Optimizing Converged Cisco Networks (ONT) · List the prerequisites when using Cisco Auto QoS. Describe the configuration steps necessary to deploy Cisco Auto QoS on routers and switches

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Optimizing Converged Cisco Networks (ONT)

Module 5: Implement Cisco AutoQoS


Introducing Cisco AutoQoS


Objectives

Describe the features of Cisco Auto QoS.

List the prerequisites when using Cisco Auto QoS.

Describe the configuration steps necessary to deploy Cisco Auto QoS on routers and switches.

Describe the commands used to monitor Auto QoS on routers and switches.


Enterprise QoS Challenges

Enterprise networks work with new traffic types:

IP telephony spreads quickly and requires QoS.

Mission-critical applications need guaranteed bandwidth.

QoS implementation requires significant ―challenging‖ knowledge:

Simple networks require a simple QoS solution that works instantly.

QoS deployment should be cheaper and faster.


Cisco AutoQoS: Automating the Delivery of Network QoS

Cisco AutoQoS—QoS for voice, video, and data:

Uses Cisco IOS built-in intelligence to automate QoS delivery for most common business scenarios

Protects business-critical data applications in the enterprise

Simplifies QoS deployment for real-time traffic

Reduces configuration errors

Makes QoS deployments simpler, cheaper, and faster

Follows DiffServ model and other standards in QoS

Allows customers to retain complete control over their QoS configuration


Cisco AutoQoS


Cisco AutoQoS: Automating the 5 Key Elements of QoS Deployment

1. Application classification:Discovers applications and provides appropriate QoS treatment

2. Policy generation: Autogenerates initial and ongoing QoS policies

3. Configuration: Provides high-level business knobs, and automates QoS in multidevice domain

4. Monitoring and reporting:Generates intelligent, automatic alerts and summary reports

5. Consistency: Enables automatic, seamless interoperability among all QoS features and parameters


Manual QoS Configuration Compared to AutoQoS Configuration

interface Multilink1

ip address 10.1.61.1 255.255.255.0

ip tcp header-compression iphc-format

load-interval 30

service-policy output QoS-Policy

ppp multilink

ppp multilink fragment-delay 10

ppp multilink interleave

multilink-group 1

ip rtp header-compression iphc-format

!

REMAINING 34 LINES LEFT OUT

interface Serial0

bandwidth 256

ip address 10.1.61.1 255.255.255.0

auto qos voip

Manual QoS

AutoQoS


Cisco AutoQoS Evolution

Cisco AutoQoS VoIP:

First phase addressed IP telephony.

One command provisions all basic QoS required.

Support is provided across broad range of platforms (switches and routers).

Cisco AutoQoS for the Enterprise:

Second phase extends capabilities (routers only) for data, voice, and video.

Two QoS deployment stages:

Discovers traffic types, load, and generates policy (NBAR)

Implements the generated policy


Deploying Cisco AutoQoS VoIP on Switches

Commands at the interface level configure Cisco AutoQoS VoIP:

Support for Cisco IP phone and Cisco SoftPhone

Support for Cisco SoftPhone currently only on Cisco Catalyst 6500 Series

Trust boundary disabled when Cisco IP phone is moved

Buffer allocation and egress queuing depend on interface type (Gigabit Ethernet or Fast Ethernet).

It is supported on static, dynamic-access, voice VLAN access, and trunk ports.

CDP must be enabled for Cisco AutoQoS VoIP to function properly.


Configuring Cisco AutoQoS on Cisco Catalyst 2960 (EI) and 3560 Switches

Used for trusted connections

Used to trust the ingress VoIP packet marking

Use if the uplink is connected to a trusted switch or router only

auto qos voip trust

switch(config-if)#

auto qos voip cisco-phone

switch(config-if)#

Used for Cisco IP Phone connections

Enables the trusted boundary feature

Uses CDP to detect the presence or absence of a Cisco IP Phone

QoS markings of incoming packets are trusted only when the Cisco IP phone is detected


Cisco AutoQoS VoIP Switch Configuration Example

Auto Discovery notes:• Command should be enabled on the interface of interest.• Do not change interface bandwidth when running Auto Discovery.• Cisco Express Forwarding must be enabled.• All previously attached QoS policies must be removed from the interface.


Cisco AutoQoS: Router Design Considerations


Configuring Cisco AutoQoS: Router Prerequisites

It cannot be configured if a QoS policy (service policy) is attached to the interface.

Cisco Express Forwarding (CEF) must be enabled at the interface or ATM PVC.

It classifies an interface as low speed (less than or equal to 768 kbps) or high speed (more than 768 kbps):

Correct bandwidth must be configured on all interfaces.

If low speed, an IP address must be configured on the interface.


Comprehensive QoS Deployment in Two Phases

Phase 1: Run Auto Discovery to profile traffic:

Collects data from the offered traffic for several days or weeks as desired

Uses NBAR-based protocol discovery

Performs statistical analysis

Phase 2: Generate and deploy MQC-based QoS policies:

Maps applications to their corresponding DiffServ classes

Assigns appropriate values for bandwidth and scheduling parameters


Phase 1: Traffic Profiling on Routers with Auto Discovery

Trust Boundary

Traffic Classification and

DSCP Marking

(NBAR, ACLs, MQC Policy)

DSCP-Marked Packets Process begins discovering and collecting data for Cisco AutoQoS for Enterprise only.

Auto Discovery is enabled on the interface of interest.

Optional trust keyword is used to trust (rely on) the DSCP markings; if unspecified, NBAR will be used.

Default value is untrusted.

Auto Discovery results can be seen with the show auto discovery qos command.

auto discovery qos [trust]

router(config-if)#


interface Serial4/0 point-to-point Encapsulation frame-relay

bandwidth 256

ip address 10.1.71.1 255.255.255.0

frame-relay interface-dlci 100

auto discovery qos

Auto Discovery:

–Command should be enabled on interface of interest.

–Do not change interface bandwidth when running Auto Discovery.

–Cisco Express Forwarding must be enabled.

–All previously attached QoS policies must be removed from the interface.

Enabling Auto Discovery Example

Frame Relay

Specify bandwidth, IP address and FR DLCI

Enable Auto Discovery


show auto discovery qos

AutoQoS Discovery enabled for applications

Discovery up time: 2 days, 55 minutes

AutoQoS Class information:

Class VoIP:

Recommended Minimum Bandwidth: 517 Kbps/50% (PeakRate)

Detected applications and data:

Application/ AverageRate PeakRate Total

Protocol (kbps/%) (kbps/%) (bytes)

rtp audio 76/7 517/50 703104

Class Interactive Video:

Recommended Minimum Bandwidth: 24 Kbps/2% (AverageRate)




rtp video 24/2 5337/52 704574

Class Transactional:

Recommended Minimum Bandwidth: 0 Kbps/0% (AverageRate)




citrix 36/3 74/7 30212

sqlnet 12/1 7/<1 1540

Reviewing the Auto Discovery Generated QoS Policy Statistics

Frame Relay


Phase 2: Configuring QoS Policies on Routers

Frame Relay

It generates and installs the QoS policy based on the Auto Discovery results (AutoQoS for Enterprise).

The optional voip keyword configures Cisco AutoQoS VoIP.

Optional trust keyword is used to trust (rely on) the DSCP markings for VoIP classification; if unspecified, NBAR will be used.

Default value is untrusted.

Optional fr-atm keyword enables Cisco AutoQoS VoIP for the low-speed Frame Relay-to-ATM links.

auto qos [voip [trust] [fr-atm]]

router(config-if)#


Cisco AutoQoS for Enterprise: Router Configuration Example

2. Enable Auto Discovery


Configuring Cisco AutoQoS for the Enterprise on a Low-Speed Serial Interface

Router>enable

Router#configure terminal

Router(config)#interface serial1/3

Router(config)# ip address 10.10.100.2 255.255.255.0

Router(config-if)#bandwidth 256

Router(config-if)#auto discovery qos

Router(config-if)#end

Router#

Leave Cisco Auto Discovery running, preferably for several days.

Router#configure terminal

Router(config)#interface serial1/3

Router(config-if)#auto qos

Router(config-if)#exit


How to Verify Cisco AutoQoS on Routers and Switches

Routers Switches

E

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p

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Examine Auto Discovery results:

show auto discovery qos

V

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Examine Cisco AutoQoStemplates and initial configuration:

show auto qos

Examine Cisco AutoQoStemplates and initial configuration:

show auto qos

Explore interface statistics for autogenerated policy:

show policy-map interface

Explore interface-level autogenerated QoS parameters:

show policy-map interface

Examine CoS-to-DSCP maps:

show mls qos maps

Procedure

Flow


Monitoring Cisco AutoQoS on a Router: Step 1

Displays the results of the data collected during the Auto Discovery phase for a specific interface or all interfaces

router#show auto discovery qos

Serial2/1.1

AutoQoS Discovery enabled for applications

Discovery up time: 2 hours, 42 minutes

AutoQoS Class information:

Class Voice:

Recommended Minimum Bandwidth: 517 Kbps/50% (PeakRate).


Application/ AverageRate PeakRate

Total


--------- ---------- ------- --------

rtp audio 2/<1 517/50 703104

<...rest of the output deleted...>

show auto discovery qos [interface [interface type]]

router#



Displays the Cisco AutoQoS templates (policy maps, class maps, and ACLs) created for a specific interface or all interfaces

router#show auto qos

!

policy-map AutoQoS-Policy-Se2/1.1

class AutoQoS-Voice-Se2/1.1

priority percent 70

set dscp ef

class AutoQoS-Inter-Video-Se2/1.1

bandwidth remaining percent 10

set dscp af41

class AutoQoS-Stream-Video-Se2/1.1


set dscp cs4

class AutoQoS-Transactional-Se2/1.1



show auto qos [interface interface type]

router#


router#show policy-map interface FastEthernet0/0.1

FastEthernet0/0.1

Service-policy output: voice_traffic

Class-map: dscp46 (match-any)

0 packets, 0 bytes

5 minute offered rate 0 bps, drop rate 0 bps

Match: ip dscp 46

0 packets, 0 bytes

5 minute rate 0 bps

Traffic Shaping

Target Byte Sustain Excess Interval Increment Adapt

Rate Limit bits/int bits/int (ms) (bytes) Active

2500 10000 10000 333 1250 -



Displays the packet statistics of all classes that are configured for all service policies on the specified interface, subinterface, or PVC

show policy-map interface [interface type]

router#


switch#show auto qos

Initial configuration applied by AutoQoS:

wrr-queue bandwidth 20 1 80 0

no wrr-queue cos-map

wrr-queue cos 1 0 1 2 4

wrr-queue cos 3 3 6 7

wrr-queue cos 4 5

mls qos map cos-dscp 0 8 16 26 32 46 48 56

!

interface FastEthernet0/3

mls qos trust device cisco-phone

mls qos trust cos

Monitoring Cisco AutoQoS on a Switch: Step 1

Displays the Cisco AutoQoS VoIP configuration that was initially applied

Does not display any user changes to the configuration that might be in effect

show auto qos [interface interface-id]

switch#

20% of leftover by queue 4 80% of leftover by queue 4

High Priority

Not used

CoS


switch#show mls qos interface gigabitethernet0/1 statistics

Ingress

dscp: incoming no_change classified policed dropped (in bytes)

1 : 0 0 0 0 0

Others: 203216935 24234242 178982693 0 0

Egress

dscp: incoming no_change classified policed dropped (in bytes)

1 : 0 n/a n/a 0 0

WRED drop counts:

qid thresh1 thresh2 FreeQ

1 : 0 0 1024

2 : 0 0 1024

<...rest of the output omitted...>


Displays QoS information at the interface level

show mls qos interface [interface-id | vlan vlan-id]

[buffers | policers | queueing | statistics]

switch#


switch#show mls qos maps dscp-cos

Dscp-cos map:

dscp: 0 8 10 16 18 24 26 32 34 40 46 48 56

-----------------------------------------------

cos: 0 1 1 2 2 3 7 4 4 5 5 7 7


Displays the maps that are used to generate an internal DSCP value, to represent the priority of the traffic

show mls qos maps [cos-dscp | dscp-cos]

switch#


Self Check

1. What is the purpose of Cisco AutoQoS VoIP?

2. What does the auto qos voip cisco-phone

command do?

3. What command is used to display the data collected during auto discovery?


Summary

Cisco AutoQoS provides the user with a simple, intelligent command-line interface (CLI) for enabling campus LAN and WAN QoS for Voice over IP (VoIP) on Cisco switches and routers.

Using Cisco AutoQoS involves 2 phases: discovery and deployment.

Cisco AutoQoS is supported on many routers and switches.


Q and A


Resources

Cisco AutoQoS Introduction

http://cisco.com/en/US/partner/products/ps6656/products_ios_protocol_option_home.html

Cisco AutoQoS Q&A

http://cisco.com/en/US/partner/tech/tk543/tk759/tk879/technologies_q_and_a_item0900aecd8020a589.shtml






Mitigating Common Cisco AutoQoS Issues


Objectives

Describe common issues with Cisco AutoQoS.

Explain how to interpret AutoQoS generated commands.

Determine when manual modification of AutoQoS commands is necessary.

Describe methods for making manual modifications to AutoQoS generated commands.


Major Enterprise QoS Requirements

Trust boundary definition

Identification of applications, protocols of interest (number of classes), and their QoS requirements

Determination of classification options

Determination of traffic-marking options

Determination of queue mechanisms and optimal parameters per class

Definition of port- and interface-specific transport features (TF, MLP, Tx-ring)

Designation of bandwidth efficiency mechanisms for low-speed links (< 768kbps), cRTP, MLP LFI, FRF.12

Identification of efficient alarm and event-monitoring options


Six DiffServ QoS Mechanisms Enabled by Cisco AutoQoS

DiffServ functions are automated and simplified to expedite deployment of QoS features for voice, video, and data.

DiffServ Function Cisco IOS QoS Features Behavior

Classification NBAR and IP precedence

DSCP and CoS

Classifies voice, video, and data traffic based on packet attributes; up to 10 classes

Marking Class-based marking Sets Layer 2 and Layer 3 attributes to separate packets into classes

Congestion management

Percentage-based LLQ and CBWFQ

WRR

Provides EF treatment for voice, AF treatment for video and data, and best-effort treatment as default

Shaping Class-based shaping or FRTS

Shapes to CIR to prevent bursts and smooth traffic to configured rate

Congestion avoidance

WRED Makes intelligent packet drop decisions to prevent tail drops across multiple TCP sessions

Link efficiency Header compression and link fragmentation and interleaving (10ms)

Reduces VoIP bandwidth requirement and jitter experienced by voice packets


Automated Cisco AutoQoS up to 10 DiffServ Class Provisioning

Traffic Class DSCP CoS

IP routing CS6 6

Interactive voice EF 5

Interactive video AF41 4

Streaming video CS4 4

Telephony signaling CS3 3

Transactional-interactive

AF21 2

Network management

CS2 2

Bulk data AF11 1

Scavenger CS1 1

Best effort 0 0

Auto Discovery Cisco Auto QoS Policy

Application and Protocol-Types

Cisco Auto QoS Classmaps

Match Statements

Offered Bit Rate (Average and Peak)

Minimum Bandwidth to Class Queues, Scheduling and WRED


Common Issues with Cisco AutoQoS

Issue Solution

Cisco AutoQoS generates up to 10 classes, but most enterprise networks deploy 3–6 classes today.

Manual consolidation of similar classes to meet the final number of classes actually needed.

Cisco AutoQoS does not adapt to changing traffic conditions automatically.

Running Auto Discovery on a periodic basis followed by re-enabling of Cisco AutoQoS.

Cisco AutoQoS does not handle all possible scenarios that may occur and might not fit specific classification or policies.

Manual fine-tuning of the configuration generated, adding new matching criteria to fit the specific situation.


Interpreting Generated Cisco AutoQoS Configuration

Generated Cisco AutoQoS configuration is examined using show auto qos command, answering these questions:

How many classes were identified (class maps)?

Which traffic classification (class map, match) options were selected?

Which traffic marking options were selected (policy maps, set)?

Which queuing mechanisms and parameters were designated (policy maps, bandwidth, priority)?

Which other QoS mechanisms were appointed per class (policy maps, link efficiency, traffic shaping)?

Were any traffic parameters suggested (frame relay cir, bc)?

Where was the autogenerated policy applied(serial interface, subinterface, DLCI, or PVC)?


router#show auto qos

!

policy-map AutoQoS-Policy-Se2/1.1

class AutoQoS-Voice-Se2/1.1

priority percent 50

set dscp ef

class AutoQoS-Inter-Video-Se2/1.1


set dscp af41

class AutoQoS-Transactional-Se2/1.1


set dscp af21

<...part of the output deleted...>

!

policy-map AutoQoS-Policy-Se2/1.1-Parent

class class-default

shape average 1024000

service-policy AutoQoS-Policy-Se2/1.1

!

class-map match-any AutoQoS-Voice-Se2/1.1

match protocol rtp audio

!

class-map match-any AutoQoS-Transactional-Se2/1.1

match protocol sqlnet

<...part of the output deleted...>

How to Interpret the show auto qos Command Output

Class-BasedShaping

LLQ

Class-BasedMarking

CBWFQ

NBAR

Classification

Nested Policy Map(Frame Relay)

Parent Policy Map(Frame Relay)


How to Interpret the show auto qos Command Output (Cont.)

RMON event generated by AutoQoS

Frame Relay

Monitoring Drops in LLQ

Thresholds are activated in RMON alarm table to monitor drops in Voice Class.

The default drop threshold is 1 bps.

Rmon event 33333 log trap AutoQoS description “AutoQoS

SNMP traps for Voice Drops” owner AutoQoS

Rmon alarm 33350 cbQoSCMDDropBitRate.2881.2991 30

Absolute rising-threshold 1 33333 falling-threshold 0

Owner AutoQoS

SNMP traps generated by Cisco AutoQoS are delivered only if an SNMP server is explicitly enabled and the community string "AutoQoS" is given write permission.


rmon event 33333 log trap AutoQoS description "AutoQoS SNMP

traps for Voice Drops" owner AutoQoS

Serial2/1.1: DLCI 58 -

!

interface Serial2/1.1 point-to-point

frame-relay interface-dlci 58

class AutoQoS-FR-Serial2/1-58

!

map-class frame-relay AutoQoS-FR-Serial2/1-58

frame-relay cir 1024000

frame-relay bc 10240

frame-relay be 0

frame-relay mincir 1024000

service-policy output AutoQoS-Policy-Se2/1.1-Parent

How to Interpret the show auto qos Command Output (Cont.)

Frame Relay Traffic Parameters

RMON Traps for Voice Packet Drops

Applying all to the DLCI(or Policy Map to the Serial in Non-Frame Relay)


When Is Manual Modification ofAutoQoS Configuration Required?


class-map match-any AutoQoS-Voice-Se2/1.1

match protocol rtp audio

!

class-map match-any AutoQoS-Signaling-Se2/1.1

match access-group 101

match protocol rtcp

!

class-map match-any AutoQoS-Transactional-Se2/1.1

match protocol sqlnet

match protocol citrix

!

access-list 101 permit tcp any any eq 1719

access-list 101 permit tcp any any eq 1720

access-list 101 permit udp any any eq 2427

access-list 101 permit udp any any eq 2428

NBAR and ACL Classification Cisco AutoQoS uses NBAR and ACLs to generate classifications

Any MQC classification mechanism can manually tune the generated classification:

Start the Auto Discovery and review the generated results (or take the active classification if Cisco AutoQoS is already activated).

Copy the generated classification and modify it offline.

Apply the modified classification to a router.

H.323

MGCP


MCQ Classification Options

Besides NBAR and ACLs, these major MQC classification options can be used for tuning.

These classification options can be used in any combination as needed to meet specific classification requirements.

match input-interface interface-name

match cos cos-value [cos-value cos-value cos-value]

match ip precedence ip-prec-value [ip-prec ...]

match ip dscp ip-dscp-value [ip-dscp-value ...]

match ip rtp starting-port-number port-range

router(config-cmap)#


Self Check

1. What are some common issues when using Cisco AutoQoS to generate enterprise policies?

2. When is manual Modification of AutoQoS configuration required?


Summary

Cisco AutoQoS automates QoS deployment for the most common enterprise scenarios and enables several Cisco IOS QoS mechanisms to meet the QoS requirements of various applications and traffic types discovered in the enterprise network.

Cisco AutoQoS automatically provisions six QoS mechanisms using DiffServ technology: Classification, Marking, Congestion Management, Shaping, Congestion Avoidance, and Link Efficiency.

Although Cisco AutoQoS automates QoS deployment, it targets only the most common enterprise network scenarios. The QoS classes and templates that Cisco AutoQoS generates will not suit every network requirement.


Q and A


Resources

Cisco AutoQoS Introduction


Cisco AutoQoS Q&A







Documents

Optimizing Converged Cisco Networks (ONT) · List the prerequisites when using Cisco Auto QoS. Describe the configuration steps necessary to deploy Cisco Auto QoS on routers and switches