Testing your network at low cost

Last issue, I talked about the need to test new things before introducing them to your network. Today, I want to show you a way to do that in a tiny bit of space at relatively low cost.

The single biggest problem with setting up a test lab is the amount of space all that equipment takes. Even three or four computers can make a small room seem cluttered. But you can simulate dozens of machines using only one or two PCs using VMware's Workstation product (www.vmware.com/).

I've mentioned VMware before (see: " Virtual machines made easier " www.nwfusion.com/newsletters/nt/2001/00932438.html) but there's a new version (Version 3.1) of VMware Workstation being shipped this week, so it's time to draw your attention to it again.

VMware allows you to run multiple virtual machines (called " guest operating systems " ) on a single hardware installation. It's even possible to have the virtual machines running simultaneously (otherwise it would simply be a variant of a dual-boot machine) - to simulate a network, for example. Many speakers, salespeople and others who do their job " on the road, " but who nonetheless need to demonstrate something running on a network, swear by VMware. VMware running on a well-configured laptop helps them get the job done without the need for a day spent setting up and a half-day tearing down a test network.

VMware Workstation installs on top of an existing operating system (called the " host operating system " ) then virtualizes that operating system so that multiple instances of the guest operating systems can run as if they alone controlled the hardware.

The biggest advance in Version 3.1 is the addition of new host and guest platforms. The Windows operating systems supported as hosts are:

* Windows .Net Web Server Beta 3.

* Windows .Net Standard Server Beta 3.

* Windows .NET Enterprise Server Beta 3.

* Windows XP Professional and Windows XP Home Edition.

* Windows 2000 Professional.

* Windows 2000 Server and Windows 2000 Advanced Server.

* Windows NT Workstation 4.0 and Windows NT Server 4.0.

Other operating systems supported as hosts are: Mandrake Linux 8.0 and 8.1; Red Hat Linux 6.2, 7.0, 7.1 and 7.2; SuSE Linux 7.0, 7.1, 7.2, 7.3 and SLES 7; and Caldera OpenLinux 2.x.

The list of guest operating systems is even longer. In addition to those that can host the system, you can install Windows Me; Windows 98 and Windows 98 SE; Windows 95 (all OSR releases); Windows for Workgroups; Windows 3.1; MS-DOS 6; FreeBSD 3.x, 4.0, 4.1, 4.2, 4.3, 4.4 and 4.5. There's even experimental support for NetWare 6.

This version also introduces language localization (Japanese first, others to follow) better IP networking support (including better support for network address translation, as well as UDP and TCP port forwarding for virtual machines).

A major new feature is called " Repeatable Resume. " This allows you to always resume a virtual machine from a specific point at which you suspended it, over and over. This is useful for a classroom or QA environment, where you want to start your guest operating system with applications already running and system settings tailored to your needs; or, in the event of a catastrophic failure, to restart from the same point, instead of rebooting the virtual machine and reconfiguring. That's very handy in the lab.

You owe it to yourself to check on the feasibility of VMware as at least part of the test bed for your enterprise network.

Dave Kearns is a writer and consultant in Silicon Valley. His most recent book is "Peter Norton's Complete Guide to Networks" published by SAMS. Dave's company, Virtual Quill, provides content services to network vendors: books, manuals, white papers, lectures and seminars, marketing, technical marketing and support documents. Virtual Quill provides "words to sell by..." Find out more at Virtual Quill or by e-mail at info@vquill.com