Using LiveAction Software for Successful VoIP Deployments How to quickly and accurately deploy QoS for VoIP networks

Transcription

1 LiveAction Application Note Using LiveAction Software for Successful VoIP Deployments How to quickly and accurately deploy QoS for VoIP networks September

2 Table of Contents 1. Introduction What is Quality of Service (QoS)? The Stages of Deploying QoS Using LiveAction for a Successful QoS Implementation... 4 Base-Lining Your Network... 5 Defining and Deploying QoS Policies Ongoing Monitoring and Analysis Conclusion... 19

3 1. Introduction When deploying VoIP services, implementation of QoS will improve the end user experience and dramatically increase the long-term success of your project. Quality of Service (QoS) will ensure that delay and loss sensitive voice traffic will receive the proper prioritization and queuing required. LiveAction software from ActionPacked! Networks arms IT departments with a complete solution that enables engineers of all skill levels to efficiently and confidently deploy QoS for interactive services. LiveAction's all-in-one capability supports QoS deployment through the entire workflow of analysis, configuration, testing and tuning. Unlike monitoring-only tools on the market, LiveAction s built-in expert capability lets you build and adjust policies graphically, test and analyze them in the lab, and then deploy them to multiple devices with a single click. Hundreds of device rules and Cisco best practices have been built into the GUI to enable you get changes right the first time. Networkwide traffic visualization and detailed QoS statistics lets you quickly understand how your policies are working and what adjustments need to be made. 1

4 2. What is Quality of Service (QoS)? All networks and the devices within those networks, have limits on the speed and amount of traffic that can flow through them. With packet and frame switched networks, this means at times of congestion, data must be delayed or dropped. Quality of Service management is the collection of mechanisms that control how traffic is prioritized and handled during these times. QoS can be thought of as the entire process of selectively reducing the traffic on a network to the level it can carry. For VoIP deployments, QoS will help ensure that VoIP packets receive the proper priority levels and performance that they require. This application note assumes that users have a working understanding of QoS and Cisco s MQC. For an overview of QoS technologies and how to plan your QoS project, please consult ActionPacked! Networks white paper on deploying QoS, available via the ActionPacked! website. 2

5 3. The Stages of Deploying QoS Defining and deploying QoS can be a daunting task for any IT department, even those with highly skilled engineers on staff. In order to be successful and make the process as manageable as possible, it should be broken up into discrete sequential stages that can serve as milestones for the project. A typical implementation would follow these stages: 1. Project planning and buy-in 2. Investigation and design 3. Experimentation 4. Iterative deployment cycle 5. Ongoing monitoring and analysis LiveAction software is instrumental in accelerating activities in Steps 2-5. This includes multiple steps of the Investigation and Design phase that includes: Base-lining the network Selecting a QoS model Defining QoS policies When deploying QoS you will first experiment on your test network, and when satisfied with the results you can then begin deployment on your production network. Once QoS is fully deployed you will need to perform ongoing monitoring and analysis to determine if any changes need to be made. 3

6 4. Using LiveAction for a Successful QoS Implementation For a successful QoS deployment, the proper set of tools can go a long way towards minimizing frustrations and speeding up the deployment. Implementing QoS requires a wide range of functions from monitoring and analysis to configuration and test traffic generation and analysis. ActionPacked! Networks LiveAction software combines many of these functions into a cohesive, consistent and easy to manage and learn framework. It helps ensure the highest accuracy of monitored data and implemented policies. It also eliminates time spent configuring and learning new tools so it can be better spent actually implementing QoS. Some of the benefits of LiveAction include: Correlating multiple functions and information within a single system view for better network understanding, accuracy, and ease of use Providing the means to make configuration changes directly and then immediately see the feedback from those changes Straightforward installation that doesn t require additional specialized database software and training The following table summarizes functions that you will need for your QoS deployment: Function Use LiveAction Features Traffic monitoring and analysis QoS monitoring and analysis QoS design and configuration Synthetic traffic generation and analysis Initial base-lining and ongoing monitoring of traffic levels. Troubleshooting of any problems encountered QoS policy validation and ongoing monitoring Assist in defining QoS policies and actual configuration of the network devices Traffic generation and analysis for measuring the impact of QoS policies in a controlled manner Traffic filtering by IP address, application, DSCP, etc. Long-term recording, playback and reporting End-to-end traffic path visibility for network understanding Real-time updating for immediate feedback when troubleshooting Support for network flow monitoring, including NetFlow, Sflow or J- Flow Support for QoS MIB monitoring such as Cisco CBQoS and NBAR MIBs Detailed monitoring by class, class drops, application, etc. Historical reporting of QoS performance Wizards and templates for easy policy creation Rules checking and references to ensure error free changes Intelligent configuration that parses existing router policies and adjusts changes as needed Load and save policies Push out policies to multiple devices Ability to leverage built-in Cisco IP SLA technology Graphically generate different types of traffic and analyze performance in summary and detailed formats Combining the entire workflow of analysis, configuration, testing, and tuning into an all-in-one solution that supports QoS deployment can greatly improve the efficiency and quality of the work performed. Using LiveAction s built-in expert capability to build and adjust policies graphically while viewing network-wide traffic visualization and detailed QoS statistics enables a quicker understanding of how policies are working and what adjustments need to be made. This application note illustrates the use of LiveAction to set up QoS to support VoIP on a branch office and HQ network. 4

7 Branch office connected through the WAN to the HQ and its data center and VoIP In this screen shot of LiveAction we are focused on a branch office on the left that is connected through the WAN to the HQ site on the right. The HQ data center houses centralized media and VoIP servers. The network path on the top runs through a WAN and is where the majority of network traffic flows. This path is a relatively low speed 1 Mbs Ethernet service link. Base-Lining Your Network The early stages of QoS deployment involve gathering as much information as possible about the applications on your network and the ability of your network to support those applications. This information will be used to identify and troubleshoot issues, design QoS policies and possibly upgrade your network if your analysis deems that necessary. LiveAction provides a number of capabilities for monitoring and analysis of Cisco devices: NetFlow for traffic visualizations, monitoring and reporting QoS monitoring and reporting using CBQoS and NBAR MIBs IP SLA results monitoring and graphing SNMP MIB polling and reporting of CPU and memory utilization and interface status LiveAction supports two types of traffic flow visibility at the system, device and interface levels that can be leveraged during the initial base-lining and investigation: Real-time interactively observe, understand, identify and troubleshoot network issues Historical investigate historical performance and run reports identifying top talkers, top protocols and more Viewing network-wide traffic flows using LiveAction s topology screen 5

8 The first place to start is with a system-wide view of your network and the traffic flowing across it. LiveAction s powerful visualizations enable you to spot trouble spots on your network such as DSCP re-marking issues, miss-routed traffic, unauthorized traffic and more. Use LiveAction s protocol filtering and flow color-coding to visualize your traffic. DSCP color-coding quickly identifies remarking issues Applying Filtering to Visualize the Network Flows Zero-in on the traffic you are looking for using LiveAction s built-in filters or build your own based on protocol, IP addresses, DSCP, etc. Creating custom filters 6

9 When investigating performance or trouble-shooting, you can go to an individual device view and literally see the flows in real-time as they transit the router. Since the flows are also displayed in tabular view you can sort on columns to identify top talkers and top protocols. The device view gives you flows in table and graphical formats. Sort traffic to view your top talkers and top applications Playback LiveAction s historical NetFlow data A network administrator can analyze historical voice traffic using LiveAction s full suite of flow reporting. The general health of your devices can be determined by monitoring the system tree view of your routers. From this screen you can get a quick summary of CPU and memory utilization problems as well as any packets drops (which may be acceptable if you have QoS policies on those interfaces). Here you can view a quick summary of your CPU and memory utilization green is good, yellow requires investigation and red is critical. Monitor device health in the system tree view 7

10 To collect more data about the quality of your network you can take advantage of LiveAction s IP SLA capability to generate and analyze synthetic traffic. This will also be a useful proactive monitoring tool once you fully deploy VoIP and QoS. Create traffic to evaluate jitter and measure MOS and lost packets. You can choose from a number of simulated codecs and customizable parameters. Create realistic VoIP traffic to monitor network health Use LiveAction s IP SLA topology view to visualize tests that you have running between your branch office and HQ WAN routers. LiveAction s IP SLA topology view let s you visualize the tests you have running in your network and their status. LiveAction System view lets you see the active IP SLA tests 8

11 Then you can view results in graphical or tabular formats. Detailed results will give you jitter, packet loss and MOS results. Viewing the results of the IP SLA tests LiveAction s QoS monitoring capability can be leveraged during the base-lining phase. If you already have QoS policies in place, or by enabling Cisco s NBAR (network-based application recognition) capability, you can get detailed per-application and class rate and drop information. Viewing real-time QoS results before and after the policies are applied Now that you have gathered sufficient information about the current health and performance of your network, it s time to design your policies. 9

12 Defining and Deploying QoS Policies Designing QoS policies and configuring them on routers can be a time-consuming, complex, and intimidating process that requires trained engineers. This process can be greatly simplified with LiveAction s built-in expert capability in the form of GUI wizards, templates and interactive screens for designing, deploying and adjusting QoS policies. Some of the key design and configuration features include: QoS templates and wizards based on best practices and QoS models such as Cisco s 11, 8, 5 and 3 class models Intelligent policy configuration that resolves conflicts with existing device settings Point-and-click NBAR classification policy creation Drag and drop hierarchical policy creation and graphical editing Graphical ACL editor Point and click control of classification, marking, queuing, policing, shaping, compression and WRED settings Built-in rules checking and reference information Before making any changes to your QoS policies it is good practice to snapshot them in case you need to return to a known good configuration. LiveAction has a number of snapshot options in the Manage QoS window. The choice of QoS model will depend on the complexity of your network and the traffic running on it. The more unpredictable your traffic patterns and the greater number of sensitive applications like VoIP, video teleconferencing and mission critical ERP systems will require a greater number of classes. For our relatively simple network we will go with a 5- class model. LiveAction contains these built-in templates that can be access with the QoS policy wizard. In the first step we will create a NBAR matching and class marking protocol at our ingress LAN interface. Then we will incorporate the queuing and other necessary functions at our WAN interface where it is most critical. Launch the policy wizard from the QoS menu and choose the advanced option: Starting the QoS template wizard 10

13 Creating a QoS policy using LiveAction s template wizard Choose the 5-class template with application matching and marking. Choosing a policy form the list of available templates The applications and classifications have been pre-defined but they can be expanded and customized later. 11

14 Now that the policy is saved to the router we can apply it to the appropriate interface. From the Manage QoS window, choose the interfaces tab, select the apply to interface button, choose the appropriate policy and interface. If you have more than one interface you were rolling the policy out to, you can select them all at this step. Applying the policy to selected interfaces With this new policy applied to the ingress interface we can adjust the settings or move onto creating our WAN policy. To create our WAN policy we ll re-run the QoS wizard and use another template. The WAN policy will be a hierarchical policy because we need to shape-down our LAN Ethernet traffic to the appropriate WAN link rate. Let s choose our child policy first and we can use the shaping option in the wizard. Because our traffic has already been marked, we will choose a simple match template. Choosing a policy from the available templates Setting a traffic shaping limit to create a hierarchical policy 12

15 We re fortunate to have a relatively high-speed 1 Mbs Ethernet link to our provider, so we set that rate in the shaping bandwidth box. Using this setting will automatically create a hierarchical policy with the rate entered. Returning back to the Manage QoS window you should see the hierarchical WAN shaping policy with a child policy based on the 5-class match template. We now have a hierarchical policy for our LAN/WAN speed mismatch. Viewing the policies in the Manage QoS Settings window Now we can make adjustments to our child policy to achieve the proper queuing and other behaviors that we want. For each of the classes you need to make the appropriate settings that apply to your network. Here are some guidelines to help you choose those settings: Mark packets as close to the source of the traffic as possible. (i.e. the device itself or the LAN switch connected to the device) Recreational or Scavenger traffic should be policed as close to the source as possible to prevent unnecessary bandwidth usage if it exceeds a certain threshold. A majority of the traffic will be classified as default, so enough bandwidth should be provided to support this type of traffic. Real-time traffic should use priority queues and be assigned adequate bandwidth. However, you should limit the overall priority queue to 33% of the available bandwidth to prevent starving other application traffic. The total bandwidth allocation for classes other than default should not exceed 75% of a link's capacity, to account for Layer 2 overhead and Best Effort traffic. 13

16 For our real time traffic we want to choose the priority queue and set the rate value appropriately. Don t forget to set a rate for classdefault if you set something for the Scavenger class. Otherwise, if a Scavenger class has a percentage but the default class does not, the Scavenger class will receive more bandwidth. Adjusting the behavior of individual classes 14

17 If you are dealing with very low speed links (below 768 kbs), you will need to consider serialization delay and the effect that has on high priority voice traffic. LiveAction has the tools for easily applying compression and LFI (link fragmentation and interleaving) to these low speed interfaces. For low-speed serial links you may need to consider LFI. LiveAction s Manage QoS window allows you to make these adjustments easily. Using Link Fragmentation and Interleaving for slow WAN links Now we return back to the Manage QoS screen and apply the policy to the proper interface. Applying the WAN shaping policy to an interface 15

18 We could roll this policy out to multiple routers by using this feature in LiveAction s Manage QoS window: Use the copy policy button to roll your policies out to multiple devices. Rolling out policies to multiple devices Once all of your changes are made you can save them to the device or preview the CLI commands that will be sent by LiveAction. Preview your changes and save them directly to the device. Saving and preview changes to the router 16

19 Ongoing Monitoring and Analysis Now that your policies have been applied you can use LiveAction s traffic flow and QoS monitoring capabilities to immediately gauge the impact of those policies. These are the same techniques used in the base-lining phases reviewed in the previous sections and involve: CBQoS and NBAR MIB support Interface graphs for before and after QoS on input, output or both Statistics by Class and Class Drops and Interface Drops. This information can also be useful when troubleshooting network latency issues resulting from application malfunctions or virus outbreaks. NBAR application statistics Historical graphs with zoom and report generation Here we can immediately see our WAN shaping policy working as it takes our LAN speed interface traffic down to match that of the WAN link. Viewing the WAN shaping policy in action For longer term monitoring you can take advantage of LiveAction s historical results storage and reporting. You can also use LiveAction s IP SLA monitoring and alerting to proactively alert you of problems with voice quality on your key networks paths. Setup IP SLA tests as in the base-lining section: Viewing running IP SLA Jitter tests 17

20 With your tests up and running, go to the Tools menu and Configure Alerts: Use LiveAction s IP SLA operations and alerts to proactively warn you of VoIP performance degradation. Using alerts to proactively warn of network degradation 18

21 5. Conclusion Implementing QoS on a network of any size is a complex and time-consuming process. Implementation requires a diverse skill set that encompasses technical and even political skills, project management expertise, patience, and confidence. Proper planning, technical and project understanding, combined with LiveAction s QoS monitoring and configuration capabilities, will help network managers and engineers deploy and maintain converged QoS-enabled networks with less time, money, and stress. To learn more about LiveAction, and for information to help you deploy and manage QoS, please visit ActionPacked! Networks at: Copyright 2012 ActionPacked! Networks. All rights reserved. ActionPacked!, the ActionPacked! logo and LiveAction are trademarks of ActionPacked! Networks. Other company and product names are the trademarks of their respective companies. ActionPacked! Networks 155 Kapalulu Place, Suite 222 Honolulu, HI