MPLS cisco QOS VPN full 05 mpls qos

DiffServ Scalability via Scheduling/Dropping PHB based on DSCP Diff-Serv: Aggregated Processing in Core Scheduling/Dropping PHB based on DSCP Diff-Serv: Aggregation on Edge Many flows

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Service Provider QoS Providing e2e Guarantees

Vijay Krishnamoorthy Cisco IOS Technologies Division

April 2001

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What is Quality of Service?

ARM Your Network!

“

”

The Pragmatic Answer: QoS is Advanced Resource Management

The Technical Answer: The Resources!!

Set of techniques to manage:

• Delay

• Delay Variation (Jitter)

• Bandwidth

• Packet Loss

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The Value Proposition!

• Offer Any to Any Differentiated Services for Profitability:

Premium-Class Service – (E.g.: VoIP, Multicast Stock Quotes, etc.)

Business-Class Service – (E.g.: SAP,Oracle,Citrix, etc.) Best-Effort Service – (E.g.: Database Replication,

Backups, etc.)

• Icing on the profitability cake  Point-to-Point QoS Guarantees:

P2P guarantees for Voice over IP trunks.

P2P guarantees for highly critical data traffic.

• Revenue in addition to Basic MPLS VPN & Internet Service!

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Today’s Basic Internet Access

Basic Internet Access @ 768 kpbs…………

Managed Internet Access

Access prioritization by user, group………

Priority access during times of congestion…

Usage reporting……….

Business Applications (ASP)

Priority to each customer’s requirements…

Service Provider Revenue/Margin

Potential

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•Arno Penzias - Former Head of Bell Labs, and Nobel prizewinner

“ The worldwide services market is about $1 trillion

US By 2005 it will be around $5-7 trillion Look for

growth in new services ”

•Vinod Khosola - Kleiner Perkins Ventures

”According to CIMI Corporation, by 2010, 67% of transactions will be on value networks, not the

Internet”

“

”

But…but… Bandwidth…

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So, What Will Fill Up The Pipe?

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The IP QoS Pendulum

DiffServ

1 The original IP service

2 First efforts at IP QoS

3 Seeking simplicity and scale

Time

4 Bandwidth Optimization & e2e SLAs

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Video Conference, Collaborative Computing

DiffServ IntServ

Signaling Techniques (RSVP, DSCP*, ATM (UNI/NNI))

Link Efficiency Mechanisms (Compression, Fragmentation)

Congestion Avoidance Techniques (WRED)

Congestion Management Techniques (WFQ, CBWFQ, LLQ) Classification & Marking Techniques (DSCP, MPLS EXP, NBAR, etc.)

Frame Relay

Frame Relay HDLC PPP

PPP HDLC SDLC ATM, POS FE,Gig.E 10GE

FE,Gig.E 10GE Fixed,Mobile Wireless

Wireless Fixed,Mobile Cable,xDSL BroadBand

BroadBand Cable,xDSL

Traffic Conditioners (Policing, Shaping)

The Cisco QoS Framework

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Differentiated Services Architecture - DiffServ

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Differentiated Services The IETF DiffServ Model

• Use 6 bits in IP header to sort traffic into

“Behavior Aggregates”…AKA Classes!

• Defines a number of “Per Hop Behaviors - PHBs”

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1 Byte Len Len

Standard IPV4: Bits 0-2 Called IP Precedence (Three MSB) (DiffServ Uses Six ToS bits…: Bits 0-5, with Two Reserved)

Layer 3

IPV4

ID offset TTL offset TTL Proto Proto FCS FCS IP-SA IP-SA IP-DA IP-DA Data Data

Referred to as Packet Classification or Coloring

Layer 3 Mechanisms Provide End-to-End Classification

The Hook for IPv4 Classification

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IPv4 ToS vs DS-Field

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Defined PHBs

• Expedited Forwarding (EF): RFC2598

dedicated low delay queue Comparable to Guaranteed B/W in IntServ

• Assured Forwarding (AF): RFC2597

4 queues × 3 drop preferences Comparable to Controlled Load in IntServ

• Class Selector: Compat with IP Prec

• Default (best effort)

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AF PHB Group Definition

• 4 independently-forwarded AF classes

• Within each AF class, 3 levels of drop priority! This is very

useful to protect conforming to a purchased, guarantee rate,

while increasing chances of packets exceeding contracted rate

being dropped if congestion is experienced in the core.

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The DiffServ Traffic Conditioner

•Classifier : selects a packet in a traffic stream based on the content of some portion of the packet header

•Meter: checks compliance to traffic parameters (e.g., Token Bucket) and passes

result to marker and shaper/dropper to trigger particular action for in/out-of-profile packets

•Marker: Writes/rewrites the DSCP value

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The DiffServ Architecture

(RFC-2475)

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Cisco IOS DiffServ

• Cisco IOS 12.1(5)T+ & 12.2+ are fully compliant with all the

Core DiffServ RFCs (RFCs: 2474,2475,2597,2598)

• Compliant Platforms*:

C36xx, C72xx, C75xx - Now More Platforms in the Near Future

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• Voice will send only and exactly as fast as

the coding algorithm permits (Also Video to

an extent)

We say it is “inelastic”

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Transaction mode (mail, small web page)

• >80% of all TCP traffic results from <10%

of the sessions, in high rate bursts

It is these that we worry about managing

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Behavior of a High-Throughput /

Bulk-Transfer TCP Session

0 5 10 15 20 25 30 35 40 45

Slow Start Exponential Growth

Congestion Avoidance Phase

Linear Growth

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VoIP Delay Budget

Cumulative Transmission Path Delay

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Application QoS Requirements

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DiffServ Scalability via

Scheduling/Dropping (PHB) based on DSCP

Diff-Serv:

Aggregated Processing in Core

Scheduling/Dropping (PHB) based on DSCP

Diff-Serv:

Aggregation on Edge Many flows associated with

a Class (marked with DSCP)

Diff-Serv:

Aggregation on Edge Many flows associated with

a Class (marked with DSCP)

DiffServ scalability comes from:

- aggregation of traffic on Edge

- processing of Aggregate only in Core

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MPLS Scalability via Aggregation

1000’s

of flows

MPLS:

Forwarding based on label

MPLS:

Forwarding based on label

Class (marked with label)

MPLS scalability comes from:

- processing of Aggregate only in Core

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MPLS & DiffServ - The Perfect

MPLS:

Switching based on Label

DS:

Scheduling/Dropping based on DSCP

DS:

Scheduling/Dropping based on DSCP

DS: flows associated with Class, mapped

to DSCP

DS: flows associated with Class, mapped

to DSCP

Because of same scalability goals, both models do:

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• DSCP field is not directly visible to MPLS Label Switch Routers

(they forward based on MPLS Header)

• Information on DiffServ must be made visible to LSR in MPLS

Header (using EXP field / 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 |

DSCP

IPv4 Packet MPLS Header

Non-MPLS Diff-Serv Domain

MPLS Diff-Serv Domain

DSCP

MPLS - So What’s New?

The Shim Header!!

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– 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 {{ Planned, once an RFC }}

“Queue” inferred exclusively from Label

“Drop priority” inferred from EXP field

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• E-LSPs can be established by various label binding protocols

(LDP or RSVP)…no new Signalling Needed.

• Example above illustrates support of EF and AF1 on a single

E-LSP (Note: This is the plain old LSP established for MPLS Switching)

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

• Queue & Drop Precedence is selected based on EXP

E-LSP

LSR

EF AF1

The E-LSP Story

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• L-LSPs can be established by various label binding

protocols (LDP or RSVP)…EXTENSIONS REQUIRED!

separate L-LSPs

– EF and AF1 packets travel on separate LSPs and are enqueued in different queues (different label values) – Queue selected based on Label, Drop Precedence Selected

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• Operate exclusively on EXP bits

• Leave the IP ToS Byte Untouched

• QoS is QoS!

– Some New Stuff, But Same Goals!

– Service the Applications!!

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The QoS is In the Details!

• So, What’s Changed?:

Can Classify based on the EXP bits (MQC/CAR)

Can Mark the EXP bits (MQC/Policer/CAR) WRED & WFQ & MDRR act on EXP bits (instead of Precedence/DSCP)

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A Note on CoS Translation…

(Preservation of Classification e2e)

• Developed as flexible translation:

• CoS = {IP Prec., DSCP, EXP, ATM CLP, F.Relay DE-Bit, 802.1Q/p}

• CoS translation = Translation from Any (Except ATM CLP) to Any

• Extensions to the “Modular QoS CLI”:

1) Extended “matches” for “class-maps”:

match fr-de match cos <0-7>

match ip precedence n match ip dscp n

match mpls exp <0-7>

2) Extended “sets” for “policy-maps”:

set atm-clp set fr-de set cos <0-7>

set ip precedence n set ip dscp n

set mpls exp n

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class inputc set qos-group q Incoming interface> service-policy input inputp

LSP

LSR

MPLS

Incoming IP packets with Prec=p

to be transmitted with EXP=e

class-map outputc

match qos-group q policy-map outputp

class outputc set mpls exp e Outgoing interface> service policy output outputp

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The “Fish” Problem R8

R1

R5 R2

R3

R4

R7 R6

•IP Uses Shortest Path Destination-Based Routing

•Shortest Path May Not Be the only path

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R4

R7 R6

Labels, Like VCIs (ATM) Can Be Used to Establish Virtual Circuits

Normal Route R1->R2->R3->R4->R5 Tunnel: R1->R2->R6->R7->R4

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Setup: Path (R1->R2->R6->R7->R4->R9) Tunnel ID 5, Path ID 1

Reply: Communicates Labels and Label Operations

Pop

32

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MPLS TE & QoS – The Relationship

• MPLS TE designed as tool to improve backbone efficiency independently of core QoS techniques:

MPLS TE compute routes for aggregates across all PHBs.

A Single Chunk of Bandwidth requested for the Tunnel

MPLS TE performs admission control over a global b/w pool.

Un-aware of bandwidth allocated to each Class / PHB

• MPLS TE and MPLS DiffServ:

Can run simultaneously in a network.

Can provide their own individual benefits

TE distributes aggregate load DiffServ provides differentiation) Are unaware of each other

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DiffServ-Aware Traffic Engineering

44

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Delay/Load Trade-Off

Percentage Priority

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Motivation for DiffServ-Aware TE

• - Admission Control per Class over different

bandwidth pools (ie bandwidth allocated to class

queue)

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The Trouble With DiffServ (We Want it All, We Want it Now!)

simplicity and weak on guarantees

much can be deployed?

No topology-aware admission control mechanism

TRUNK that will degrade service of calls & trunks currently active?

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DiffServ-Aware TE:

Protocol Components

advertise “unreserved TE bandwidth” (at each preemption level)

Class-Types= group of DiffServ classes sharing the same bandwidth constraint (e.g AF1x and AF2x)

advertise “unreserved TE bandwidth” (at each preemption level) for each Class-Type

(*) OSPF and ISIS

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DiffServ-Aware TE:

at LSP establishment signal TE tunnel parameters (label, explicit route, affinity , preemption,…)

DS aware TE:

also signal the Class-Type perform Class-Type aware CAC

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DiffServ - Aware TE:

compute a path such that on every link :

- there is sufficient “unreserved TE bandwidth”

TE:

same CBR algorithm but satisfy bandwidth constraint over the “unreserved bandwidth for the relevant Class- Type” (instead of aggregate TE bandwidth)

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DS-TE Standardization Status

draft-ietf-mpls-diff-te-reqts-01.txt draft-ietf-mpls-diff-te-ext-00.txt draft-lefaucheur-diff-te-ospf-00.txt draft-lefaucheur-diff-te-isis-00.txt

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Aggregate TE in a Best Effort

Network

POP4

POP

POP POP

POP2

POP1

WAN area

Find route & set-up tunnel for 20 Mb/s from POP1 to POP4

Find route & set-up tunnel for 10 Mb/s from POP2 to POP4

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Aggregate TE in a DiffServ

Network

POP4

POP POP2

POP1

WAN area

Find route & set-up tunnel for 20 Mb/s (aggregate) from POP1 to POP4

Find route & set-up tunnel for 10 Mb/s (aggregate) from POP2 to POP4

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POP1

WAN area

Find route & set-up tunnel for 5 Mb/s of EF from POP1 to POP4

Find route & set-up tunnel for 15 Mb/s of BE from POP1 to POP4

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DS-TE Applications

Guaranteed Bandwidth Services

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POP1

WAN area

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MPLS Guaranteed Bandwidth

• Combining MPLS DiffServ & DS-TE to achieve

strict point-to-point QoS guarantees

• A new “sweet-spot” on the QoS Spectrum

MPLS

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• “Guaranteed QoS” is a unidirectional point-to-point

bandwidth guarantee from Site-Sx to Site-Sy: Point

Point-to-• “Site” may include a single host, a “pooling point”, etc.

CE

N1 Mb/s guarantee N2 Mb/s

guarantee

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• “Guaranteed QoS” is a unidirectional point-to-point

bandwidth guarantee from Site-Sx to Site-Sy

• “Site” may include a single host, a “pooling point”, etc.

CE

N1 Mb/s guarantee N2 Mb/s

guarantee

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Target Applications

Solution 1: Toll Bypass with Voice Network Solution 2: Toll Bypass with Voice/Data Converged Network Solution 3: Toll Bypass with VoIP Network

• Virtual Leased Lines

Solution 4: Virtual Leased Lines – Serial Links Solution 5: Virtual Leased Lines – Frame Relay Solution 6: Virtual Leased Lines – ATM

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Solution 1: Toll Bypass with Voice

Network

PE

PBX with Packet Interfac e

PBX with Packet Interface

PSTN – Traditional TDM Network

Tradition

al Telephon y

Solution

Requirements

Mapping Traffic to Tunnels

Diffserv Aware Traffic Engineering

QoS on Core Routers

PE

GB Tunnel

⇒

Class 5 legacy switches

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Solution 2: Toll Bypass with Voice/Data

Converged Network

PE

CE

PBX with Circuit Emulatio

n Interface

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Solution 3: Toll Bypass with VoIP

Solution

Requirements

Mapping Traffic to Tunnels

Diffserv Aware Traffic Engineering

QoS on Core Routers

CE

QoS on

CE Router

Service Switch

Multi-IP Phone

PE

GB Tunnel

⇒

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Voice Trunking - Summary

PE

Central Office

Central

Telephon y

Tradition

al Telephon y

Toll Bypass

PE

GB Tunnel

VoIP Gatewa y

VoIP Gateway

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Solution 4: Virtual Leased Lines –

PE DS-TE Tunnel

Serial IP

or PPP or HDLC over MPLS

Serial

Link Virtual

Leased Line (DS-TE + QoS)

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FR Networks

PE

MPLS Backbone

PE

Frame Relay

CPE Router, FRAD

Frame Relay Frame Relay DLCI

Any Transport over MPLS (AToM)

Tunnel

DS-TE Tunnel Virtual Leased Line

(DS-TE + QoS)

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ATM Networks

PE

MPLS Backbone

Any Transport over MPLS (AToM) Tunnel

DS-TE Tunnel Virtual Leased Line

(DS-TE + QoS)

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QoS Management

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Network service level verification CW2000 SMS

Complete Service Management

Qos network policy configuration

Per-device traffic class monitoring

Per-device traffic class configuration

XML

(IPM) CW2000 RWAN

(IPM)

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