Cisco’s QoS Device Manager

By Peter J. Welcher
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Dr. Peter J. Welcher (CCIE #1773, CCSI #94014) is a senior consultant with Chesapeake NetCraftsmen, a high-end consulting firm dedicated to quality and knowledge transfer. NetCraftsmen has nine CCIEs, with expertise including high-end routing/switching and design, VoIP, QoS, MPLS, network management, security, IP multicast and other areas. See http://www.netcraftsmen.net/ for more information. Personal home page is http://home.att.net/~p.welcher. New papers will be posted to the NetCraftsmen site. Questions, suggestions for articles, etc. can be sent to [e-mail].
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Let's take a look at Cisco’s QoS Device Manager (QDM) application. This is a free application you download from Cisco. I’ve previously described QDM as “training wheels for QoS.” That’s perhaps dismissing it a little too quickly. The tool looks very useful for light management of QoS as well. It might be useful in both the test lab and for determining or revising your QoS policy.

How To Use QDM
QDM installs in flash on the supported routers and switches. These models include the 1700, 2600, 3600, 7100, 7200, 7600, and VIP-enabled 7500 series of routers. The 6500 switch is also now supported in QDM 2.1. The documentation isn’t clear whether hybrid IOS is required or whether you just run QDM on the MSFC. I haven’t had a chance to test this yet. Anybody that wants to donate a 6500 for my home lab is welcome to contact me at any time.

To access QDM, you do have to enable the built-in IOS Web access. Point your Web browser at the router or switch. There should be a link to QDM, if you installed the download file into flash with the required name. Click on the link. QDM is Java that runs on your PC, accessing the Cisco Class Based MIB (MIB data for Class Based Weighted Fair Queueing, CBWFQ). For more about CBWFQ, see the article New Quality of Service Features in Cisco IOS 12.1, at www.netcraftsmen.net/ welcher/papers/ newqos121.html.

The rest of this article is a sample of what Cisco QDM can do. One reason for doing so is that QDM has little documentation, so there’s no easy way for you to look at a PDF documentation file to see what QDM can do. That might tend to discourage people from actually using it, since it takes work and there’s no immediately apparent value to expending the effort.

This article is heavy on screen captures. Note how easy QDM is to use. Yes, it is a limited tool focused on QoS, so the user interface has limited options. There are some CBWFQ QoS features not supported by QDM, documented in the Release Notes. Among them, applying a CBWFQ policy via sub-interface or FR traffic shaping is not currently supported. Older QoS techniques such as Committed Access Rate (CAR) are also not supported.