Optimizing Converged
Cisco Networks (ONT)
Module 3: Introduction to IP QoS
© 2006 Cisco Systems, Inc. All rights reserved.
Lesson 3.1:
Introducing QoS
© 2006 Cisco Systems, Inc. All rights reserved.
Objectives
 Explain why converged networks require QoS.
 Identify the major quality issues with converged
networks.
 Calculate available bandwidth given multiple flows.
 Describe mechanisms designed to use bandwidth more
efficiently.
 Describe types of delay.
 Identify ways to reduce the impact of delay on quality.
 Describe packet loss and ways to prevent or reduce
packet loss in the network.
© 2006 Cisco Systems, Inc. All rights reserved.
Traditional Nonconverged Network
 Traditional data traffic characteristics:
Bursty data flow
FIFO access
Not overly time-sensitive; delays OK
Brief outages are survivable
© 2006 Cisco Systems, Inc. All rights reserved.
Converged Network Realities
 Converged network realities:
Constant small-packet voice flow competes
with bursty data flow.
Critical traffic must have priority.
Voice and video are time-sensitive.
Brief outages are not acceptable.
© 2006 Cisco Systems, Inc. All rights reserved.
Converged Network Quality Issues
 Lack of bandwidth: Multiple flows compete for a limited
amount of bandwidth.
 End-to-end delay (fixed and variable): Packets have to
traverse many network devices and links; this travel
adds up to the overall delay.
 Variation of delay (jitter): Sometimes there is a lot of
other traffic, which results in varied and increased
delay.
 Packet loss: Packets may have to be dropped when a
link is congested.
© 2006 Cisco Systems, Inc. All rights reserved.
Measuring Available Bandwidth
 The maximum available bandwidth is the bandwidth of the slowest link.
 Multiple flows are competing for the same bandwidth, resulting in much less
bandwidth being available to one single application.
 A lack in bandwidth can have performance impacts on network applications.
© 2006 Cisco Systems, Inc. All rights reserved.
Increasing Available Bandwidth




Upgrade the link (the best but also the most expensive solution).
Improve QoS with advanced queuing mechanisms to forward the important packets first.
Compress the payload of Layer 2 frames (takes time).
Compress IP packet headers.
© 2006 Cisco Systems, Inc. All rights reserved.
Using Available Bandwidth Efficiently
Voice
1
1
• LLQ
• RTP header
compression
(Highest)
Data
2
2
3
3
3
4
4
4
(High)
Data
(Medium)
Data
Voice
4
4
3
2
1
1
Data
• CBWFQ
• TCP header
compression
(Low)
 Using advanced queuing and header compression mechanisms,
the available bandwidth can be used more efficiently:
Voice: LLQ and RTP header compression
Interactive traffic: CBWFQ and TCP header compression
© 2006 Cisco Systems, Inc. All rights reserved.
Types of Delay
 Processing delay: The time it takes for a router to take the packet from an input
interface, examine the packet, and put the packet into the output queue of the
output interface.
 Queuing delay: The time a packet resides in the output queue of a router.
 Serialization delay: The time it takes to place the “bits on the wire.”
 Propagation delay: The time it takes for the packet to cross the link from one end to
the other.
© 2006 Cisco Systems, Inc. All rights reserved.
The Impact of Delay and Jitter on Quality
 End-to-end delay: The sum of all propagation, processing,
serialization, and queuing delays in the path
 Jitter: The variation in the delay.
 In best-effort networks, propagation and serialization delays are fixed,
while processing and queuing delays are unpredictable.
© 2006 Cisco Systems, Inc. All rights reserved.
Ways to Reduce Delay





Upgrade the link (the best solution but also the most expensive).
Forward the important packets first.
Enable reprioritization of important packets.
Compress the payload of Layer 2 frames (takes time).
Compress IP packet headers.
© 2006 Cisco Systems, Inc. All rights reserved.
Reducing Delay in a Network
 Customer routers perform:
TCP/RTP header compression
LLQ
Prioritization
 ISP routers perform:
Reprioritization according to the QoS policy
© 2006 Cisco Systems, Inc. All rights reserved.
The Impacts of Packet Loss
 Telephone call: “I cannot understand you. Your voice is breaking up.”
 Teleconferencing: “The picture is very jerky. Voice is not synchronized.”
 Publishing company: “This file is corrupted.”
 Call center: “Please hold while my screen refreshes.”
© 2006 Cisco Systems, Inc. All rights reserved.
Types of Packet Drops
 Tail drops occur when the output queue is full. Tail drops are common
and happen when a link is congested.
 Other types of drops, usually resulting from router congestion, include
input drop, ignore, overrun, and frame errors. These errors can often
be solved with hardware upgrades.
© 2006 Cisco Systems, Inc. All rights reserved.
Ways to Prevent Packet Loss
 Upgrade the link (the best solution but also the most expensive).
 Guarantee enough bandwidth for sensitive packets.
 Prevent congestion by randomly dropping less important packets
before congestion occurs.
© 2006 Cisco Systems, Inc. All rights reserved.
Traffic Rate
Policing
Traffic
Traffic
Traffic Policing and Traffic Shaping
Time
Traffic Rate
Shaping
Time
© 2006 Cisco Systems, Inc. All rights reserved.
Traffic
Traffic
Time
Traffic Rate
Traffic Rate
Time
Reducing Packet Loss in a Network
 Problem: Interface congestion causes TCP and voice packet
drops, resulting in slowing FTP traffic and jerky speech quality.
 Conclusion: Congestion avoidance and queuing can help.
 Solution: Use WRED and LLQ.
© 2006 Cisco Systems, Inc. All rights reserved.
Summary
 Converged networks carry different types of traffic over
a shared infrastructure. This creates the need to
differentiate traffic and give priority to time-sensitive
traffic.
 Various mechanisms exist that help to maximize the
use of the available bandwidth, including queuing
techniques and compression mechanisms.
 All networks experience delay. Delay can effect time
sensitive traffic such as voice and video.
 Without proper provisioning and management,
networks can experience packet loss. Packet loss is
especially important with voice and video, as no
resending of lost packets can occur.
© 2006 Cisco Systems, Inc. All rights reserved.
Resources
 Quality of Service Networking
http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/qos.ht
m
 QoS Congestion Avoidance
http://www.cisco.com/en/US/tech/tk543/tk760/tsd_technology_s
upport_protocol_home.html
 QoS Congestion Management (queuing)
http://www.cisco.com/en/US/tech/tk543/tk544/tsd_technology_s
upport_protocol_home.html
© 2006 Cisco Systems, Inc. All rights reserved.
Optimizing Converged
Cisco Networks (ONT)
Module 3: Introduction to IP QoS
© 2006 Cisco Systems, Inc. All rights reserved.
Lesson 3.2:
Implementing Cisco
IOS QoS
© 2006 Cisco Systems, Inc. All rights reserved.
Objectives
 Describe the need for QoS as it relates to various types
of network traffic.
 Identify QoS mechanisms.
 Describe the steps used to implement QoS.
© 2006 Cisco Systems, Inc. All rights reserved.
What Is Quality of Service?
Two Perspectives
 The user perspective
Users perceive that their applications are
performing properly
Voice, video, and data
 The network manager perspective
Need to manage bandwidth allocations
to deliver the desired application
performance
Control delay, jitter, and
packet loss
© 2006 Cisco Systems, Inc. All rights reserved.
Different Types of Traffic Have Different
Needs
 Real-time applications especially
sensitive to QoS
Application
Examples
Delay
Jitter
Packet
Loss
Interactive Voice
and Video
Y
Y
Y
Streaming Video
N
Y
Y
Transactional/
Interactive
Y
N
N
Bulk Data
Email
File Transfer
N
N
N
Interactive voice
Videoconferencing
 Causes of degraded performance
Congestion losses
Sensitivity to
QoS Metrics
Variable queuing delays
 The QoS challenge
Manage bandwidth allocations to
deliver the desired application
performance
Control delay, jitter, and packet
loss
© 2006 Cisco Systems, Inc. All rights reserved.
Need to manage
bandwidth allocations
Cisco IOS QoS Tools
 Congestion management:
PQ
CQ
WFQ
CBWFQ
 Queue management
WRED
 Link efficiency
Link fragmentation and interleave
RTP and CRTP
 Traffic shaping and traffic policing
© 2006 Cisco Systems, Inc. All rights reserved.
QoS Toolbox
Priority Queuing
PQ puts data into four levels of queues: high, medium,
normal, and low.
© 2006 Cisco Systems, Inc. All rights reserved.
Custom Queuing
CQ handles traffic by assigning a specified amount of queue space to each class of
packet and then servicing up to 17 queues in a round-robin fashion.
© 2006 Cisco Systems, Inc. All rights reserved.
Weighted Fair Queuing
•WFQ makes the transfer rates and interarrival periods of active high-volume conversations much
more predictable.
© 2006 Cisco Systems, Inc. All rights reserved.
Weighted Random Early Detection
•WRED provides a method that stochastically discards packets if congestion begins to increase.
© 2006 Cisco Systems, Inc. All rights reserved.
© 2006 Cisco Systems, Inc. All rights reserved.
Implementing QoS
Step 1: Identify types of traffic and
their requirements.
Step 2: Divide traffic into classes.
Step 3: Define QoS policies for
each class.
© 2006 Cisco Systems, Inc. All rights reserved.
Step 1: Identify Types of Traffic and Their
Requirements
 Network audit: Identify traffic on the network.
 Business audit: Determine how important each type of
traffic is for business.
 Service levels required: Determine required response
time.
© 2006 Cisco Systems, Inc. All rights reserved.
Step 2: Define Traffic Classes
Scavenger
Class
© 2006 Cisco Systems, Inc. All rights reserved.
Less than
Best Effort
Step 3: Define QoS Policy
 A QoS policy is a
network-wide definition of
the specific levels of QoS
that are assigned to
different classes of
network traffic.
© 2006 Cisco Systems, Inc. All rights reserved.
Quality of Service Operations
How Do QoS Tools Work?
Classification
and Marking
© 2006 Cisco Systems, Inc. All rights reserved.
Queuing and
(Selective) Dropping
Post-Queuing
Operations
Self Check
1. What types of applications are particularly sensitive to
QoS issues?
2. What is WFQ? How is it different than FIFO?
3. What are the 3 basic steps involved in implementing
QoS?
4. What is Scavenger Class?
© 2006 Cisco Systems, Inc. All rights reserved.
Summary
 QoS is important to both the end user and the network
administrator. End users experience lack of QoS as
poor voice quality, dropped calls or outages.
 Network traffic differs in its ability to handle delay, jitter
and packet loss. Traffic sensitive to these issues
requires priority treatment. QoS measures can provide
priority to sensitive traffic, while still providing services
to more resilient traffic.
 Implementing QoS involves 3 basic steps: identify the
types of traffic on your network, divide the traffic into
classes, and define a QoS policy for each traffic class.
© 2006 Cisco Systems, Inc. All rights reserved.
Resources
 QoS Best Practices At-A-Glance
http://www.cisco.com/application/pdf/en/us/guest/tech/tk759/c14
82/cdccont_0900aecd80295aa1.pdf
 QoS Tools At-A-Glance
http://www.cisco.com/application/pdf/en/us/guest/tech/tk759/c14
82/cdccont_0900aecd80295abf.pdf
© 2006 Cisco Systems, Inc. All rights reserved.
Optimizing Converged
Cisco Networks (ONT)
Module 3: Introduction to IP QoS
© 2006 Cisco Systems, Inc. All rights reserved.
Lesson 3.3:
Selecting an
Appropriate QoS
Policy Model
© 2006 Cisco Systems, Inc. All rights reserved.
Objectives
 Describe 3 QoS models: best effort, IntServ and
Diffserv.
 Identify the strengths and weaknesses of each of the 3
QoS models.
 Describe the purpose and functionality of RSVP.
© 2006 Cisco Systems, Inc. All rights reserved.
Three QoS Models
Model
Characteristics
Best effort
No QoS is applied to packets. If it is not
important when or how packets arrive, the besteffort model is appropriate.
Integrated
Services
Applications signal to the network that the
applications require certain QoS parameters.
(IntServ)
Differentiated
Services
The network recognizes classes that require
QoS.
(DiffServ)
© 2006 Cisco Systems, Inc. All rights reserved.
Best-Effort Model
 Internet was initially based on a best-effort packet
delivery service.
 Best-effort is the default mode for all traffic.
 There is no differentiation among types of traffic.
 Best-effort model is similar to using standard mail—
“The mail will arrive when the mail arrives.”
 Benefits:
Highly scalable
No special mechanisms required
 Drawbacks:
No service guarantees
No service differentiation
© 2006 Cisco Systems, Inc. All rights reserved.
Integrated Services (IntServ) Model Operation
 Ensures guaranteed delivery and
predictable behavior of the network for
applications.
 Provides multiple service levels.
 RSVP is a signaling protocol to
reserve resources for specified QoS
parameters.
 The requested QoS parameters are
then linked to a packet stream.
 Streams are not established if the
required QoS parameters cannot be
met.
 Intelligent queuing mechanisms
needed to provide resource
reservation in terms of:
Guaranteed rate
Controlled load (low delay, high
throughput)
© 2006 Cisco Systems, Inc. All rights reserved.
IntServ Functions
Control Plane
Routing Selection
Admission Control
Reservation Setup
Reservation Table
Data Plane
Flow Identification
© 2006 Cisco Systems, Inc. All rights reserved.
Packet Scheduler
Benefits and Drawbacks of the IntServ Model
 Benefits:
Explicit resource admission control (end to end)
Per-request policy admission control (authorization object,
policy object)
Signaling of dynamic port numbers (for example, H.323)
 Drawbacks:
Continuous signaling because of stateful architecture
Flow-based approach not scalable to large implementations,
such as the public Internet
© 2006 Cisco Systems, Inc. All rights reserved.
Resource Reservation Protocol (RSVP)
 Is carried in IP—protocol ID
46
 Can use both TCP and UDP
port 3455
 Is a signaling protocol and
works with existing routing
protocols
 Requests QoS parameters
from all devices between the
source and destination
Sending
Host
RSVP
Tunnel
RSVP Receivers
 Provides divergent performance requirements for multimedia
applications:
Rate-sensitive traffic
Delay-sensitive traffic
© 2006 Cisco Systems, Inc. All rights reserved.
RSVP Daemon
Policy
Control
Admission
Control
RSVP
Daemon
Reservation
Routing
Data
© 2006 Cisco Systems, Inc. All rights reserved.
Packet
Classifier
Packet
Scheduler
Reservation Merging
R3
R5
R5
R4
R4
Sender
R2
R1
 R1, R2 and R3 all request the same reservation.
 The R2 and R3 request merges at R4.
 The R1 request merges with the combined R2 and R3 request at R5.
 RSVP reservation merging provides scalability.
© 2006 Cisco Systems, Inc. All rights reserved.
RSVP in Action
 RSVP sets up a path through the network with the requested QoS.
 RSVP is used for CAC in Cisco Unified CallManager 5.0.
© 2006 Cisco Systems, Inc. All rights reserved.
The Differentiated Services Model
 Overcomes many of the limitations best-effort and IntServ models
 Uses the soft QoS provisioned-QoS model rather than the hard QoS
signaled-QoS model
 Classifies flows into aggregates (classes) and provides appropriate QoS for
the classes
 Minimizes signaling and state maintenance requirements on each network
node
 Manages QoS characteristics on the basis of per-hop behavior (PHB)
 You choose the level of service for each traffic class
Edge
End Station
Edge
Interior
Edge
DiffServ Domain
© 2006 Cisco Systems, Inc. All rights reserved.
End Station
Self Check
1. Which of the QoS models is more scalable, yet still
provides QoS for sensitive traffic?
2. Which QoS model relies on RSVP?
3. What are some drawbacks of using IntServ for QoS?
4. What is admission control?
5. What are the drawbacks of using Diffserv?
© 2006 Cisco Systems, Inc. All rights reserved.
Summary
 Best effort QoS is appropriate where sensitive traffic
does not have to be services. When sensitive traffic
must be services, IntServ or Diffserv should be used to
provide QoS.
 IntServ uses RSVP to guarantee end to end services
for a traffic flow. RSVP has significant signaling
overhead and is not highly scalable.
 Diffserv uses classes to identify traffic and then
provides QoS to those classes. Diffserv is highly
scalable, but does not provide a service guarantee.
© 2006 Cisco Systems, Inc. All rights reserved.
Resources
 Resource Reservation Protocol (RSVP) – from the
Cisco Internetworking Technology Handbook
http://cisco.com/en/US/partner/tech/tk1330/tsd_technology_sup
port_technical_reference_chapter09186a0080759873.html
 Quality of Service – from the Cisco Internetworking
Technology Handbook
http://cisco.com/en/US/partner/tech/tk1330/tsd_technology_sup
port_technical_reference_chapter09186a0080759886.html
© 2006 Cisco Systems, Inc. All rights reserved.
Optimizing Converged
Cisco Networks (ONT)
Module 3: Introduction to IP QoS
© 2006 Cisco Systems, Inc. All rights reserved.
Lesson 3.4: Using
MQC for
Implementing QoS
© 2006 Cisco Systems, Inc. All rights reserved.
Objectives
 Identify the features of each method for QoS policy
implementation.
 Describe the guidelines for using CLI to implement QoS
policy.
 Describe the Modular QoS Command Line (MQC)
© 2006 Cisco Systems, Inc. All rights reserved.
Methods for Implementing QoS Policy
Method
Legacy CLI
Description
– Coded at the CLI
– Requires each interface to be individually
configured
– Time-consuming
MQC
– Coded at the CLI
– Uses configuration modules
– Best method for QoS fine tuning
Cisco AutoQoS
– Applies a possible QoS configuration to the
interfaces
– Fastest way to implement QoS
Cisco SDM QoS wizard
© 2006 Cisco Systems, Inc. All rights reserved.
– Application for simple QoS configurations
Configuring QoS at the CLI
 Uses the CLI via console and Telnet
 Traditional method
 Nonmodular
 Cannot separate traffic classification from policy
definitions
 Time-consuming and potentially error-prone task
 Used to augment and fine-tune newer Cisco AutoQoS
method
© 2006 Cisco Systems, Inc. All rights reserved.
Guidelines for Using the CLI
Configuration Method
 Build a traffic policy:
Identify the traffic pattern.
Classify the traffic.
Prioritize the traffic.
Select a proper QoS mechanism:
Queuing
Compression
 Apply the traffic policy to the interface.
© 2006 Cisco Systems, Inc. All rights reserved.
Legacy CLI QoS Example











interface multilink
ip address 10.1.61.1 255.255.255.0
load-interval 30
custom-queue-list 1
ppp multilink
ppp multilink fragment-delay 10
ppp multilink interleave
multilink-group 1
ip tcp header-compression iphc-format
!
queue-list 1 protocol ip 2 tcp 23
 For interactive traffic, you can use CQ and TCP header compression.
© 2006 Cisco Systems, Inc. All rights reserved.
Modular QoS CLI
 A command syntax for configuring QoS policy
 Reduces configuration steps and time
 Configures policy, not “raw” per-interface commands
 Uniform CLI across major Cisco IOS platforms
 Uniform CLI structure for all QoS features
 Separates classification engine from the policy
© 2006 Cisco Systems, Inc. All rights reserved.
Modular QoS CLI Components
© 2006 Cisco Systems, Inc. All rights reserved.
Step 1: Creating Class Maps:
“What Traffic Do We Care About?”
 Each class is identified using a class map.
 A traffic class contains three major elements:
A case-sensitive name
A series of match commands
An instruction on how to evaluate the match commands if more
than one match command exists in the traffic class
 Class maps can operate in two modes:
Match all: All conditions have to succeed.
Match any: At least one condition must succeed.
 The default mode is match all.
© 2006 Cisco Systems, Inc. All rights reserved.
Configuring Class Maps
 Enter class-map configuration mode. Specify the matching strategy.
router(config)#
class-map [match-all | match-any] class-map-name
 Use at least one condition to match packets.
router(config-cmap)#
match any
match not match-criteria
 Use descriptions in large and complex configurations. The
description has no operational meaning.
router(config-cmap)#
description description
© 2006 Cisco Systems, Inc. All rights reserved.
Classifying Traffic with ACLs
 Standard ACL
router(config)#
access-list access-list-number {permit | deny | remark}
source [mask]
 Extended ACL
router(config)#
access-list access-list-number {permit | deny} protocol
source source-wildcard [operator port] destination
destination-wildcard [operator port] [established] [log]
 Use an ACL as a match criterion
router(config-cmap)#
match access-group access-list-number
© 2006 Cisco Systems, Inc. All rights reserved.
Step 2: Policy Maps:
“What Will Be Done to This Traffic?”
 A policy map defines a traffic policy, which configures
the QoS features associated with a traffic class that
was previously identified using a class map.
 A traffic policy contains three major elements:
A case-sensitive name
A traffic class
The QoS policy that is associated with that traffic class
 Up to 256 traffic classes can be associated with a
single traffic policy.
 Multiple policy maps can be nested to influence the
sequence of QoS actions.
© 2006 Cisco Systems, Inc. All rights reserved.
Configuring Policy Maps
 Enter policy-map configuration mode. Policy maps are identified by a
case-sensitive name.
router(config)#
policy-map policy-map-name
 Enter the per-class policy configuration mode by using the name of a
previously configured class map. Use the class-default name to configure
the policy for the default class.
router(config-pmap)#
class {class-name | class-default}
 Optionally, you can define a new class map by entering the condition after
the name of the new class map. Uses the match-any strategy.
router(config-pmap)#
class class-name condition
© 2006 Cisco Systems, Inc. All rights reserved.
Step 3: Attaching Service Policies:
“Where Will This Policy Be Implemented?”
 Attach the specified service policy map to the input or
output interface
router(config-if)#
service-policy {input | output} policy-map-name
class-map HTTP
match protocol http
!
policy-map PM
class HTTP
bandwidth 2000
class class-default
bandwidth 6000
!
interface Serial0/0
service-policy output PM
© 2006 Cisco Systems, Inc. All rights reserved.
Service policies
can be applied to
an interface for
inbound or
outbound
packets
Modular QoS CLI Configuration Example
1
router(config)# class-map match-any business-critical-traffic
router(config-cmap)# match protocol http url “*customer*”
router(config-cmap)# match protocol http url citrix
2
router(config)# policy-map myqos policy
router(config-pm am)# class business-critical-traffic
router(config-pm am-c)# bandwidth 1000
interface serial 0/0
3 router(config)#
router(config-if)# service-policy output myqos policy
© 2006 Cisco Systems, Inc. All rights reserved.
Boolean Nesting
Goal
Salaries
Football
Players
Goal:
Hockey
Players
Find books that cover the salaries of either
football players or hockey players.
Solution: Boolean (salaries AND [football players OR
hockey players]).
© 2006 Cisco Systems, Inc. All rights reserved.
MQC Example
 Voice traffic needs priority, low delay, and constant
bandwidth.
 Interactive traffic needs bandwidth and low delay.
© 2006 Cisco Systems, Inc. All rights reserved.
MQC Configuration
hostname Office
!
class-map VoIP
match access-group 100
Classification
class-map Application
match access-group 101
!
policy-map QoS-Policy
class VoIP
priority 100
class Application
QoS Policy
bandwidth 25
class class-default
fair-queue
!
interface Serial0/0
QoS Policy on Interface
service-policy output QoS-Policy
!
access-list 100 permit ip any any precedence 5
access-list 100 permit ip any any dscp ef
Classification
access-list 101 permit tcp any host 10.1.10.20
access-list 101 permit tcp any host 10.1.10.40
© 2006 Cisco Systems, Inc. All rights reserved.
Basic Verification Commands
 Display the class maps
router#
show class-map
 Display the policy maps
router#
show policy-map
 Display the applied policy map on the interface
router#
show policy-map interface type number
© 2006 Cisco Systems, Inc. All rights reserved.
Summary
 There are 4 basic ways to implement QoS policy on Cisco devices:
CLI, MQC, AutoQoS and SDM. Choosing a method will depend on
the complexity of the network on the expertise of the administrator.
 The Cisco MQC offers significant advantages over the legacy CLI
method for implementing QoS. By using MQC, a network
administrator can significantly reduce the time and effort it takes to
configure QoS in a complex network.
 There are three steps to follow when configuring QoS using Cisco
MQC configuration. Each step answers a question concerning the
classes assigned to different traffic flows:
What traffic do we care about?
What will happen to the classified traffic?
Where will the policy apply?
© 2006 Cisco Systems, Inc. All rights reserved.
Self Check
1. What is a class map?
2. How many class maps can be configured on a Cisco
router?
3. What is a traffic policy?
4. What are the 3 basic elements of a traffic policy?
5. What command is used to assign a policy map to an
interface?
© 2006 Cisco Systems, Inc. All rights reserved.
Q and A
© 2006 Cisco Systems, Inc. All rights reserved.
Resources
 Modular Quality of Service Command-Line Interface
http://www.cisco.com/en/US/partner/products/sw/iosswrel/ps50
14/products_feature_guide_book09186a0080088141.html
 QoS Policing: Cisco Modular Quality of Service
Command Line Interface
http://www.cisco.com/en/US/partner/tech/tk543/tk545/technologi
es_white_paper09186a0080123415.shtml
© 2006 Cisco Systems, Inc. All rights reserved.
Optimizing Converged
Cisco Networks (ONT)
Module 3: Introduction to IP QoS
© 2006 Cisco Systems, Inc. All rights reserved.
Lesson 3.5:
Implementing QoS
with Cisco AutoQoS
© 2006 Cisco Systems, Inc. All rights reserved.
Objectives
 Describe LAN and WAN features of Cisco AutoQoS.
 Identify the guidelines when using Cisco AutoQoS to
implement QoS policies.
 Describe the features of the Cisco Security Device
Manager (SDM).
 Explain how SDM can be used to implement QoS on
Cisco devices.
 Compare and contrast four methods for configuring
QoS on a network.
© 2006 Cisco Systems, Inc. All rights reserved.
Cisco AutoQoS
© 2006 Cisco Systems, Inc. All rights reserved.
Cisco AutoQoS Features in a WAN
Feature
Autodetermination of
WAN Settings
Autoclassification of
VoIP Settings
Benefit
Eliminates the need to know QoS theory and design
in common deployment scenarios
Automatically classifies RTP payload and VoIP
control packets (H.323, H.225 unicast, Skinny, SIP),
and MGCP
Initial Policy
Reduces the time needed to establish an initial,
Generation
feasible QoS policy solution
VoIP LLQ
Provisions LLQ for the VoIP bearer and bandwidth
Provisioning
guarantees for control traffic
WAN Traffic Shaping Enables WAN traffic shaping (FRTS, CIR and burst)
Link Efficiency
Enables link efficiency mechanisms (LFI and cRTP)
as appropriate
Management
Provides SNMP and syslog alerts for VoIP packet
drops
© 2006 Cisco Systems, Inc. All rights reserved.
Cisco AutoQoS Features in a LAN
Feature
Benefit
Simplified
Configuration
One-command voice configuration does not affect other network
traffic. Can be fine tuned.
Queue
Configuration
Configures queue admission criteria, Cisco Catalyst strict-priority
queuing with WRR scheduling, modifies queue sizes and
weights.
Automated &
Secure
Detects Cisco IP Phones and enables AutoQoS settings.
Protects against malicious activity during Cisco IP phone
relocations and moves.
Optimal VoIP
Performance
Leverages decades of networking experience and uses all
advanced QoS capabilities of the Cisco Catalyst switches.
End-to-End
Interoperability
Works with AutoQoS settings on all other Cisco switches and
routers.
Trust Boundary
Enforcement
Enforces the trust boundary on Cisco Catalyst switch access
ports, uplinks, and downlinks
NBAR Support
Enables NBAR for different traffic types
© 2006 Cisco Systems, Inc. All rights reserved.
Cisco AutoQoS Use Guidelines
 Make sure that:
Any QoS configurations on the WAN interface are removed.
CEF is enabled.
NBAR is enabled.
Correct bandwidth statement is configured on the interface.
Cisco AutoQoS is enabled on the interface.
© 2006 Cisco Systems, Inc. All rights reserved.
Cisco AutoQoS Example
 Enable Cisco AutoQoS on relevant devices (such as LAN switches and WAN
routers) that need to perform QoS.
© 2006 Cisco Systems, Inc. All rights reserved.
Cisco AutoQoS Example (Cont.)
 interface Serial1/3
 ip cef
IP CEF and Bandwidth
 bandwidth 1540
 ip address 10.10.100.1 255.255.255.0
 auto qos voip
AutoQoS for VoIP Traffic Recognized by NBAR
© 2006 Cisco Systems, Inc. All rights reserved.
Cisco Security Device Manager (SDM)
© 2006 Cisco Systems, Inc. All rights reserved.
Steps 1 to 4: Creating a QoS Policy
1.
3.
2.
4.
© 2006 Cisco Systems, Inc. All rights reserved.
Step 5: Launching the QoS Wizard
© 2006 Cisco Systems, Inc. All rights reserved.
Step 6: Selecting the Interface
© 2006 Cisco Systems, Inc. All rights reserved.
Step 7: Generating a QoS Policy
© 2006 Cisco Systems, Inc. All rights reserved.
Reviewing the QoS Configuration
© 2006 Cisco Systems, Inc. All rights reserved.
Completing the Configuration: Command
Delivery Status
© 2006 Cisco Systems, Inc. All rights reserved.
Monitoring QoS Status
1.
A
B
2.
© 2006 Cisco Systems, Inc. All rights reserved.
Comparing QoS Implementation Methods
Legacy CLI
MQC
Cisco
AutoQoS
Cisco SDM
QoS Wizard
Ease of use
Poor
Moderately
easy
Simple
Simple
Ability to
fine-tune
Acceptable
Very good
Limited
Limited
Time to
implement
Longest
Average
Shortest
Short
Modularity
Poor
Excellent
Excellent
Very good
© 2006 Cisco Systems, Inc. All rights reserved.
Summary
 Cisco AutoQoS simplifies and shortens the QoS
deployment cycle. Cisco AutoQoS helps in all of the
five major aspects of successful QoS deployments.
 Cisco AutoQoS simplifies deployment and speeds
provisioning of Quality of Service technology over a
Cisco network infrastructure. It reduces human error
and lowers training costs.
 Cisco Security Device Manager (SDM) is an intuitive,
web-based device management tool that was created
for easy and reliable deployment and management of
Cisco IOS routers.
© 2006 Cisco Systems, Inc. All rights reserved.
Self Check
1. What are the requirements that must be met in order
to run AutoQoS?
2. What command is used to enable AutoQoS on an
interface?
3. What traffic classes are supported by SDM?
4. Which method of configuring QoS is the hardest to
implement, requires the most time and offers the least
modularity?
© 2006 Cisco Systems, Inc. All rights reserved.
Q and A
© 2006 Cisco Systems, Inc. All rights reserved.
Resources
 Cisco AutoQoS Q&A
http://www.cisco.com/en/US/partner/tech/tk543/tk759/tk879/tec
hnologies_q_and_a_item0900aecd8020a589.shtml
 SDM Demo Lab (Live Demo)
http://www.cisco.com/en/US/partner/products/sw/secursw/ps53
18/prod_presentation0900aecd802adc65.html
 Cisco SDM Multimedia Demo
http://www.cisco.com/cdc_content_elements/flash/sdm/sdm.exe
 SDM Presentations (VoDs)
http://www.cisco.com/en/US/partner/products/sw/secursw/ps53
18/prod_presentation_list.html
 SDM Homepage
http://www.cisco.com/en/US/products/sw/secursw/ps5318/
© 2006 Cisco Systems, Inc. All rights reserved.
© 2006 Cisco Systems, Inc. All rights reserved.