ILTA HAND 8 QoS/CoS, Cisco 2011Systems, Inc. www.cisco.com Agenda Remember this is a 101 class. What is it? Do you need QoS? Explain QoS Lab Real World Examples Q&A What is it? Quality of service is the ability to provide different priority to different applications, users, or data flows. Classifying VoIP Signaling and Media with DSCP for QoS http://www.cisco.com/en/us/docs/ios/12_2t/12_2t2/feature/guide/ft_dscp. / /US/d /i /12 2t/12 2t2/f t / id /ft d html Quality of Service (QoS) http://www.cisco.com/en/us/products/ps6558/products_ios_technology_home.html
Why Enable QoS? ISN T QOS AN OPTIONAL LUXURY TECHNOLOGY? Necessity Luxury Security Quality of Service High Availability Why Enable QoS? HA, Security, and QoS Are Interdependent Technologies Security High Availability Quality of Service QoS: Enables IP Telephony and Video Drives productivity by enhancing service-levels to mission-critical applications Cuts costs by bandwidth optimization Helps maintain network availability in the event of DoS/worm attacks Challenges of Packet Voice Sources of quality problems in Voice and Video over Data: Loss Delay Delay Variation (Jitter)
Enterprise QoS Remote site has a 1350 Kbps CIR FR link Bursty applications contending for bandwidth reduce collective throughput. Customer needs better throughput What can we do to improve things? 130 Kbps 1300 Kbps C i s c o Q o S A r c h i t e c t u r a l F r a m e w o r k Business Objectives Voice Video Data QoS for Security QoS for Tiered Services QoS for Convergence DiffServ Standards Hybrid Standards IntServ Standards Architecture Standards QoS Detailed, Cisco 2011Systems, Inc. www.cisco.com
QoS Terms CoS - Class of Service, Layer 2 (802.1p) ToS - Type of Service, Layer 3 (IP Precedence) DSCP - Differentiated Services Code Point (DiffServ) PHB - Per-Hop Behavior (packet scheduling, queuing, policing, or shaping behavior) EF - Expedited Forwarding AF - Assured Forwarding CS - Class Selector BE - Best Effort Scavenger Class with lowest configurable queuing service CAC - Call Admission Control Version Length Enabling QoS in the Campus Layer 3 Classification: IP Precedence, DSCP ToS Byte Len ID Offset TTL Proto FCS IP SA IP DA Data IPv4 Packet 7 6 5 4 3 2 1 0 IP Precedence Unused DiffServ Code Point (DSCP) Flow Ctrl Standard IPv4 DiffServ Extensions IPv4: Three most significant bits of ToS byte are called IP precedence other bits unused by IP Precedence DiffServ: Six most significant bits of ToS byte are called DiffServ Code Point (DSCP) Remaining two bits used for flow control DSCP is backward-compatible with IP precedence DSCP values correspond to Per Hop Behavior (PHB) designations RFC 2474 provides more information on DSCP IP Precedence IP Precedence marks packets into six classes (two reserved): Number Name 0 routine 1 priority 2 immediate 3 flash 4 flash-override 5 critical 6 internet reserved 7 network reserved 2951 IP Precedence is used to determine the weight for QoS policy, for example for WFQ, WRED Server PBX 3945 6500 Handset GSR 3945 6500 Server
Enabling QoS in the Campus Classification Summary L2 CoS IP Prec. L3 Classification PHB DSCP Application 7 6 5 4 3 2 1 0 * Including audio and video 7 6 5 4 3 2 1 0 - - EF AF41 56-63 48-55 46 34 AF31 CS3 26 24 AF2y AF1y BE 18,20,22 10,12,14 IETF recommendations Reserved Reserved Voice Bearer Video Conferencing* Call Signaling High Priority Data Medium Priority Data 0 Best Effort Data DiffServ Behaviors Expedited Forwarding (EF) PHB, low loss, low latency and jitter, assured bandwidth, end-end service DSCP = 101110 Assured Forwarding (AF) PHB, four classes DSCP = 001dd0, 010dd0, 011dd0, or 100dd0, where dd is the drop preference within the class Default PHB, best-effort behavior (ideally some minimum resources allocated) DSCP = 000000 Backwards compatible with precedence How Is QoS Optimally Deployed? 1. Strategically define the business objectives to be achieved via QoS 2. Analyze the service-level l requirements of the various traffic classes to be provisioned for 3. Design and test the QoS policies prior to production-network rollout 4. Roll-out the tested QoS designs to the production-network in phases, during 2011 Cisco Systems, scheduled Inc. All rights reserved. downtime
Data QoS Requirements Provisioning for Data Different applications have different traffic characteristics Different versions of the same application can have different traffic characteristics Classify data into four/five data classes model: Mission-critical apps Transactional/interactive apps Bulk data apps Best effort apps Optional: Scavenger apps Data Smooth/bursty Benign/greedy Drop insensitive Delay insensitive TCP retransmits Data Q os Requirements Provisioning for Data (Cont.) Use four/five main traffic classes: Mission-critical apps business-critical client-server applications Transactional/interactive apps foreground apps: client-server apps or interactive applications Bulk data apps background apps: FTP, e-mail, backups, content distribution Best effort apps (default class) Optional: Scavenger apps peer-to-peer apps, gaming traffic Additional optional data classes include internetwork-control (routing) and network-management Most apps fall under best-effort, make sure that adequate bandwidth is provisioned for this default class How Many Classes of Service Do I Need? Example Strategy for Expanding the Number of Classes of Service over Time 4/5 Class Model 8 Class Model QoS Baseline Model Realtime Call Signaling Critical Data Best Effort Voice Video Call Signaling Network Control Critical Data Bulk Data Best Effort Voice Interactive-Video Streaming Video Call Signaling IP Routing Network Management Mission-Critical Data Transactional Data Bulk Data Best Effort Scavenger Time Scavenger Scavenger
Classification and Marking Design QoS Baseline Marking Recommendations L3 Classification L2 Application IPP PHB DSCP CoS Routing 6 CS6 48 6 Voice 5 EF 46 5 Video Conferencing 4 AF41 34 4 Streaming Video 4 CS4 32 4 Mission-Critical Data 3 AF31* 26 3 Call Signaling 3 CS3* 24 3 Transactional Data 2 AF21 18 2 Network Management 2 CS2 16 2 Bulk Data 1 AF11 10 1 Scavenger 1 CS1 8 1 Best Effort 0 0 0 0 Campus Queuing Design Realtime, Best Effort, and Scavenger Queuing Rules Best Effort 25% Real-Time 33% Scavenger/Bulk 5% Critical Data Enabling QoS in the Campus Layer 2 Classification: 802.1p, CoS Pream. SFD DA Three Bits Used for CoS (802.1p User Priority) SA PRI Type CFI TAG 4 bytes 802.1p user priority field also called Class of Service (CoS) Different types of traffic are assigned different CoS values CoS 6 and 7 are reserved for network use * Including Audio and Video PT VLAN ID Data 802.1Q/p Header FCS Ethernet Frame CoS Application 7 Reserved 6 Reserved 5 Voice Bearer 4 Video Conferencing* 3 Call Signaling 2 High Priority Data 1 Medium Priority Data 0 Best Effort Data
Enabling QoS in the Campus Scheduling in IP Phones IP Phone Enclosure Phone CoS = 5 Voice CoS = 5 Data Access CoS = 0 Priority Q Switch CoS = 5 Data Qs PC Voice media traffic is marked with CoS 5/ DSCP EF (high priority) Data traffic from the PC is re-marked with CoS 0 (low priority) by the IP phone switch; this occurs if PC tags frames as 802.1p/Q; Call Admission Control (CAC) Why CAC? Boat capacity = five persons When the sixth person climbs aboard everybody gets wet! Branch Size Max Calls Actual BW Small 3 240 Kbps Medium 8 640 Kbps Large 16 1,280 Kbps Network Services/ Media Monitoring ILTA 2000, Cisco 2011Systems, Inc. www.cisco.com econ_0386_09_001.ppt
Quality of Experience Lack of Visibility High expenditures with troubleshooting Don t know where the problem is most of the time Cannot replicate problems Inability to assess impact of video, voice and data applications on the network High-bandwidth upgrade costs Inability to verify service level agreements Provides a means to measure, validate, perform fault-isolation and assess the network s ability to deliver high quality voice, video and data. Medianet Media Monitoring is a family of Cisco IOS features that enhances visibility in the Medianet Network: Performance Monitor Mediatrace IP Service-Level Agreement (IP SLA) Video Operation (VO) Performance Monitor Analyzes traffic to measure performance statistics like loss, delay, jitter, and others. Statistics can be accessed by NetFlow or MIB. Relevant for video, voice and data traffic. Alarms created based on exceeded thresholds.
Mediatrace Discovers an IP flow s path in the network. Dynamically enables monitoring. Collects information on a hop-byhop basis. Collect Performance Monitor stats. Locates degradation along the flow path. IP SLA Video Operation Assesses readiness of the network. Stresses the network path with realistic application-specific media streams. Enables testing the network to ensure configurations are correct for richmedia. Helps guide admin to verify problems were corrected. Using Performance Monitor, Mediatrace and IPSLA VO Together VERIFYING PROBLEM DETECTED. NETWORK RUNNING CORRECT PATH IPSLA VO AND RESOLVED. STATUS: CONFIRMED MEDIATRACE GOOD I ve An got issue Yes. another If was you It looks seen like, video good. by I can Performance meeting run I also IPSLA checked today. VO Monitor and via Mediatrace the time. My last Let video me session verify the had network quality state problems! using IPSLA VO. Can you Fault make was sure periodically identified that it will the work and correct until well? fixed your path by meeting is our being engineers. starts taken.
Summary Media Monitoring provides a means to measure, validate, perform fault-isolation and assess the network s ability to deliver high quality voice, video and data. 3 features: Performance Monitor, Mediatrace, and IP Service-Level Agreement (IP SLA) Video Operation (VO). Reduces operating costs by: Accelerating troubleshooting times Enabling users to make informed decisions with respect to the network based on actual performance data Enabling validation of network with realistic video traffic profiles Lab www.cisco.com PacketTracer Open Cisco Packet Tracer on your desktop. Go to File then Open Find file ILTA QoS 101.pkt
Chicago Switch0 Click on switch0 and highlight the "CLI" tab. Hit "Enter" Switch0> Switch0>enable Switch0# Switch0#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Switch0(config)# Switch0(config)#mls qos (enables quality of service (QoS) functionality globally) Chicago Switch0 cont. Switch0(config)#interface FastEthernet0/1 Switch0(config-if)#mls qos trust dscp (trust DSCP values coming into this interface) Switch0(config-if)#interface FastEthernet0/3 Switch0(config-if)#mls qos trust dscp Switch0(config-if)#exit Switch0(config)#exit Switch0# Switch0#copy running-config startup-config (saves the configuration) Destination filename [startup-config]? (Hit enter ) Building configuration... [OK] Switch0# Switch0#show running-config Chicago Switch1 Click on switch1 and highlight the "CLI" tab. Hit "Enter" Switch1> Switch1>enable Switch1# Switch1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Switch1(config)# Switch1(config)#mls qos
Chicago Switch1 cont. (1) Switch1(config)#interface FastEthernet0/1 Switch1(config-if)#mls qos trust dscp Switch1(config-if)interface FastEthernet0/2 Switch1(config-if)mls qos trust dscp Switch1(config-if)interface FastEthernet0/3 Switch1(config-if)mls if) qos trust dscp Switch1(config-if)interface FastEthernet0/4 Switch1(config-if)mls qos trust device cisco-phone (trust only a cisco phone plugged into this port) Switch1(config-if)#exit Switch1(config)#exit Chicago Switch1 cont. (2) Switch1# Switch1#copy running-config startup-config Destination filename [startup-config]? (Hit enter ) Building configuration... [OK] Switch1# Switch1#show running-config Chicago Router0 Click on Router0 and highlight the "CLI" tab. Hit "Enter" Chicago> Chicago>enable Chicago# Chicago#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Chicago(config)# Chicago(config)#class-map match-all VoIP (note match-all) Chicago(config-cmap)#match ip dscp ef (expedited forwarding) Chicago(config-cmap)#match protocol http Chicago(config-cmap)#exit Chicago(config-cmap)#class-map match-any VoIP-Control Chicago(config-cmap)#match ip dscp af31 (assured forwarding)
Chicago Router0 cont. (1) Chicago(config-cmap)#policy-map QoS-WAN Chicago(config-pmap)#class VoIP Chicago(config-pmap-c)#priority 600 Chicago(config-pmap-c)#class VoIP-Control Chicago(config-pmap-c)# ( bandwidth 8 Chicago(config-pmap-c)#class class-default Chicago(config-pmap-c)# fair-queue Chicago(config-pmap-c)# set ip dscp default (any packet not matching above, set DSCP to zero) Chicago(config-pmap-c)#exit Chicago(config-pmap)#exit Chicago(config)# Chicago Router0 cont. (2) Apply service policy to the WAN interface. Chicago(config)#interface Serial0/0/0 Chicago(config-if)#service-policy output QoS-Wan %% policy map QoS-Wan not configured Chicago Router0 cont. (3) Service policy is case sensitive Chicago(config-if)#service-policy output QoS-WAN I/f Serial0/0/0 class VoIP requested bandwidth 600 (kbps), available only 375 (kbps)
Chicago Router0 cont. (4) Change policy to use less bandwidth Chicago(config-cmap)#policy-map QoS-WAN Chicago(config-pmap)#class VoIP Chicago(config-pmap-c)#priority c)#priority 320 Try now to apply service policy to the WAN interface. Chicago(config)#interface Serial0/0/0 Chicago(config-if)#service-policy output QoS-WAN Chicago(config-if)#exit Chicago(config)#exit Chi # Run packet simulation Lower right hand corner click the "Stop Watch" tab next to "Realtime". You will see "Simulation" replace "Realtime". Click on "PC 1" in lower left hand corner. Select the "Desktop" tab Click on "Traffic Generator" Scroll down and click "Send" Click "Capture / Forward" button and watch the packet move from network device to device. Note the Envelope has a purple box indicating "Expedited forwarding" (EF). As the packet passes from Chicago to New York the purple box is gone. (QoS markings were removed.) Lower right hand corner click on the "Realtime"tab. Chicago Router0 show policymap Click on Router0 and highlight the "CLI" tab. Chicago#show policy-map interface serial 0/0/0 Service-policy output: QoS-WAN Class-map: VoIP (match-all) 0 packets, 0 bytes (Note these counters are NOT going up.) Class-map: class-default (match-any) 101 packets, 13402 bytes 5 minute offered rate 320 bps, drop rate 0 bps Match: any QoS Set dscp default Packets marked xxxxxxx
Correct the QoS Click on Router0 and highlight the "CLI" tab. Chicago# Chicago#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Chicago(config)# Chicago(config)#class-map match-all VoIP Chicago(config-cmap)#no match protocol http Chicago(config-cmap)#match protocol icmp Run packet simulation again Click "Capture / Forward" button and watch the packet move from network device to device. Note the Envelope has a purple box indicating "Expedited forwarding" (EF). As A the packet passes from Chicago to New York the purple box remains. (QoS markings are preserved.) Router0 show policy-map again Click on Router0 and highlight the "CLI" tab. Chicago#show policy-map interface serial 0/0/0 Serial0/0/0 Service-policy output: QoS-WAN Class-map: VoIP (match-all) 156 packets, 44304 bytes (Note these counters now going up.)
QoS Real World Examples Q&A www.cisco.com www.cisco.com