1. © 2006 Cisco Systems, Inc. All rights reserved. QOS Lecture 5 - QOS Policy Models

2. © 2006 Cisco Systems, Inc. All rights reserved. Three QoS Models ModelCharacteristics Best effortNo QoS is applied to packets. If it is not important when or how packets arrive, the best- effort model is appropriate. Integrated Services (IntServ) Applications signal to the network that the applications require certain QoS parameters. Differentiated Services (DiffServ) The network recognizes classes that require QoS.

3. © 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

4. © 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)

5. © 2006 Cisco Systems, Inc. All rights reserved. IntServ Functions Flow IdentificationPacket Scheduler Data Plane Routing Selection Admission Control Reservation Setup Control Plane Reservation Table

6. © 2006 Cisco Systems, Inc. All rights reserved. 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

7. © 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 Receivers RSVP Tunnel  Provides divergent performance requirements for multimedia applications: Rate-sensitive traffic Delay-sensitive traffic

8. © 2006 Cisco Systems, Inc. All rights reserved. RSVP Daemon Policy Control Admission Control Packet Classifier Packet Scheduler Routing RSVP Daemon Reservation Data

9. © 2006 Cisco Systems, Inc. All rights reserved. Reservation Merging  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. R5 R4 R3 R5 R4 R1 R2 Sender

10. © 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.

11. © 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 Interior Edge DiffServ Domain End Station

12. © 2006 Cisco Systems, Inc. All rights reserved. Methods for Implementing QoS Policy MethodDescription Legacy CLI–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–Application for simple QoS configurations

13. © 2006 Cisco Systems, Inc. All rights reserved. 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

14. © 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.

15. © 2006 Cisco Systems, Inc. All rights reserved. Legacy CLI QoS Example  For interactive traffic, you can use CQ and TCP header compression.  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

16. © 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

17. © 2006 Cisco Systems, Inc. All rights reserved. Modular QoS CLI Components

18. © 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.

19. © 2006 Cisco Systems, Inc. All rights reserved. Configuring Class Maps  Enter class-map configuration mode. Specify the matching strategy. class-map [match-all | match-any] class-map-name router(config)# description router(config-cmap)#  Use at least one condition to match packets.  Use descriptions in large and complex configurations. The description has no operational meaning. match any router(config-cmap)# match not match-criteria

20. © 2006 Cisco Systems, Inc. All rights reserved. Classifying Traffic with ACLs  Standard ACL access-list access-list-number {permit | deny | remark} source [mask] router(config)# access-list access-list-number {permit | deny} protocol source source-wildcard [operator port] destination destination-wildcard [operator port] [established] [log] router(config)# match access-group access-list-number router(config-cmap)#  Extended ACL  Use an ACL as a match criterion

21. © 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.

22. © 2006 Cisco Systems, Inc. All rights reserved. Configuring Policy Maps  Enter policy-map configuration mode. Policy maps are identified by a case-sensitive name. policy-map policy-map-name router(config)# class {class-name | class-default} router(config-pmap)# class class-name condition router(config-pmap)#  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.  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.

23. © 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 service-policy {input | output} policy-map-name router(config-if)# 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 Service policies can be applied to an interface for inbound or outbound packets

24. © 2006 Cisco Systems, Inc. All rights reserved. Modular QoS CLI Configuration Example 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 router(config)# policy-map myqos policy router(config-pm am)# class business-critical-traffic router(config-pm am-c)# bandwidth 1000 router(config)# interface serial 0/0 router(config-if)# service-policy output myqos policy 1 2 3

25. © 2006 Cisco Systems, Inc. All rights reserved. Boolean Nesting Goal: Find books that cover the salaries of either football players or hockey players. Solution: Boolean (salaries AND [football players OR hockey players]). Goal

26. © 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.

27. © 2006 Cisco Systems, Inc. All rights reserved. MQC Configuration hostname Office ! class-map VoIP match access-group 100 class-map Application match access-group 101 ! policy-map QoS-Policy class VoIP priority 100 class Application bandwidth 25 class class-default fair-queue ! interface Serial0/0 service-policy output QoS-Policy ! access-list 100 permit ip any any precedence 5 access-list 100 permit ip any any dscp ef access-list 101 permit tcp any host 10.1.10.20 access-list 101 permit tcp any host 10.1.10.40 Classification QoS Policy QoS Policy on Interface Classification

28. © 2006 Cisco Systems, Inc. All rights reserved. Basic Verification Commands  Display the class maps show class-map router# show policy-map router# show policy-map interface type number router#  Display the policy maps  Display the applied policy map on the interface

29. © 2006 Cisco Systems, Inc. All rights reserved. Cisco AutoQoS

30. © 2006 Cisco Systems, Inc. All rights reserved. Cisco AutoQoS Features in a WAN FeatureBenefit Autodetermination of WAN Settings Eliminates the need to know QoS theory and design in common deployment scenarios Autoclassification of VoIP Settings Automatically classifies RTP payload and VoIP control packets (H.323, H.225 unicast, Skinny, SIP), and MGCP Initial Policy Generation Reduces the time needed to establish an initial, feasible QoS policy solution VoIP LLQ Provisioning Provisions LLQ for the VoIP bearer and bandwidth 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

31. © 2006 Cisco Systems, Inc. All rights reserved. Cisco AutoQoS Features in a LAN FeatureBenefit 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 SupportEnables NBAR for different traffic types

32. © 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.

33. © 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.

34. © 2006 Cisco Systems, Inc. All rights reserved. Cisco AutoQoS Example (Cont.)  interface Serial1/3  ip cef  bandwidth 1540  ip address 10.10.100.1 255.255.255.0  auto qos voip IP CEF and Bandwidth AutoQoS for VoIP Traffic Recognized by NBAR

35. © 2006 Cisco Systems, Inc. All rights reserved. Cisco Security Device Manager (SDM)

36. © 2006 Cisco Systems, Inc. All rights reserved. Steps 1 to 4: Creating a QoS Policy 1. 2. 3. 4.

37. © 2006 Cisco Systems, Inc. All rights reserved. Step 5: Launching the QoS Wizard

38. © 2006 Cisco Systems, Inc. All rights reserved. Step 6: Selecting the Interface

39. © 2006 Cisco Systems, Inc. All rights reserved. Step 7: Generating a QoS Policy

40. © 2006 Cisco Systems, Inc. All rights reserved. Reviewing the QoS Configuration

41. © 2006 Cisco Systems, Inc. All rights reserved. Completing the Configuration: Command Delivery Status

42. © 2006 Cisco Systems, Inc. All rights reserved. Monitoring QoS Status 1. 2. A B

43. © 2006 Cisco Systems, Inc. All rights reserved. Comparing QoS Implementation Methods Legacy CLIMQC Cisco AutoQoS Cisco SDM QoS Wizard Ease of usePoor Moderately easy Simple Ability to fine-tune AcceptableVery goodLimited Time to implement LongestAverageShortestShort ModularityPoorExcellent Very good

44. © 2006 Cisco Systems, Inc. All rights reserved. Network-Based Application Recognition (NBAR) NBAR is a new classification engine in Cisco IOS ® Software that can recognize a wide variety of applications Including Web-based applications and client/server applications that dynamically assign TCP or User Datagram Protocol (UDP) port numbers After the application is recognized, the network can invoke specific services for that particular application. NBAR currently works with quality-of-service (QoS) features to help ensure that the network bandwidth is best used to fulfil your business objectives.

45. © 2006 Cisco Systems, Inc. All rights reserved. Why NBAR is used Today's applications require high performance to help ensure competitiveness in an increasingly fast-paced business environment. The network can provide a variety of services to help ensure that your mission-critical applications receive the bandwidth they need to provide this performance. The difficulty is that today's Internet-based and client-server applications make it difficult for the network to identify and provide the proper level of control you need. NBAR solves this problem by adding intelligent network classification to your infrastructure.

46. © 2006 Cisco Systems, Inc. All rights reserved. NBAR fits into the Content Networking framework NBAR provides intelligent network classification that can be used to determine which services the network should provide. NBAR currently works with QoS features so that one can provide differentiated classes of service (CoSs) to different applications.

47. © 2006 Cisco Systems, Inc. All rights reserved. Advantages of NBAR Help Ensure Performance for Mission-Critical Applications Reduce WAN Expenses Manage Web Response Improve VPN Performance Improve Multiservice Performance