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 Manual QoS 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 AutoQoS interface Serial0 bandwidth 256 ip address 10.1.61.1 255.255.255.0 auto qos voip
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 switch(config-if)# auto qos voip trust 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 switch(config-if)# auto qos voip cisco-phone 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 router(config-if)# auto discovery qos [trust] 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.
Enabling Auto Discovery Example 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 Specify bandwidth, IP address and FR DLCI Enable Auto Discovery Frame Relay 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.
Reviewing the Auto Discovery Generated QoS Policy Statistics show auto discovery qos Frame Relay 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) Detected applications and data: Application/ AverageRate PeakRate Total Protocol (kbps/%) (kbps/%) (bytes) rtp video 24/2 5337/52 704574 Class Transactional: Recommended Minimum Bandwidth: 0 Kbps/0% (AverageRate) Detected applications and data: Application/ AverageRate PeakRate Total Protocol (kbps/%) (kbps/%) (bytes) citrix 36/3 74/7 30212 sqlnet 12/1 7/<1 1540
Phase 2: Configuring QoS Policies on Routers router(config-if)# auto qos [voip [trust] [fr-atm]] 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.
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 Examine Auto Discovery results: P r o c e d u r e n t e r p r V o I show auto discovery qos Examine Cisco AutoQoS templates and initial configuration: show auto qos Explore interface statistics for autogenerated policy: show policy-map interface Examine Cisco AutoQoS templates and initial configuration: show auto qos Explore interface-level autogenerated QoS parameters: show policy-map interface F l o w i s e P Examine CoS-to-DSCP maps: show mls qos maps
Monitoring Cisco AutoQoS on a Router: Step 1 router# show auto discovery qos [interface [interface type]] 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). Detected applications and data: Application/ AverageRate PeakRate Total Protocol (kbps/%) (kbps/%) (bytes) --------- ---------- ------- -------- rtp audio 2/<1 517/50 703104 <...rest of the output deleted...>
Monitoring Cisco AutoQoS on a Router: Step 2 router# show auto qos [interface interface type] 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 bandwidth remaining percent 5 set dscp cs4 class AutoQoS-Transactional-Se2/1.1 bandwidth remaining percent 5 <...rest of the output deleted...>
Monitoring Cisco AutoQoS on a Router: Step 3 router# show policy-map interface [interface type] Displays the packet statistics of all classes that are configured for all service policies on the specified interface, subinterface, or PVC 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 - <...rest of the output deleted...>
Monitoring Cisco AutoQoS on a Switch: Step 1 switch# show auto qos [interface interface-id] Displays the Cisco AutoQoS VoIP configuration that was initially applied Does not display any user changes to the configuration that might be in effect 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 20% of leftover by queue 4 80% of leftover by queue 4 CoS High Priority Not used
Monitoring Cisco AutoQoS on a Switch: Step 2 switch# show mls qos interface [interface-id vlan vlan-id] [buffers policers queueing statistics] Displays QoS information at the interface level 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...>
Monitoring Cisco AutoQoS on a Switch: Step 3 switch# show mls qos maps [cos-dscp dscp-cos] Displays the maps that are used to generate an internal DSCP value, to represent the priority of the traffic 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
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_p rotocol_option_home.html Cisco AutoQoS Q&A http://cisco.com/en/us/partner/tech/tk543/tk759/tk879/technolo gies_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 eventmonitoring 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 Shaping Congestion avoidance Link efficiency Percentage-based LLQ and CBWFQ WRR Class-based shaping or FRTS WRED Header compression and link fragmentation and interleaving (10ms) Provides EF treatment for voice, AF treatment for video and data, and besteffort treatment as default Shapes to CIR to prevent bursts and smooth traffic to configured rate Makes intelligent packet drop decisions to prevent tail drops across multiple TCP sessions Reduces VoIP bandwidth requirement and jitter experienced by voice packets
Automated Cisco AutoQoS up to 10 DiffServ Class Provisioning Auto Discovery Application and Protocol-Types Offered Bit Rate (Average and Peak) Cisco Auto QoS Policy Cisco Auto QoS Classmaps Match Statements Minimum Bandwidth to Class Queues, Scheduling and WRED Traffic Class DSCP CoS IP routing CS6 6 Interactive voice EF 5 Interactive video AF41 4 Streaming video CS4 4 Telephony signaling CS3 3 Transactionalinteractive Network management AF21 2 CS2 2 Bulk data AF11 1 Scavenger CS1 1 Best effort 0 0
Common Issues with Cisco AutoQoS Issue Cisco AutoQoS generates up to 10 classes, but most enterprise networks deploy 3 6 classes today. Cisco AutoQoS does not adapt to changing traffic conditions automatically. Cisco AutoQoS does not handle all possible scenarios that may occur and might not fit specific classification or policies. Solution Manual consolidation of similar classes to meet the final number of classes actually needed. Running Auto Discovery on a periodic basis followed by reenabling of Cisco AutoQoS. 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)?
How to Interpret the show auto qos Command Output LLQ Class-Based Marking CBWFQ Class-Based Shaping NBAR 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 bandwidth remaining percent 10 set dscp af41 class AutoQoS-Transactional-Se2/1.1 bandwidth remaining percent 5 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...> Nested Policy Map (Frame Relay) Parent Policy Map (Frame Relay) Classification
How to Interpret the show auto qos Command Output (Cont.) Monitoring Drops in LLQ Thresholds are activated in RMON alarm table to monitor drops in Voice Class. The default drop threshold is 1 bps. 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. Frame Relay RMON event generated by AutoQoS 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
How to Interpret the show auto qos Command Output (Cont.) RMON Traps for Voice Packet Drops 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 Applying all to the DLCI (or Policy Map to the Serial in Non-Frame Relay) frame-relay bc 10240 Frame Relay Traffic Parameters frame-relay be 0 frame-relay mincir 1024000 service-policy output AutoQoS-Policy-Se2/1.1-Parent
When Is Manual Modification of AutoQoS Configuration Required?
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. 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 H.323 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 MGCP
MCQ Classification Options router(config-cmap)# 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 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.
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 http://cisco.com/en/us/partner/products/ps6656/products_ios_p rotocol_option_home.html Cisco AutoQoS Q&A http://cisco.com/en/us/partner/tech/tk543/tk759/tk879/technolo gies_q_and_a_item0900aecd8020a589.shtml