WHITE PAPER KVM SWITCH SOLUTIONS A guide to evaluating KVM Switches from Network Technologies Inc
INTRODUCTION Network Technologies Inc (NTI) recognizes that advances in computer technology, and the growing importance of the Internet in commercial transactions, have resulted in computer networks becoming more critical to businesses than ever before. Businesses today have increasing demands for space, equipment, and productive use of network administration personnel. Customers need a method to control multiple computers efficiently.
TABLE OF CONTENTS Simply Put ______________________________________________________________________________ 1 What is a KVM Switch? _________________________________________________________________________ 1 KVM Switches in a Network Environment __________________________________________________________ 2 Networks Utilizing a Windows Operating System ______________________________________________________________2 Networks Utilizing a UNIX Operating System_____________________________________________________
TABLE OF FIGURES Figure 1 – Basic KVM switch configuration ___________________________ 1 Figure 2 – Diagram of a Server-Based Network Configuration_____________ 2 Figure 3 – Addition of KVM Switches to a Server-Based Network _________ 2 Figure 4 – Reconfigured server setup with three KVM switch controls ______ 3 Figure 5 – Energy Savings _________________________________________ 4 Figure 6 – KVM Switch used in a Cascade Application __________________ 7 Figure 7A – Cat5 KVM Extender Application _____________
CHAPTER 1 SIMPLY PUT 1 SIMPLY PUT WHAT IS A KVM SWITCH? KVM stands for: Keyboard – Video – Mouse. The primary purpose of a KVM switch is to control more than one computer with ONE keyboard, ONE mouse and ONE monitor (also known as a control console). This is achieved with no special software or hardware modifications to the attached computers. Control of the computer at all stages of operation is achieved by utilizing the keyboard, video and mouse ports.
CHAPTER 1 • • • • SIMPLY PUT A lab manager wants to be able to consolidate control of his lab computers and eliminate many keyboards, monitors and mice where space is at a premium. A manufacturer wants to allow workers on the shop floor and loading dock to conveniently control computers located in a server room, while protecting the computers from theft and harsh environmental conditions.
CHAPTER 1 • • • • SIMPLY PUT Direct access to the host console port. There are some privileges that the console retains which cannot be accessed from another workstation. Figure 3 illustrates a modification of the application in Figure 2. Here, the KVM switches allow the user to control any workstation connected to the switch with full privileges. Speed of display.
CHAPTER 1 SIMPLY PUT translates directly into utility cost savings. The elimination of the heat generated by extra monitors also saves HVAC expenses. • Increasing user productivity is achieved several ways: 1) A KVM switch eliminates user time spent traveling from one control location to another. Instead, the user has the advantage of quickly switching between computers from ONE keyboard, ONE monitor and ONE mouse (or control station).
CHAPTER 1 • SIMPLY PUT designed to translate (seamlessly emulate) all variations of the different devices, including specialized devices such as the Microsoft Intellimouse®. Video switching is more complicated. KVM switches, unlike video cards or monitors, do not have a hard resolution limit that prevents them from handling anything higher than some particular resolution and refresh rate. The switch simply sees an analog signal and passes it through.
CHAPTER 1 • SIMPLY PUT The ability to extend control over a distance, as discussed in the “Flexibility” section above, can be used to place computers in a physically secure environment without sacrificing control. Computers can be located in a limited-access, temperature-controlled server room, while the KVM switch allows the computers to be conveniently controlled from the shop floor, loading dock, etc.
CHAPTER 1 SIMPLY PUT Cascading KVM switches provides a cost-effective method to expand KVM control as an application grows. In such an application, a second KVM switch (a slave) is connected directly to the first KVM switch (a master). In essence, this creates a larger capacity KVM switch. Cascading saves up-front costs because the user need only buy a KVM switch with the capacity currently needed. They do not need to guess at future needs because they can “grow” the KVM switch application as needs grow.
CHAPTER 1 SIMPLY PUT Multiple Platform Control Our Universal KVM switch allows one user to control up to 32 PC, Sun or Mac computers (or 152 computers with cascading) with just one keyboard, mouse and monitor. This switch allows for expansion of the network that is not limited to a particular platform. Using a multiple platform switch as the master in a cascaded application does have one limitation, in that each slave unit is “uni-platform,” as seen in Figure 6.
CHAPTER 1 SIMPLY PUT Control Options A variety of control methods is available for the NTI KVM switch line as standard or optional equipment. Below is a brief description of each. Liquid Crystal Display (LCD) provides a method to select and control attached computers by name from the front of the KVM switch itself. On Screen Display (OSD) allows users to utilize the keyboard or mouse to operate the KVM switch from menus superimposed onto the user’s monitor.
CHAPTER 1 SIMPLY PUT unit connected to the keyboard, monitor and mouse (or just the monitor in the Video Only model). The Local and Remote units are interconnected with Cat5 cable through their RJ-45 connectors. Figure 7A – Cat5 KVM Extender Application. Figure 7B – Cat5 Video Only Extender Application. Crisp and clear 1280x1024 video resolution is supported. Automatic video equalization control compensates for image quality loss over long cables.
CHAPTER 1 SIMPLY PUT Expansion Flexibility The Switch Expansion Unit (SEU), formerly known as the Multiplexor Box, combines up to 16 of NTI’s switches to create a total capacity of eight users and 512 computers – all with true matrix switching. An application of matrix switching with the SEU is illustrated in Figure 8. All users can individually command or simultaneously share control of up to 512 PC, SUN or MAC computers without interfering with each other. Switches can be added as an operation grows.
CHAPTER 1 • SIMPLY PUT An alternate solution, if each graphic designer needs to be able to control all of the department computers, would be a matrix KVM switch attached to all three PCs and all three Macs, with three user control stations (keyboard, monitor and mouse). One application would provide all of the necessary control.
CHAPTER 1 SIMPLY PUT but Windows does not. The entire GUI would be captured and sent over the Internet via TCP protocol. This requires higher bandwidth than terminal emulation. Currently available KVM technology utilizing this protocol does not produce smooth mouse control for the user. Those considering this technology must also consider the major security issues involved in this protocol.
CHAPTER 1 SIMPLY PUT MESSAGE BOARD The NTIforum is the only Message Board solely dedicated to KVM solutions. The Message Board provides a resource for users to discuss KVM applications with both other users and the NTI sales and technical staff who moderate the discussions. Users can learn about KVM product applications, ask questions, discuss solutions, suggest new products or features to meet their needs, or search archives for information on KVM solutions.
CHAPTER 2 TECHNICALLY SPEAKING 2 TECHNICALLY SPEAKING KVM Switch construction differs from manufacturer to manufacturer, as does the engineering of switch products. There are differences in the processor configuration, video board engineering, and keyboard and mouse recognition and connectors. Different manufacturers have different On Screen Display (OSD) software configurations. Each manufacturer has their own way to present control/switching methods.
CHAPTER 2 TECHNICALLY SPEAKING Shared Processor Shared Processor electronic KVM switches utilize one processor to communicate with all attached computers, and so are generally less dependable than those with dedicated processors. Since computers require constant contact with the connected keyboard and mouse, switches with shared processors may freeze or go into an error mode.
CHAPTER 2 TECHNICALLY SPEAKING . Benefits • Continuous, fault-free operation. A 1:1 microprocessor to computer ratio is more efficient in processing data and provides the most reliable performance. Each computer connected to the dedicated processor KVM switch receives all the data required for each computer to constantly recognize the keyboard and mouse. Each processor “talks” to only one computer, thus eliminating errors, freezing, or other problems that can occur in the shared processor configuration.
CHAPTER 2 TECHNICALLY SPEAKING when the user presses a key for On Screen Display commands. Some processors can even update the NumLock, Scroll Lock, and Caps Lock status lights on the keyboard for the currently active computer. Video, such as the multiscan monitor. Most switches support a scan function, which causes the switch to sequentially and incrementally display the video from each connected computer.
CHAPTER 2 TECHNICALLY SPEAKING Table 1: Keyboard Equivalency Translation Sun PS/2 101 Win95 AppleExt L-Control L-Control L-Control L-Control L-Alt L-Alt L-Alt L-Opt Compose R-Control R-Control R-Control Alt-Graph R-Alt R-alt/Aplcn R-Opt Meta SB+Alt Logo Cmnd Power SB+RT Arrow SB+RT Arrow Power SB = Space Bar L and R = Left and right keys when two keys are marked the same on a keyboard Sun keyboard Sun keyboards have 14 extra keys not found on PS/2 101, Win95, and Apple Extende
CHAPTER 2 TECHNICALLY SPEAKING Since PCs were developed before mouse technology, PC mice standards were developed ad hoc, free-for-all and manufacturers developed three types of mice: 1) bus, which is archaic and now rare, 2) serial, and 3) PS/2, which IBM developed. • The PC operating system must contain the appropriate driver to recognize the mouse signals. If the computer does not contain the right driver, it cannot recognize the mouse.
CHAPTER 2 TECHNICALLY SPEAKING is through cables, the cables play the most important role. Poor quality cables can reduce the distance good video can travel. When a KVM switch is added to the equation, degradation of video quality is almost inevitable, especially because few switch manufacturers are willing to take the costly and painstaking measures needed to keep the video signal in optimal condition.
CHAPTER 2 TECHNICALLY SPEAKING Time Domain Reflectometry NTI also tests long video cables using time domain reflectometry (TDR) to ensure signal quality over long cables (over 250 feet). TDR measures reflection time to avoid offsets. If the signal reflection is too great, the signal quality degrades as it travels along the cable. TDR ensures that the signal R, G, and B will be within ¼ pixel of each other.
CHAPTER 2 TECHNICALLY SPEAKING Figure 12 – Front Panel Push Buttons On some NTI models, pressing the CPU Select button lets the user cycle through three modes of operation: SCAN, BROADCAST and COMMAND. The user simply releases the button when the console indicates the desired mode.
CHAPTER 2 TECHNICALLY SPEAKING NTI’s OSD lets you perform the following functions by keyboard and mouse control or front panel control: • Name or rename each connected computer. • “Select” a particular computer. • Search for a particular computer connected to the KVM switch – this is particularly helpful when users connect many computers to the KVM switch application.
CHAPTER 2 TECHNICALLY SPEAKING Multiple User / Multiple Platform KVM Switches The dedicated processors in NTI’s Modular Matrix multiple user/multiple platform KVM switches ensure reliable performance at all times. Each port has its own processor that emulates the keyboard and mouse for the connected computer. This means that even PCs will not crash because the computer will always “recognize” the attached mouse and keyboard, even when the switch activates another computer.
CHAPTER 2 TECHNICALLY SPEAKING Each unused communication port requires a terminator, available from NTI. The student computers connect to a unit with connectors for the keyboard, mouse and video, as well as two communication ports and two video ports. Up to four computers are chained through the communication and video ports to the central unit. The last student unit on the chain requires a terminator on the unused communication and video ports. NTI has these terminators available upon request.
CHAPTER 2 TECHNICALLY SPEAKING Presentation Applications Another interesting use of KVM switches is for presentations that use data from several computer sources to one or more monitors. NTI’s Video Matrix Switch allows up to 32 video sources to output to any or all of up to eight monitors. This unit, which NTI builds to order, supports either 100 or 200MHz bandwidths and resolutions through to 1900x1200 with no degradation.
APPENDIX A The following illustrations and charts provide pin-out designations for the different types of keyboard, mouse and video connectors compatible with NTI’s KVM switch product line. The Cable Distance Guide lays out the maximum distance for each cable type and bandwidth to achieve optimal performance from your cables.
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GLOSSARY active switch An electronic switch in which one or more microprocessors communicate with the attached computers; an electronic KVM switch. ASCII Abbreviation of American Standard Code for Information Interchange – a standard language for the transmission of information. attenuation Signal loss; the reduction of signal amplitude. authorized access A feature of OSD that allows a network administrator to restrict access to particular computers to particular control stations and/or users.
electronic KVM switch A KVM switch which utilizes one or more microprocessors to communicate with the attached computer(s); an active switch. GUI Abbreviation of Graphical User Interface – a program interface utilizing the computer’s graphics capabilities (such as icons and drop-down menus) to make a program easier to use, as opposed to utilizing only keyboard commands.
mechanical KVM switch A KVM switch which does not utilize microprocessors to communicate with the attached computers; a passive switch. microprocessor A single-chip computer element that contains the control unit, central processing circuitry and arithmetic and logic functions and is suitable foruse as the central processing unit of a microcomputer or a dedicated automatic control system. (Source: Illustrated Dictionary of Electronics, 4th Ed., Turner and Gibilisco).
shared processors A microprocessor configuration used in a KVM switch in which one microprocessor is dedicated to communication with more than one attached computer, as opposed to a dedicated processor configuration in which one microprocessor handles communication for only one computer. slave switch A term used in cascade applications.
COPYRIGHT Copyright: Copyright © 2002 by Network Technologies Inc, all rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written consent of Network Technologies Inc, 1275 Danner Drive, Aurora, Ohio 44202. For more information, please contact Network Technologies Inc at (800) 742-8324 (800-RGB-TECH) or (330) 562-7070. 1.800.RGB.TECH (800.
