Transcript class-map

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.