Cisco QoS Device Manager

Cisco QoS Device Manager

Q & A

QoS Device Manager
Release 2.0

Q. What is Cisco QoS Device Manager?

A. Cisco QoS Device Manager (QDM) is a Web-based network management application that provides an easy-to-use graphical user interface for configuring and monitoring advanced IP-based quality of service (QoS) capabilities within Cisco routers. With QDM, network managers can configure and monitor a Cisco router to manage traffic congestion so that the performance of critical network applications is protected and not adversely affected by other, less critical, network traffic. As a result, QDM helps network managers maintain the end-to-end performance of mission-critical application traffic on the network.

Q. Which Cisco customers benefit from the use of QDM?

A. QDM will provide value to customers that intend to deploy Cisco routers to support an IP-based QoS network environment. QDM is especially suited for customers that are configuring QoS features in their network for the first time, and who need an easy-to-use tool to help configure and monitor QoS features in the critical router devices in their networks. Such critical routers are typically positioned between the LAN and the WAN, which is a critical point of congestion in most networks. Using QDM, the network manager can quickly and easily configure QoS features, and immediately observe how this QoS configuration affects the pattern of network traffic through the router.

Q. What are QDM's primary functions?

A. QDM has the following four primary functions:

  • Application and protocol discovery for preexisting network traffic patterns (for example, baselining)

  • Definition and configuration of traffic classes based on the applications and protocols discovered

  • Configuration of QoS enforcement mechanisms to be applied to the traffic classes Monitoring of QoS performance after QoS configuration has been deployed.

Q. What are the primary benefits of QDM

A. QDM provides the ability to both configure and monitor QoS features on a Cisco router from a simple, Web-based interface. Furthermore, QDM delivers this functionality within a Web-based architecture that requires no client or server setup. Without QDM, it is not possible to easily monitor QoS device-level statistics, such as traffic rate per QoS class or packet drop rate per QoS class. Furthermore, without QDM, it is much more complicated to configure QoS classes and enforcement mechanisms on the router because it requires detailed knowledge of the Cisco IOS® Software commands related to QoS.

Q. How long has Cisco offered QDM?

A. The first release of QDM by Cisco was in April 2000 and was referred to as QDM 1.0. Subsequently, Cisco released QDM 1.1 in September 2000. Most recently, QDM 2.0 was released in January 2001.

Q. What major new features does QDM 2.0 provide?

A. The most important new feature for QDM 2.0 is that it supports a broader range of Cisco products. QDM 1.1 and 1.1 provided support only for the Cisco 7000 series of routers. In addition to Cisco 7000 series routers, QDM 2.0 also supports the Cisco 2600 and 3600 Family Routers. QDM 2.0 also supports the following new features:

  • Creation and Management of basic access control lists (ACLs) to be used as part of a QoS traffic class definition

  • Configuration of QoS enforcement over virtual private networks (VPNs)

  • Enhanced monitoring and reporting features, such as data export and HTML bookmarks to specific graphs

  • Support for Web browsers that run on Windows 2000 and Linux operating systems

  • Additional classification and marking features, such as class match on IP RTP value, and marking MPLS experimental value

Q. What versions of Cisco IOS Software does QDM 2.0 support?

A. QDM 2.0 supports both the T and the E trains of IOS: Under the T train, IOS release 12.1(5)T is supported by QDM; Under the E train, IOS release 12.1(E) and greater is supported by QDM.

Q. Why does QDM 2.0 require Cisco IOS 12.1(5)T or 12.1(E) to be installed on the router?

A. QDM has been designed to configure and monitor the more advanced QoS features of Cisco IOS, which are only available as part of the Modular QoS command line interface (CLI) framework in IOS Release 12.1(5)T or 12.1(E) and above. The specific QoS features supported by these versions of IOS include Network Based Application Recognition (NBAR), Low Latency Queuing, Weighted Random Early Detection (WRED), Class-Based Weighted Fair Queuing (CBWFQ), policing, and shaping.

Q. Does QDM 2.0 provide end-to-end QoS management?

A. No. End-to-end QoS management is based on the concept of network-wide QoS policies and service levels. QDM does not attempt to configure or enforce network-wide policies, but only configures and monitors congestion in a specific network device. Nevertheless, QDM can provide real improvement to the management of traffic congestion through critical congestion points in the network, such as the LAN/WAN boundary. This congestion management can result in significant improvement in overall network performance.

Q. How can QDM 2.0 benefit an existing end-to-end QoS network?

A. Even in networks where end-to-end QoS policies and service levels have been established, QDM can perform a valuable function. It may not be desirable to use QDM QoS device configuration features when QoS policies are defined across an entire network. However, QDM device-level QoS monitoring capabilities are extremely valuable as a troubleshooting tool. When a specific device has been identified as a congestion point that is disrupting service levels in a network, QDM's traffic monitoring capability can be used as a "drill-down" tool to determine the exact causes of congestion within the device. In fact, the soon-to-be-released Internetwork Performance Monitor (IPM) Version 2.1 will perform hop-by-hop analysis of network performance but will call QDM to monitor specific router devices that are causing performance bottlenecks.

Q. Does QDM 2.0 provide historical reporting as well as real-time monitoring?

A. In addition to providing real-time monitoring of the traffic patterns resulting from the QoS configuration on a router, QDM has a limited capability of providing historical reporting about these traffic patterns. The history period over which QDM provides reporting can range from as recent as the last ten minutes to as far back as the last 5 days. The limitations on the QDM historical reporting are that the historical interval must always start with the most recent sample. It cannot go back further than five days and there is no ability to electronically save historical reports that are created in the present for reference in the future. This historical reporting is available from QDM when the Cisco router is running IOS release 12.1(E) or greater, but not with IOS release 12.1(5)T. Furthermore, the new reporting features of QDM 2.0 provide for the export of traffic pattern monitoring statistics in CSV format, that can be offloaded to a database to be maintained for historical reference.

Q. Which Cisco devices are supported by QDM 2.0?

A. Perhaps the single most important new feature of QDM 2.0 is its ability to support the Cisco 2600/3600 routers. In addition, QDM 2.0 supports all Cisco routers in the Cisco 7XXX product family, including Cisco 7100, 7200 and 7500 devices. It is the intent of Cisco to provide support for additional Cisco devices, such as the Catalyst® 6000 and 4000 switches and the Cisco 1700 routers. Currently QDM is available on the Cisco 71xx and 72xx series routers. It is also available on the Cisco 75xx series routers that use the VIP (Versatile Interface Processor).

Q. What is the architecture of QDM 2.0?

A. QDM is a Web-based Java application that is stored in the flash file system of the router. When the client browser makes a connection to the embedded Web server of the router where the QDM application is stored, the QDM application is uploaded. The client browser must be enabled to support Java and JavaScript in order to be able to load QDM.

Q. What are the benefits of the QDM architecture?

A. The Java-based architecture of QDM simplifies the installation of QDM by leveraging the Web server embedded within Cisco IOS. If QDM exists in the Flash memory of the Cisco router, then any workstation with proper Web browser support can upload and run this application, meaning QDM requires no server installation. This architecture is ideal for network managers that need flexibility to monitor QoS functions from various workstations on their network. Furthermore, because there is no intermediary server, the information that QDM receives from the router is real-time, and direct. Finally, QDM retrieves information from the router, but processes and formats that information at the workstation. As a result, QDM places minimal demand on both the CPU and memory utilization of the Cisco router, leaving them available for handling critical communication processes. Finally, as a device management application, QDM will be launchable from


Q. Can QDM 2.0 configure and monitor any and all Cisco IOS QoS features?

A. No. QDM 2.0 is able to configure only those Cisco IOS QoS features that are available as part of the Modular QoS CLI infrastructure in Cisco IOS.

Q. What are the Cisco IOS QoS features that QDM 2.0 can manage?

A. On the Cisco 71xx and 72xx platforms and the 2600/3600 platforms, QDM 2.0 can configure the following QoS features:

  • Class-Based Weighted Fair Queuing (CBWFQ)

  • Low Latency Queuing (LLQ)

  • Policing

  • Packet marking/coloring

  • Flow-Based Weighted Fair Queuing (FBWFQ)

  • Weighted Random Early Detection (WRED)

  • Classification by several criteria, including NBAR

On the VIP platform of the Cisco 75xx series routers, QDM can manage:


  • LLQ

  • Policing

  • Traffic shaping (dTS)

  • Packet marking/coloring

  • Flow-Based Fair Queuing (FBFQ)

  • WRED

  • Classification by several criteria, except NBAR (not available)

Q. How does QDM make use of the NBAR functionality on the Cisco routers?

A. QDM uses NBAR for two main functions; application and protocol discovery for pre-existing network traffic patterns (for example, baselining) and classification of network traffic into QoS classes. Both of these functions are of fundamental value in QoS device management. NBAR functionality is only available on the Cisco 7100/7200 and 2600/3600 routers, and not on the Cisco 7500.

Q. What products does QDM compete against?

A. The three primary competitors to QDM are Packeteer, Xedia and Check Point. Each of these products offers a slightly different approach to the deployment of QoS functionality. However, these products are similar in that they provide end users with the ability to both configure and monitor QoS functionality from a single, easy-to-use application. The development of QDM was partly a response to the appeal that these products had with customers who were just beginning to deploy QoS features in their networks. QDM, however, is superior to these solutions in several respects. First, QDM allows customers to deploy QoS functionality using features available in the Cisco routers that they already have installed. Second, QDM can quickly configure QoS functionality on any interface of the Cisco router. And finally, because QDM is a no-charge application, the Cisco customer can begin to deploy QoS functionality with zero incremental cost. None of these three competitors can match these claims. QDM has already proven to be the preferred solution by several major Cisco customers.

Q. What is the difference between QDM and QPM?

A. QDM and QPM are complimentary products. QoS Policy Manager (QPM) is a network management application that supports network-wide configuration of QoS functionality in Cisco devices based on policies defined by the user. QPM provides network managers with the ability to set QoS policies on a uniform basis throughout their entire network. QPM is valuable for customers that have already developed an understanding of how to use the QoS mechanisms within Cisco IOS, and are looking for an easier way to administer these mechanisms across all devices in their network. By comparison, QDM does not perform network-wide, multidevice QoS configuration. QDM performs QoS configuration and monitoring on one Cisco router at a time. QDM provides a good starting point for implementing QoS in a network, but QPM will become more valuable as the customer moves toward network-wide configuration of QoS policies. If QPM is used to configure network-wide QoS policies, QDM is still valuable as a device monitoring tool.

Q. Can both QDM and QPM be used to configure the same router?

A. Although it is possible for both QDM and QPM to configure the same router device for QoS functionality, such a practice is highly discouraged. A primary reason for using QPM is to ensure uniformity of QoS policy configurations across all devices in a network. Using QDM to configure a network device that was previously configured by QPM will defeat the uniformity of the QoS policy that QPM intended to establish.

Q. Can QDM recognize the existing Cisco IOS QoS configuration on the device?

A. QDM recognizes and allows modification and monitoring of, and enhancements to, any existing Cisco IOS QoS configuration that has been configured using the Modular QoS CLI found in the 12.1 IOS releases. QoS features that have been configured but are not based on the Modular QoS CLI will not be recognized by QDM.

Q. Will using QDM preclude using the CLI for making QoS changes?

A. No. QDM is designed to allow multiple users to monitor a device. At the same time, it also allows multiple QDM sessions, or a combination of CLI users and QDM users to work together. Configurations created by QDM are understandable by CLI users, and vice versa.

Q. What is the pricing strategy for QDM?

A. Cisco QDM will be offered at no charge. The objective of this pricing strategy is to encourage Cisco customers to try the advanced QoS functionality provided by Cisco IOS on the router devices already installed on their networks.

Q. What are the technical requirements to run QDM?

A. In order for Cisco QDM to function properly, the following system requirements must be met:

  • Router models

    • Cisco 7100/7200 and 7500 (with VIP processors), and Cisco 2600/3600

    • Flash memory with at least 1.5 MB of free space

  • Router operating system

    • Cisco IOS Release 12.1(5)T or 12.1E and above.

  • Workstation operating systems supported

    • Solaris version 2.51 and 2.6

    • Windows NT 4.0 Workstation with Service Pack 5

    • Windows 95 and 98

    • Windows 2000

    • Linux

  • Web browser supported

    • Netscape 4.5.1 and higher

    • Microsoft Internet Explorer 5.0 (Windows clients only)

    • Web browser must have Java and JavaScript enabled