MPLS cisco QOS VPN full 05 mpls qos

Service Provider QoS
Providing e2e Guarantees
Vijay Krishnamoorthy

Cisco IOS Technologies Division
April 2001
© 2001, Cisco Systems, Inc.

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Agenda

• What is QoS?
• QoS Models
• Differentiated Services - DiffServ
• DiffServ in MPLS Networks
• MPLS Traffic Engineering
• DiffServ-Aware Traffic Engineering (DS-TE)
• DS-TE Solutions
• QoS Management
• Summary
© 2001, Cisco Systems, Inc.

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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
© 2001, Cisco Systems, Inc.

”
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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!

© 2001, Cisco Systems, Inc.

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Service Provider Revenue/Margin
Potential
Today’s Basic Internet Access
Basic Internet Access @ 768 kpbs…………

Monthly Revenue/Margin
$500/$50

Managed Internet Access
Access prioritization by user, group………... $75/$60
Priority access during times of congestion… $75/$60
Usage reporting………………………………. $75/$60
Business Applications (ASP)
Priority to each customer’s requirements….. $100/$90
Streaming Services
Blocking delivery of undesirable services…. $50/$40
VPN Services
Low cost, software based …………………… $150/$100
TOTAL MARGIN POTENTIAL:
$460/customer = +820%
Source: Session M16C, SuperNet 2001
© 2001, Cisco Systems, Inc.

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But…but… Bandwidth…...

“

“Money

and sex, storage and bandwidth: only too
much is ever enough”
•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”
© 2001, Cisco Systems, Inc.

”

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So, What Will Fill Up The Pipe?

Source: Internet2 QBone WG
© 2001, Cisco Systems, Inc.

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QoS Models

©©2001,
2001,Cisco
CiscoSystems,
Systems,Inc.
Inc.

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The IP QoS Pendulum
Time
No state

Aggregated
state

Best Effort

DiffServ

Per-flow state

IntServ / RSVP

1. The original IP service

2. First efforts at IP QoS

3. Seeking simplicity and scale
4. Bandwidth Optimization & e2e SLAs
((IntServ+DiffServ+ Traffic
Engineering))
© 2001, Cisco Systems, Inc.

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MissionCritical
Critical
Mission
Services
Services

POLICY-BASED
POLICY-BASEDNETWORKING
NETWORKING

VoIP
VoIP
IntServ
IntServ

Multimedia
Multimedia
Video Conference,

VPNs
VPNs

MPLS
MPLS

Hybrid
Hybrid

Video Conference,
Collaborative Computing
Collaborative Computing

DiffServ
DiffServ

SignalingTechniques
Techniques(RSVP,
(RSVP,DSCP*,
DSCP*,ATM
ATM(UNI/NNI))
(UNI/NNI))
Signaling
Classification&&Marking
MarkingTechniques
Techniques(DSCP,

(DSCP,MPLS
MPLSEXP,
EXP,NBAR,
NBAR,etc.)
etc.)
Classification
CongestionAvoidance
AvoidanceTechniques
Techniques(WRED)
(WRED)
Congestion
TrafficConditioners
Conditioners(Policing,
(Policing,Shaping)
Shaping)
Traffic
CongestionManagement
ManagementTechniques
Techniques(WFQ,
(WFQ,CBWFQ,
CBWFQ,LLQ)
LLQ)
Congestion

PROVISIONING
PROVISIONING&&MONITORING
MONITORING

The Cisco QoS Framework

LinkEfficiency
EfficiencyMechanisms
Mechanisms(Compression,
(Compression,Fragmentation)
Fragmentation)
Link
Frame
Frame
Relay
Relay
© 2001, Cisco Systems, Inc.

PPP
PPP
HDLC
HDLC

SDLC
SDLC

ATM, POS
ATM, POS

FE,Gig.E
FE,Gig.E
10GE
10GE

Wireless
BroadBand

Wireless
BroadBand
Fixed,Mobile Cable,xDSL
Fixed,Mobile Cable,xDSL
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Differentiated Services
Architecture - DiffServ

©©2001,
2001,Cisco
CiscoSystems,
Systems,Inc.
Inc.

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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”
• Two-Ingredient Recipe:
Condition the Traffic at the Edges
Invoke the PHBs in the Core

• Use PHBs to Construct Services such as Virtual
Leased Line!

© 2001, Cisco Systems, Inc.

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The Hook for IPv4 Classification
Referred to as Packet Classification or Coloring

Layer 3
IPV4
Version ToS
ToS
Len
Length 11 Byte
Byte

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

ID

offset TTL Proto FCS IP-SA IP-DA Data

Layer 3 Mechanisms Provide End-to-End Classification

© 2001, Cisco Systems, Inc.

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IPv4 ToS vs. DS-Field

© 2001, Cisco Systems, Inc.

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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)

© 2001, Cisco Systems, Inc.

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AF PHB Group Definition
AF Class 1: 001dd0
AF Class 2: 010dd0
AF Class 3: 011dd0

AF Class 4: 100dd0

dd = drop preference
Eg. AF12 = Class 1, Drop 2, thus “001100”

• 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.
© 2001, Cisco Systems, Inc.

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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
•Shaper: delay some packets for them to be compliant with the profile
© 2001, Cisco Systems, Inc.

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The DiffServ Architecture

(RFC-2475)

© 2001, Cisco Systems, Inc.

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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...

© 2001, Cisco Systems, Inc.

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An Application Note

©©2001,
2001,Cisco
CiscoSystems,
Systems,Inc.
Inc.

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Source Predictability

• TCP will keep at most a certain amount of
traffic in flight
We say it is “elastic”—rate is proportional to
latency

• Voice will send only and exactly as fast as
the coding algorithm permits (Also Video to
an extent)
We say it is “inelastic”

© 2001, Cisco Systems, Inc.

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TCP Flow Statistics

• >90% of sessions have ten packets each
way or less
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

© 2001, Cisco Systems, Inc.

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Behavior of a High-Throughput /
Bulk-Transfer TCP Session
45
40
Congestion Avoidance Phase
Linear Growth

35
30
25
20
15
10

Slow Start
Exponential Growth

5
0

0

© 2001, Cisco Systems, Inc.

10

20

30

40

50

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VoIP Delay Budget
Cumulative Transmission Path Delay
Satellite Quality
Fax Relay, Broadcast

High Quality
0

100

200

300

400

500

600

700

800

Time (msec)
Delay Target (max)

ITU’s G.114 Recommendation = 0–150 msec 1-Way Delay

© 2001, Cisco Systems, Inc.

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Application QoS Requirements
Voice

FTP

ERP and
Mission-Critical

Bandwidth

Low to
Moderate

Moderate
to High

Low

Random Drop Sensitive

Low

High

Moderate
To High

Delay Sensitive

High

Low

Low to
Moderate

Jitter Sensitive

High

Low

Moderate

© 2001, Cisco Systems, Inc.

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