Advancing the art of KVM switches

Networked keyboard, video and mouse (also known as KVM via IP) is the third major step forward in server operations management. The first step was mounting servers in racks, while analog KVM provided the second step. You can imagine what server farms would look like without these advances.

KVM via IP lets you control servers from a greater distance than analog KVM did. While analog KVM devices and servers typically must be within several feet of each other, KVM via IP extends server control across the breadth of your IP network or even the Internet.

In addition to access over 10/100 Ethernet, you often can use a dial-up connection or Web browser to control your servers. KVM via IP devices help monitor server health, scale better than analog KVM, offer multiuser access and, to an extent, reduce the complexity of the jungle of cables connected to your servers. Because you can daisy-chain KVM via IP devices, they're highly scalable.

KVM via IP devices digitize keyboard, video and mouse signals into compressed and encrypted IP datastreams. The networked KVM data flows to a central unit to which the physical keyboard, monitor and mouse are attached. Unless you have plenty of spare bandwidth on your regular network, putting the KVM devices on their own network segment is a good idea. High-resolution video data, even compressed, can chew up production bandwidth you might not want to allocate to KVM. "Out-of-band" KVM also can provide access to your servers even when routers or other "in-band" network components fail. The central unit may have a serial port to which you connect a modem for remote access, and it may even provide Web-based server management via a browser-based Java applet.

To reveal the current state of the art regarding KVM via IP, we invited vendors to submit their network-based interaction-consolidation devices to our Connecticut lab for evaluation. Avocent sent its DSR2161 and DS

Who we looked at
How we did it

1800 devices along with its DSView software. CCC Network Systems gave us a look at FreeVisionIP Version 3.0. Raritan Computer shipped us a Paragon Matrix UMT442 and a TeleReach KVM Access-over-IP appliance. Rose Electronics sent its UltraMatrix and UltraLink products, while Digital V6 submitted a Kaveman unit.

All units supplied reliable operation, excellent and responsive server control (as long as we didn't use the vendor's browser-based interface) and easy, quick installation. Bandwidth utilization in all cases was reasonably low. It was almost unmeasurable when we used the KVM switches with NetWare servers and less than 5% to 20% in the presence of our Windows- and Solaris-based servers. Utilization was low because the vendors' compression algorithms are high-quality and because we performed typical server administration tasks in our tests instead of trying to stress-test the switches by running, say, Microsoft Flight Simulator. KVM via IP devices are more expensive than their analog counterparts, but server farm administrators who need to control their servers from more than a few feet away will find KVM via IP worthwhile.

Avocent's DS1800 and DSR2161

The DSR1800 is a network-based KVM unit with PS/2, Sun and Universal Serial Bus (USB) server ports. You can connect up to eight servers to each DSR1800; it supported eight concurrent users and worked with video resolutions up to 1,280 by 1,024 pixels in our tests. In contrast, the DSR2161 is a unit intended for PS/2-centric (such as Intel-based) servers. It has 16 server ports, supports one local and two digital concurrent users, and worked with video resolutions up to 1,280 by 1,024 pixels. The DSR2161's thoughtful design uses standard Category 5 cabling to connect servers to the KVM switch, which means you can locate the DSR2161 farther from the servers.

You can connect a physical monitor, keyboard and mouse directly to the DSR2161, and you can use Avocent's IP-based DSView software (a Windows application) to manage your servers over the network. DSView is the only server management interface to the DS1800. In contrast to the TeleReach and Kaveman units, the DSR1800 and DSR2161 don't offer browser-based access. (The company's new AutoView 1000R and AutoView 2000R KVM switches should be available soon. The accompanying AVWorks software offers a browserlike visual interface, with AVWorks acting as the Java-based browser.)

Both units behaved transparently and unobtrusively in the lab. Switching between servers was a breeze. The vendor's DSAuth user authentication software, which stores permissions, passwords, topology and per-device contact information, ensured secure access to our servers.

Raritan's Paragon Matrix and TeleReach

The three components of a Paragon Matrix KVM system are a central Matrix Switching Unit, a User Station to which you attach the physical monitor, keyboard and mouse, and a Computer Interface Module, which connects each server to the Matrix Switching Unit. Each Matrix Switching Unit can connect up to 16 User Stations to up to 64 servers' Computer Interface Modules. Paragon Matrix worked with video resolutions up to 1,600 by 1,200 pixels.

TeleReach, an appliance you attach to a Paragon Matrix system, offers server control for up to four concurrent users via a Web browser or dial-up modem. It worked with resolutions up to 1,280 by 1,024 pixels.

Paragon and TeleReach enforced password-based security on our server accesses, and we could choose from three modes of operation for each server session. These modes are Private, which grants exclusive server access, PublicView, which lets multiple users see the server's screen, and PC-Share, which lets multiple users interact simultaneously with the same server.

Rose Electronics' UltraMatrix and UltraLink

The UltraMatrix is an analog (non-networked) KVM unit that consolidates up to 16 PS/2, Sun or USB server connections while offering up to 16 users concurrent access. It has a modular design that makes expansion painless. UltraLink, which adds an IP link to an UltraMatrix KVM device, worked with resolutions of up to 1,280 by 1,024 pixels and provides server control via Rose Electronics' Windows-based Remote Access Client software. Gaining access to KVM-attached servers through UltraLink and the Remote Access Client is a simple matter of supplying the IP address of an UltraLink device.

UltraLink challenged us to supply a password for each server we accessed, and it coordinated with the Remote Access Client to put video displays from up to four servers on the same monitor. We loved being able to size and move each server's display at will. UltraLink has a serial port for dial-up modem connections that worked without a hitch.

CCC Network Systems' FreeVisionIP

Connected to each server, a FreeVision Extender Mini-transmit device collects servers' keyboard, video and mouse data, and sends the data to a FreeVisionIP switch. The switch in turn connects to a FreeVisionIP server that compresses the data and makes the KVM data available across an IP network. Administrators use CCC Network Systems' Windows-based client software to access FreeVisionIP-managed servers. In tests, FreeVisionIP worked with video resolutions up to 1,024 by 768 pixels for two concurrent users. FreeVisionIP switches have eight or 16 server connections and two IP network ports. (The forthcoming Version 4.0 switch will have four ports.)

The FreeVisionIP server is a rack-mounted Windows NT 4.0-based computer with one 10/100 network adapter and pre-installed FreeVisionIP server software. The FreeVisionIP server interfaces with the incoming video signals via a PCI-based video grabber card.

Digital V6's Kaveman

A Kaveman unit adds IP connectivity and browser-based server access to an existing KVM system. It worked with video resolutions of up to 1,280 by 1,024 pixels and supported up to 10 users in our tests. Following Digital V6's recommendations, we used Internet Explorer 6.0 and Java Runtime Environment 1.4 with Kaveman. Although server keyboard, video and mouse responsiveness was a bit sluggish, Kaveman was otherwise trouble-free and reliable in our tests.

Kaveman wasn't quite as easy to set up and install as the other products, requiring us to reset each server's mouse speed and acceleration for graphical interfaces such as Windows and Solaris.

Placing a special emphasis on security, Kaveman supports x.509 certificates, offers 128- or 56-bit Secure Sockets Layer encryption and can use the RC4 or Data Encryption Standard encryption algorithms. It has what Digital V6 calls a stealth mode, which prevents port scans and other probes by hackers, and a turtle mode, which automatically disables Kaveman when it detects intruders. Resetting turtle mode requires manual intervention at Kaveman's local console. For training and other purposes, multiple users can concurrently connect to the same server.

The future of KVM via IP

After testing these devices, the fourth significant step forward in server operations management will likely be the natural extension of Bluetooth wireless technology to connect servers to a nearby central unit, which could then connect to a physical keyboard, monitor and mouse. A wireless device attached to each server would only need to have keyboard, video and mouse ports for the short cables from the server, along with a radio link with a radius of a few hundred feet. This approach would virtually eliminate the cable jungles that plague many server farms.

Alternatively, for Windows, Solaris, AIX and other operating systems, KVM vendors might opt to write drivers that intercept keyboard, video and mouse data and shunt that data to a central unit via a network interface card in the server. The driver alternative will be less attractive to customers who abhor adding any software to their established corporate standard server configurations. On the other hand, converting KVM data into network data directly inside the server via driver software means that a server would need only one connection to the outside world -- the network cable.

Another suggestion is adding SNMP to KVM devices (FreeVisionIP already supports SNMP). For KVM via IP systems that have a separate out-of-band network segment connection between the servers and the KVM-attached keyboard, monitor and mouse, SNMP doesn't make sense. However, if you send KVM via IP data in-band, across your company's regular network, using Hewlett-Packard's OpenView or other network management system products to handle SNMP alerts from KVM devices could be quite useful.

The KVM via IP enhancements we envision won't appear any time soon. But for nearly every collection of servers -- but especially for server farms with analog KVM devices in close proximity to servers -- KVM via IP eases distance limitations and offers excellent server monitoring and control capabilities.

Nance, a software developer and consultant for 29 years, is the author of Introduction to Networking, 4th Edition and Client/Server LAN Programming. His e-mail address is barryn@erols.com.

Global Test Alliance

Nance is also a member of the Network World Global Test Alliance, a cooperative of the premier reviewers in the network industry, each bringing to bear years of practical experience on every review. For more Test Alliance information, including what it takes to become a member, go to www.nwfusion.com/alliance.

Advancing the art of KVM switches

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