Bandwidth triage for users and applications

Bandwidth can be a precious resource, especially for connections between networks. If all your clients and network applications compete for a limited connection (e.g., an Internet gateway), they—and you—might not be getting the best use of your available bandwidth. Centricity Software’s Centerwise 1.11 lets you manage and prioritize network bandwidth access.

Product Installation
Centerwise installation from the product’s CD-ROM is simple but requires planning. You first need to select a Control Point server, the system in your network from which Centerwise will manage bandwidth. Control Points can be anywhere on your network but preferably in close proximity to the connection you’re managing. To manage access to remote connections and bridges between local or remote networks, complex networks might need multiple Control Points. I installed Centerwise on a Windows 2000 Server machine and configured it as my only Control Point. One NIC connected my server to a simple internal test network, and another NIC connected the server (and the test network) to the Internet. I then used Centerwise to manage client Internet access through this gateway.

You also need to install Centerwise Agents on the client workstations you want to manage. Centerwise supports Win2K, Windows NT, and Windows 9x. To install the Agents, I recommend making the product’s cw.ini file available on a network share, then using installation scripts or Win2K Group Policy to force client installations (the product includes a Windows Installer package for Agent software installation). After the software installs and the client reboots, you need to use the Control Panel Centerwise applet to name each workstation’s Control Point server. To make client installations even easier, you can preset the Control Point server name in the cw.ini file that clients install.

Managing Bandwidth
I first invoked Centerwise’s Control Point Statistics program from the CP system tray icon. This icon is the only location from which you can launch Control Point Statistics. The program displayed how much bandwidth my users and computers were using. Although you can use Windows’ tools to gather similar data, Control Point Statistics collects and presents its data in a format that helps you identify bandwidth hogs and decide how to configure bandwidth. Control Point Statistics identifies machines (and their usernames and IP addresses) with established connections. The UI shows the transmit (Tx, in Figure 1) and receive (Rx, in Figure 1) rates and how these rates translate into allotted amounts of bandwidth. Control Point Statistics also shows the amount of bandwidth that the computer is using the time the program captures the data. You can choose a tabular view or live graphical view, which Figure 1 shows.

You administer the Control Point server and its clients from the Centerwise Administrator program. Unfortunately, you can run this program only from the Control Point server you’re administering, making centralized and remote administration difficult (you can use Win2K Server Terminal Services or a similar program to remotely access Centerwise Administrator). According to the vendor, Centerwise 2.0, which Centricity Software has scheduled to release in late July 2001, offers a Web-based administration interface to permit remote administration.

The cable modem that linked my server to the Internet transmits and receives data at different maximum capacities. The first task for which I used Centerwise Administrator was to input these figures into the program.

Before you can use Centerwise Administrator to regulate bandwidth allocation to your network’s users, you need to populate the Users tab in the UI’s left pane. The Users tab entries take the form username@computer_name@domain_name. Because you can’t use wildcards for any entry element, you can’t manage users and computers independently of one another. This limitation means that you can’t set a computer priority level that regulates that machine’s bandwidth access regardless of who’s logged on, and you also can’t set a user priority level that regulates that user’s bandwidth access no matter where that user logs on. According to the vendor, Centerwise 2.0 policies will follow users from machine to machine.

To assign policies to users and their machines, you select a user from the Users tab in the UI’s left pane, then use the Relative priority slider to assign that user a bandwidth-access priority level from 1 (Low) to 8 (Urgent). You can also create user groups and assign them priority levels. You need to save settings to activate them.

More interesting is Centerwise’s ability to set bandwidth priorities for applications that clients access over the network. This feature lets you restrict the bandwidth available to applications that hog bandwidth and aren’t business-related. Application priorities apply only to those machines on which you’ve installed Agents. To set application priorities, you select applications from Centerwise Administrator’s Applications tab and use the Relative priority slider to assign bandwidth priority levels to the applications. For example, to ensure that your company’s order-entry application has a higher priority than Napster, you can assign Napster the level 1 priority, as Figure 2 shows.

Centricity Software prepopulated the Applications tab’s list with common applications, including many versions of Netscape Navigator and Microsoft Internet Explorer (IE). I used the Tools menu’s Define Applications function to add applications to the list. The Define Applications function needs some refinement, such the addition of a browsing feature. (Currently, you need to type in the executable’s name to add its application to the list—for example, you need to type iexplore to add IE to the list.)

After I set priorities, I opened Control Point Statistics again. The UI’s graphical displays let me verify that Centerwise was managing bandwidth as I had configured it to. I quickly noticed that Centerwise imposes user bandwidth priorities only when a connection is being used to capacity. That is, if you’ve assigned a user the lowest priority but he or she is the only person using a connection, he or she will have access to 100 percent of the connection’s bandwidth.

Centerwise Administrator also lets you manage subnet bandwidth. When you select a user or group to manage, the user or group’s properties, including an IP Subnet Filter section, appear on the right side of the UI. You can use the IP Subnet Filter feature to control traffic between your network’s IP subnets. I used this feature to impose bandwidth priorities to my cable modem’s Internet connection without imposing bandwidth priorities to connections between my LAN’s machines. However, when you define subnet filters, the UI is unclear about which IP address you need to enter. The Administrator’s Guide documentation was disappointingly unhelpful on this point.

You can also use Centerwise Administrator to block access to a specified list of Internet sites. However, to block these sites, the feature blocks DNS resolution of their domain names. Therefore, users can still access sites in the local cache and use IP addresses instead of domain names to access blocked sites.

Additional Considerations
Centerwise’s online Help isn’t Microsoft’s standard HTML Help but is HTML-based. Although this Help format isn’t Web-based, context-sensitive, or searchable, the format is fine for most situations. Centerwise Administrator lets you back up and restore the Control Point database. However, Centerwise makes only one backup at a time and saves that backup only to a specific Centerwise folder subdirectory. Each new backup overwrites the previous backup. More sophistication (e.g., letting you specify where to save the backup) would improve this product feature.

The product’s UIs are also slightly clumsy. Some program windows, such as the log window, aren’t resizable. When you select users and groups from Centerwise Administrator’s UI, the properties area’s subsections (e.g., IP Subnet Filters) should also be resizable. As a result, to use the product I needed to scroll a lot. However, Centricity Software redesigned the UI for the product’s second version.

The Virtual Help Desk is Centerwise’s only UI for the clients on which you’ve installed Agents. When Agents detect certain networking errors, Virtual Help Desk’s pop-up messages report the errors to the user. These messages are somewhat helpful: They’re more verbose but not substantially clearer than the messages Windows might give you. Nevertheless, the Virtual Help Desk is a necessary feature; the pop-up messages also notify users about Centerwise events such as attempts to access a blocked site.

You can activate the product’s logging program from the CP icon in the system tray, but the program doesn’t provide much useful information. The log entries are meaningless to the user: They look more like debug statements for Centerwise programmers than logged program events. My Win2K Server machine’s event log showed no Centerwise events, which is a shame: Many program events, such as bandwidth constraints and client attempts to access blocked sites, are worth reporting.

The product has "version 1" written all over it. The holes in its administration capabilities are frustrating. The Help and documentation gaps make configuration a longer process than necessary. Program developers didn’t plan some features, such as logging and backup, well. Nevertheless, Centerwise’s primary functionality—bandwidth management at the user and application level—is undeniably useful, and the statistical graphs give compelling evidence that this functionality works. At $5000 for a 100-user license, the product isn’t a solution that many companies can casually try. However, the enhancements to the product’s second version make it a more justifiable purchase.

Centerwise 1.11
Contact: Centricity Software * 503-675-1200 or 888-675-3090
Web: http://www.centricitysoftware.com
Price: $5000 for branch office edition (as many as 100 concurrent users); $25,000 for enterprise edition (as many as 500 concurrent users)
Decision Summary:
Pros: Effective primary functionality; helpful graphical displays of bandwidth utilization
Cons: Clumsy UI; no remote administration capabilities; inability to manage computers and users independently of one another; inadequate logging