

• Utility model

• Subscription model

(17)

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Deployment Guide

Step 2: Identify Applications

• Real-Time Conversational (e.g. VoIP)

• Real-Time Streaming (e.g. Real Video)

• Interactive Class (e.g. HTTP, Telnet)

• Background/Bulk (e.g. FTP, Dbase Synch.)

3141_05_2001_c1_X

Deployment Guide

Step 3: Network Assessment

• Network topology and traffic flow

• Capacity of your network devices (CPU,

software, etc.)

• Capacity of your network links (speeds,

overhead, congestion, etc.)

(18)

© 2001, Cisco Systems, Inc. All rights reserved. 353535 IPS-231 3141_05_2001_c1_X Real -Time Interactive Real -Time Streaming Interactive Background and Bulk Best Effort Marking Queuing Dropping

EF AF3 AF2 AF1 Default

priority 512 Tail drop bandwidth percent 25 Tail drop bandwidth percent 20 WRED bandwidth percent 10 WRED Available WRED Policing 512k 256k 128k 128k None

Define QoS Policies at Each Hop,

for Instance:

Deployment Guide

Step 4: Define Policies

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Deployment Guide

Step 5: Test Policies

• Test in the lab first

• Baseline your applications

(19)

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Deployment Guide

Step 6: Apply Policies

• Police and mark as early as possible

• Work toward your core applying

inbound/outbound policies

• Apply your policies incrementally

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Deployment Guide

Step 7: Monitor and Adjust

• Measure delay and loss for

different classes

• Monitor application performance

(20)

Agenda

• QoS Introduction

• Deployment Guide

• Configuring QoS in IOS

• Case Studies

• References

3141_05_2001_c1_X

Configuring QoS in IOS

Modular QoS CLI (MQC)

• Template-based command syntax for QoS

• Separates classification engine from

the policy

• Uniform CLI for QoS features

(21)

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policy-map

policy-name

Enters configuration sub-mode for policy definition

(marking, policing, shaping, queuing, etc.)

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

class-name

Enters configuration sub-mode for class definition

service-policy {input | output}

policy-name

Command in interface configuration sub-mode to

apply QoS policy for input or output traffic

Configuring QoS in IOS

MQC Abstractions and Syntax

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set {ip | mpls | cos | atm-clp | … }

police avg-rate Bc Be conform-action action exceed-action action violate-action action

shape {average | peak}

cir

[

bc

] [

be

]

priority {percent percentage | bandwidth-kbps}

or

bandwidth {percent

percentage

| bandwidth-kbps}

random-detect [dscp | dscp-based | … ]

Configuring QoS Policies in IOS

QoS Building Blocks

(22)

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QoS Policy Propagation via BGP

• Allows you to define a mapping between

a prefix, community or as-path to IP

precedence value or qos-group-id

• Mapping is installed in the CEF table when

a prefix is added from the BGP table

• Marking is applied to incoming packets

based on value stored in the CEF table

3141_05_2001_c1_X

Agenda

• QoS Introduction

• Deployment Guide

• Configuring QoS in IOS

• Case Studies

• References

(23)

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“

In theory, theory and practice

are the same. In practice, they

never are.

”

Quote Slide

Jesse Liberty

(24)

3141_05_2001_c1_X

Service Definition

• Service Provider offers three classes

of service:

Premium:

Max BW, low latency, no loss

Business:

Min BW, low loss

Best Effort: No guarantees

© 2001, Cisco Systems, Inc. All rights reserved. 484848 IPS-231 3141_05_2001_c1_X CE Outbound LLQ WRED FR TS FRF.12 cRTP PE Inbound Police Marking 7200 Series 7500 Series 7600 Series 10000 Series 2500 Series 3640 Series 7200 Series CE PE FR CE PE

(25)

CE-to-PE QoS for Frame Relay Access

CE Outbound

• Per-PVC LLQ for min

BW guarantees and

congestion management

• WRED to implement

dropping policy and

increase link utilization

• Limit bursting above CIR

• Fragmentation and cRTP

on slow links

3141_05_2001_c1_X

!

class-map match-all PREMIUM match ip access-group 101 class-map match-all BUSINESS

match ip access-group 102 ! policy-map OUT-POLICY class PREMIUM priority 128 set ip dscp ef class BUSINESS bandwidth 256 set ip dscp af31 random-detect dscp-based class class-default set ip dscp 0 random-detect dscp-based ! CE Outbound LLQ WRED FR TS FRF.12 cRTP FR CE PE

CE-to-PE QoS for Frame Relay Access

CE Outbound (Cont.)

(26)

3141_05_2001_c1_X

!

interface Serial0/0.1 point-to-point ip address 10.10.1.2 255.255.255.0 frame-relay interface-dlci 16

class FR-class !

map-class frame-relay FR-class

frame-relay cir 512000 frame-relay bc 512 frame-relay mincir 512000 service-policy output OUT -POLICY frame-relay fragment 512

frame-relay ip rtp header -compression

! CE Outbound LLQ WRED FR TS FRF.12 cRTP FR CE PE

CE-to-PE QoS for Frame Relay Access

CE Outbound (Cont.)

Core

CE-to-PE QoS for Frame Relay Access

PE Inbound

• Mark and police traffic

according to contract

• P routers will service

traffic based on marking

• If provider uses MPLS,

define mapping between

DSCP/IP Prec and EXP

field

(27)

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!

class-map match-all PREMIUM match ip dscp ef

class-map match-all BUSINESS match ip dscp af31 af32 af33 !

policy-map IN-POLICY class PREMIUM

police 128000 4000 4000 conform -action transmit exceed-action drop class BUSINESS

police 256000 8000 8000 conform -action transmit

exceed-action set -dscp -transmit af32 violate -action set-dscp-transmit af33 class class-default set ip dscp 0 ! PE Inbound Police Marking FR CE PE

Core

IP

CE-to-PE QoS for Frame Relay Access

PE Inbound (Cont.)

3141_05_2001_c1_X

!

policy-map IN-POLICY class PREMIUM

police 128000 4000 4000

conform -action set-mpls-exp -transmit 5 exceed-action drop

class BUSINESS

police 256000 8000 8000

conform -action set-mpls-exp -transmit 4 exceed-action set-mpls-exp -transmit 3 class class-default set ip dscp 0 ! PE Inbound Police Marking FR CE PE

Core

MPLS

CE-to-PE QoS for Frame Relay Access

PE Inbound (Cont.)

(28)

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!

class FR-class !

map-class frame-relay FR-class frame-relay cir 512000 frame-relay bc 512 frame-relay mincir 512000

service-policy input IN-POLICY

frame-relay fragment 512 ! PE Inbound Police Marking FR CE PE

Core

CE-to-PE QoS for Frame Relay Access

PE Inbound (Cont.)

© 2001, Cisco Systems, Inc. All rights reserved. 565656 IPS-231 3141_05_2001_c1_X 7200 Series 7500 Series 7600 Series 10000 Series PE PE PE PE P P P P PE Outbound LLQ WRED

Core

PE

PE-to-P QoS

(29)

Core

PE-to-P QoS

PE Outbound

• Traffic classified

based on inbound

marking

• LLQ for min BW

guarantees and

congestion

management

• WRED to implement

dropping policy and

increase link

utilization

Core

PE-to-P QoS

PE Outbound Lower Layer Specifics

• For switched ethernet,

mark 802.1p/q COS

field and provision

QoS on switch

• For MPLS,

classification of

packets on EXP bits

• For ATM, PVC bundles

(30)

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!

policy-map OUT -POLICY class PREMIUM priority 16384 class BUSINESS bandwidth 65536 random-detect dscp-based class class-default random-detect dscp-based ! interface POS1/0 ip address 10.150.1.1 255.255.255.0

service-policy output OUT -POLICY

! PE Outbound LLQ WRED PE PE PE PE P P P P

Core

IP

PE-to-P QoS

PE Outbound (POS)

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!

policy-map OUT -POLICY class PREMIUM priority 16384 set cos 5 class BUSINESS bandwidth 65536 set cos 3 random-detect dscp-based class class-default set cos 0

random -detect dscp -based

!

interface FastEthernet1/0

ip address 10.150.1.1 255.255.255.0

Core

IP

PE-to-P QoS

PE Outbound (Ethernet)

(31)

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!

class-map match-all PREMIUM match mpls experimental 5 !

class-map match-all BUSINESS match mpls experimental 3 4 !

policy-map OUT -POLICY class PREMIUM priority 16384 class BUSINESS bandwidth 65536 random-detect class class-default random-detect ! interface POS1/0 ip address 10.150.1.1 255.255.255.0

Core

MPLS

PE-to-P QoS

PE Outbound (MPLS)

Core

IP !

policy-map OUT -POLICY class class-default random-detect ! interface ATM1/0/0 no ip address bundle BOSTON protocol ip 10.23.45.2 broadcast encapsulation aal5snap pvc-bundle 0/35

vbr-nrt 5000 3000 500

precedence 4-7

pvc-bundle 0/34

vbr-nrt 4000 3000 500

precedence 2-3

pvc-bundle 0/33

service-policy output OUT -POLICY precedence other

!

PE-to-P QoS

(32)

Core

P P

P-to-P QoS

Core

P-to-P QoS

P Outbound

• LLQ for min BW

guarantees and

congestion management

• WRED to implement

dropping policy and

increase link utilization

• Same CLI on GSR for IP

and MPLS packets (MQC

in the future)

• No need for

(33)

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interface POS2/0

ip add 10.64.12.1 255.255.255.252

tx-cos OUT -POLICY

!

cos-queue -group OUT -POLICY precedence 0 queue 0 precedence 3 queue 1

precedence 5 queue low -latency precedence 0 random-detect-label 0 precedence 3 random-detect-label 1 random -detect -label 0 3000 5000 1 random -detect -label 1 6000 8000 1 queue 0 5

queue 1 10

queue low-latency strict-priority ! P Outbound LLQ (MDRR) WRED PE PE PE PE P P P P

Core

P-to-P QoS

P Outbound (Cont.)

Core

P P

P-to-PE QoS

(34)

Core

P-to-PE QoS

P Outbound

• Configuration similar

to QoS configuration

on P-to-P

• LLQ for min BW

guarantees and

congestion

management

• WRED to implement

dropping policy and

increase link utilization

• No need for

inbound policy

Core

P-to-PE QoS

P Outbound Lower Layer Specifics

• For switched ethernet,

mark 802.1p/q COS

field and provision

QoS on switch

• For MPLS, Upstream

PE should advertise

explicit NULL If PHP

exposes IP packet

• For ATM, PVC bundles

(35)

© 2001, Cisco Systems, Inc. All rights reserved. 696969 IPS-231 3141_05_2001_c1_X PE Outbound LLQ WRED FR TS FRF.12 cRTP 7200 Series 7500 Series 7600 Series 10000 Series 2500 Series 3640 Series 7200 Series CE PE

Core

FR CE PE

PE-to-CE QoS for Frame Relay Access

Core

FR CE PE

PE-to-CE QoS for Frame Relay Access

PE Outbound

• Per-PVC LLQ for min

BW guarantees and

congestion

management

• WRED to implement

dropping policy and

increase link utilization

• Shape traffic due to

PE-to-CE speed mismatch

• Fragmentation and

(36)

3141_05_2001_c1_X

For MPLS:

PE-to-CE QoS for Frame Relay Access

PE Outbound Lower Layer Specifics

Core

FR

CE PE

• Who specifies outbound

QoS policy (customer or

provider)?

• In most cases, provider

will prefer to use its

QoS policy

• Outbound IP packets

will have to be

classified based on

previous EXP value

(Future feature)

PE Outbound LLQ WRED FR TS FRF. 12 cRTP

Core

IP FR CE PE PE Outbound LLQ WRED FR TS FRF. 12 cRTP !

!

policy-map OUT -POLICY class PREMIUM priority 128 class BUSINESS bandwidth 256 random-detect dscp-based class class-default random-detect dscp-based !

QoS for Frame Relay CE-PE

PE Outbound (Cont.)

(37)

Core

FR CE PE PE Outbound LLQ WRED FR TS FRF. 12 cRTP !

class FR-class !

map-class frame-relay FR-class

frame-relay cir 512000 frame-relay bc 5120 frame-relay mincir 512000 service-policy output OUT -POLICY frame-relay fragment 512

frame-relay ip rtp header -compresssion

!

QoS for Frame Relay CE-PE

PE Outbound (Cont.)

QoS High Level View

• Marking, policing and

shaping should be

done at the edges

of the network

• Queuing and dropping

done in the core based

on packet marking

• One class for low

latency traffic

• A small number of

additional classes to

implement SLAs

(38)

MPLS

(ATM / POS)

Case Study 2: Service Provider ABC

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Application Delay Jitter Packet Loss

Premium

Silver

Bronze

Voice Low Low Low

Business Critical Non-critical Undefined Undefined Undefined Undefined Low Undefined Gold Interactive Low Undefined Low

Four Classes of Service Offered to Customers

Service Provider ABC

Service Definition

(39)

© 2001, Cisco Systems, Inc. All rights reserved. 777777 IPS-231 3141_05_2001_c1_X CE-to-PE Outbound LLQ WRED FR TS FRF. 12 cRTP CE-to-PE Inbound Marking (EXP) PE-to-CE Outbound LLQ WRED FR TS FRF. 12 cRTP CE PE P POP

MPLS

(ATM / POS)

PE-to-P Outbound LLQ (accounting)

Service Provider ABC

QoS Deployment

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Service Provider ABC

QoS Deployment (Cont.)

• QoS-enabled IP VPN services

implemented with MPLS VPNs

• QoS policies initially applied on

access links only

• QoS will be deployed in the core

in the near future

(40)

IP

(POS)

Case Study 3: Service Provider XYZ

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Delay Jitter Packet Loss

Priority Low Low Low

Best Effort Undefined Undefined Undefined

Two Classes of Service Offered to Customers

Application

VoIP

Data

Service Provider XYZ

Service Definition

(41)

© 2001, Cisco Systems, Inc. All rights reserved. 818181 IPS-231 3141_05_2001_c1_X CE-to-PE Inbound Marking QPPB Marking (community) PE-to-P Outbound LLQ (MDRR) WRED P-to-P Outbound LLQ (MDRR) WRED P-to-PE Outbound LLQ (MDRR) WRED CE (Non-VoIP) CE (Interconnect) PE PE PE P P CE (Retail VoIP) IP (POS)

Service Provider XYZ

QoS Deployment

3141_05_2001_c1_X

Service Provider XYZ

QoS Deployment (Cont.)

• QoS policies deployed in backbone to

decommission redundant VoIP backbone

• VoIP and data traffic marked at the edge

to retail VoIP customers and Internet

interconnect points using QPPB

• All traffic from non-VoIP customers

remarked to best effort

• Currently evaluating introduction of

additional classes

(42)

Agenda

• QoS Introduction

• Deployment Guide

• Configuring QoS in IOS

• Case Studies

• References

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References

• Networkers Session PS-560 (QoS Essentials)

• Networkers Session IPS-130 (Introduction to QoS)

• Networkers Session IPS-330 (Troubleshooting QoS Technologies)

• Networkers Session IPS-430 (Advanced Concepts and

Developments in QoS)

• QoS Configuration Guide

http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/ 121cgcr/qos_c/index.htm

• QoS Command Reference

http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/ 121cgcr/qos_r/index.htm

• Quality of Service for the Cisco 7200/7500

http://wwwin.cisco.com/cmc/cc/pd/iosw/ioft/ioqo/tech/qos72_wp.htm

• MPLS Class of Service Enhancements

http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/ 121newft/121t/121t5/mct1 214t.htm

(43)

85

IPS-231

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Deploying QoS in Service

Provider Networks

Session IPS-231

86

IPS-231

3141_05_2001_c1_X 86

Please Complete Your

Evaluation Form

(44)

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IPS-231 3141_05_2001_c1_X