Introducing LXI to your Network Administrator

Transcription

1 Introducing LXI to your Network Administrator May 1, 2013 Edition Notice of Rights/Permissions: All rights reserved. This document is the property of the LXI Consortium and may be reproduced, but unaltered, in whole or in part, provided you retain the LXI copyright on every document page. 1

2 Table of Contents INTRODUCING LXI TO YOUR NETWORK ADMINISTRATOR INTRODUCTION TYPES OF LXI DEVICES LXI PORTS, PROTOCOLS, AND SERVICES LXI DEVICE BEHAVIOR ON THE LAN RECOMMENDED LXI TEST SYSTEM LAN CONFIGURATIONS OPEN SYSTEM CONFIGURATION USING SWITCH ISOLATED SYSTEM CONFIGURATION USING ROUTER ISOLATED SYSTEM CONFIGURATION USING DUAL NETWORK CARDS WIRELESS ROUTER AND BRIDGE CONFIGURATION ACCESSING LXI DEVICES REMOTELY VIA COMPANY INTRANET ACCESSING LXI DEVICES REMOTELY VIA VPN CONNECTIONS LXI DEVICE SECURITY RECOMMENDED STEPS FOR THE NETWORK ADMINISTRATOR APPENDIX A. GLOSSARY OF TERMS

3 1 Introduction Test System Developers and users desire to use LXI Devices (LAN extensions for Instrumentation) to build a test and measurement system which successfully connects to the company LAN. The Network Administrator needs to understand how LXI Devices behave when connected to the company LAN. This document describes how LXI Devices interact with the LAN, so the Network Administrator can maintain LAN security and maximum performance while meeting the requirements of the test and measurement system. Here is a list of typical issues where users need help when connecting LXI Devices to the company LAN: Procedures and requirements for adding new devices to the company LAN Test System performance can be affected by LAN broadcast traffic Recommended LAN Switches and Routers to support LAN throughput needs of LXI Devices Test System may require multi-user access, or it may be desirable to avoid multi-user access Test System Developers often need to monitor Test System operation remotely Updates and backups for the Test System computer should avoid interrupting running tests LXI Devices may require software updates and should not be updated while running tests Test System computer may push test results to a company network Database Server Please Note: adding an LXI Device to the company LAN would involve the same process as adding a computer to the company LAN. LXI Devices are required to act the same. Figure 1.1 Topics covered in this guide. 3

4 The LXI Consortium has written two other documents to help users and Test System Developers: LXI Getting Started Guide and Building LXI-based Test Systems, located on the LXI Consortium Website at GuidesForUsingLXI. These documents will assist them in properly using LXI Devices on the company LAN. However, there are constant references for users to work with the Network Administrator before connecting to the company LAN or using any LAN Device that could compromise network security or performance. 2 Types of LXI Devices LXI is the standard for Test and Measurement Instruments and provides a consistent and predictable behavior for LXI Devices connecting to the LAN. The LXI Consortium formed in 2004 to bring consistency to LAN operation and configuration for LAN-connected instrumentation. As of May 2013, there are over 2000 LXI conformant devices. Just about every instrument type you can imagine has an LXI conformant offering. Here are a few of the instrument types. There are many more from over 35 vendors of LXI Devices. Capacitance Meters Counters Digitizers Digital Multimeters LCR Meters Logic Analyzers Network Analyzers Oscilloscopes Power Meters Power Supplies Signal Sources Sound and Vibration Analyzers Spectrum Analyzers Switches LXI Core Functionality LXI Conformant Devices all provide a base or core behavior when connecting to LAN and requiring various Ports, Protocols, and Services over LAN. They must provide a Home Web page for identification and description, and they must provide a LAN Configuration page for setting IP Address mode, IP Address, Subnet Mask, Gateway access, etc. This is all very similar to the configuration of a typical computer with LAN. LXI Extended Features Optionally, LXI Devices may provide features such as LXI Time Synchronization (IEEE ), LXI Events (peer-to-peer or broadcast), and IPv6 protocol, all of which introduce additional LAN traffic. These Extended Features often require additional LAN Configuration pages on the LXI Device. 4

5 3 LXI Ports, Protocols, and Services LXI conformant devices have a standard set of Ports, Protocols, and Services for LAN operation, but there are also LXI Device-specific Ports, Protocols, and Services. LXI Extended features are optional, and the Home page of the LXI Device lists these extended features, if implemented. Standard LXI Device Ports, Protocols, and Services Protocol/Service Port Base Protocol Notes mdns 5353 UDP/TCP Zero-config protocol for <hostname>.local address resolution; service discovery; Multicast , FF02::FB Http 80 TCP Instrument web pages ICMPv4 ICMP Typically enables echo request/respond for ping ICMPv6 ICMP Optional - Typically enables echo request/respond for ping, also SLAAC for IPv6 addresses, RDDNS Arp Arp Used to confirm address assignments DHCPv4 67/68 UDP/TCP IPv4 address assignment, DNS Server, Dynamic DNS, Gateway DHCPv6 546/547 UDP/TCP Optional IPv6 address assignment, DNSv6 Server, IPv6 Gateway DNS 53 UDP Naming service Telnet 23 TCP Bidirectional interactive textoriented communication. LXI Device-specific Ports, Protocols, and Services Protocol/Service Port Base Protocol Notes HiSLIP 4880 TCP Optional instrument control protocol VXI TCP Builds upon Sun-RPC and port-mapper. Scpi-raw 5025 TCP Optional instrument control protocol Scpi-telnet 5024 TCP Optional instrument control protocol over Telnet LXI-eventsvc 5044 UDP/ TCP Optional LXI Event support for instrument triggering; multicast , FF02::138 Ptp-event 319 UDP/ TCP Optional LXI Profile IEEE 1588 Precision Time Protocol; multicast , FF02::181 Ptp-general 320 UDP/ TCP Optional LXI Profile IEEE 1588 Precision Time Protocol; multicast , FF02::181 5

6 4 LXI Device Behavior on the LAN An LXI Device needs an IP Address just as computers do when connected to the LAN. They support an Automatic or DHCP IP Address mode, and a Static IP Address mode. The behavior of the LXI Device follows very closely the model of a computer connected to the LAN. Automatic or DHCP IP Address Mode When connecting to the LAN, if a DHCP Server is available, an LXI Device acquires its IP Address, Subnet Mask, Gateway, DNS Server, etc. from the DHCP Server If the DHCP Server does not respond, the LXI Device drops into the AutoIP or Link Local Addressing mode. For IPv4, the address range used is x.x, same as the computer. The LXI Device sets its LAN Status to non-fault if successful in acquiring an IP Address Static IP Address Mode LAN Status When connecting to the LAN, the LXI Device broadcasts its desired IP Address. If no other device responds as using that IP Address, the LXI Device formally connects to the LAN. If another LAN Device is using that IP Address, the LXI Device disengages from the LAN and sets its LAN Status to a fault condition. LXI Devices must have a LAN Status indicator that shows the health of the LAN connection. LAN Status indicators must be on the Front Panel of the LXI Device, but they could be LEDs with labels or embedded in the Display menu under a Utility or System key. Figure 4.1 illustrates three examples of LAN Status fault conditions where the LXI Device could not acquire an IP Address. LXI Devices with Displays typically show an IP Address of with the fault indicator. Front Panel with Display LAN Status Fault Front Panel No Display * Front Panel Limited Display Figure 4.1 LAN Status Indicators LAN Reset for LXI Device An LXI Device has a required feature called the LAN Configuration Initialize (LCI or LAN Reset) which defaults to the Automatic IP Address or DHCP mode and restarts its LAN operation. This usually corrects problems associated with a Static IP Address assignment that conflicts with the existing local subnet. The LAN Reset is either a recessed button on the LXI Device or a menu 6

7 entry in the Utility or System menus, as shown in Figure 4.2. You may need a paper clip to access the recessed button. LAN Configuration Figure 4.2 LAN Reset (LCI mechanism) Every LXI Device is required to support a LAN Configuration page accessible from the Home page of the LXI Device. This LAN Configuration page provides a way to configure the LAN settings of the LXI Device. An LXI Device s LAN Configuration is very similar to a computer s LAN Configuration page. Figure 4.3 illustrates the analogous configuration between a computer and LXI Device LAN Configuration pages. Figure 4.3 LAN Configuration 7

8 LAN Discovery LXI Devices must have several features to assist finding their IP Address on the LAN. If the LXI Device has a Front Panel Display, the IP Address may be available from the Display. However, some LXI Devices do not have a display. The LXI Consortium provides the LXI Discovery Tool at GuidesForUsingLXI to find the IP Address of devices meeting the LXI Specification. This tool discovers IP Addresses of LXI Devices visible to the computer s subnet using the mdns and VXI- 11 protocols, which are described further in Section 2 LXI Ports, Protocols, and Services. For more information on LAN discovery, please access the LXI Specification at the following location: The Section LAN Discovery and Identification in the LXI Specification covers the discovery requirements for LXI Devices. The VISA Library (Virtual Instrument Software Architecture) is available from several vendors and may provide an LXI discovery tool. Test System Developers often install VISA on their Test System computer for instrument control. After determining the LXI Device s IP Address from the Front Panel or discovery tool, use a Web browser to access the Home page and the LAN Configuration page. LAN Operation and Performance Most LXI devices support 100Mbit Full Duplex operation, but many support Gigabit LAN. Some LXI Devices require large amounts of data transferred from the computer to set up signals applied to a DUT (Device-Under-Test), while other devices make 1000 s of high-speed measurements for transfer back to the computer as quickly as possible. The majority of instruments interact in short bursts of ASCII or binary representing setup and data. Digitizers and Oscilloscopes are examples of devices that may transfer millions of readings per second, with each reading in a 2 to 8 byte format. However, they typically do not stream data continuously across the LAN. Most test systems involve a sequence of programming steps for connecting test signals through an analog switch between a signal source, the DUT, and the measurement instruments. It is typically a sequential programming model where the computer configures the instruments for each test using short bursts of commands and data. Do this now do that with hundreds of tests that could last for hours. 8

9 5 Recommended LXI Test System LAN Configurations The LXI Consortium members have recommended six LAN Configurations for LXI-based Test Systems. Each of these configurations in the following sections provides a short description, the LAN interconnections, and a list of Benefits and Cautions. The Test System Developer will choose one of these LAN Configurations (or a variation) for their Test System, and they will likely need help from the Network Administrator in the following areas: Help in acquiring IP Addresses from the LAN DHCP Server, if special registration required Permission to connect Routers to the company LAN for private subnet Test System Permission to use and help to configure wireless LAN for LXI Devices Help configuring any required IT access to Test System computer Help setting up remote-login to Test System computer Help scheduling backups and software updates that do not interrupt running tests Help setting up security for LXI Devices using commercial operating systems Figure 5.1 shows an overview of the first four recommended Test System LAN Configurations. The remaining two LAN Configurations are a subset of these and discussed later. Figure 5.1 Summary of recommended Test System LAN Configurations 9

10 5.1 Open System Configuration Using Switch This configuration provides open access of the Test System computer and LXI Devices to all users on the LAN. It permits multiple users to develop tests using the Test System. All LXI Devices acquire an IP Address from the company DHCP Server. Benefits Cautions Test System is accessible by anyone on the LAN Network Users can develop, troubleshoot, and execute tests from their own computer instead of only using the Test System computer Users can monitor activity of LXI Device using a Web browser Network Administrator has complete access to Test System computer for security updates and backup Traffic on LAN Network affects performance of Test System. Active tests may be interrupted by other users accessing the Test System computer or the LXI Devices, including accessing their Web pages Each device in the Test System requires IP Address from company DHCP Server IP Addresses can change with re-configuration of DHCP Server Security updates and backups may affect Test System performance and should be coordinated to times when the Test System is not in use LXI Devices with a commercial operating system like Windows on their embedded computer may also require coordinated updates to avoid interrupting tests 10

11 5.2 Isolated System Configuration Using Router This configuration hides the Test System computer and LXI Devices from the LAN. It isolates the Test System from the LAN to avoid performance degradation or interruption of tests. Only the Router acquires an IP Address from the company DHCP Server. Benefits Cautions Test System and computer are isolated from LAN users and traffic which maintains performance of Test System with no interruption of tests Test System computer can maintain a fixed operating system revision that is not changed automatically by Network Administrator software Single IP Address required from company DHCP Server while computer and LXI Devices receive their IP Address from the built-in DHCP Server of Router Can configure Router to use MAC Address Cloning, enable Ping, and pass port requests to the computer to make it appear still on the LAN. Router configurable to allow remote-login from external users Network Administrator may lose access to Test System without special configuration of Router. Loss of remote-login access by users without special configuration of Router Ethernet port on Router should never be connected to LAN Network The company DHCP Server may not allow Router connected to LAN Network and will not assign IP Address Loss of Domain Name Service (DNS) for using Hostnames on local network 11

12 5.3 Isolated System Configuration Using Dual Network Cards This configuration hides the Test System LXI Devices from the LAN but leaves the computer accessible. Test Developers can remote-login and develop tests, and LXI Devices are not affected by interrupts from LAN traffic. Benefits Cautions LAN Interface NIC #1 of computer connected to LAN Network, so company DHCP Server does not see LXI Devices on NIC #2. Users can remote-login to Test System computer to control LXI Devices Network Administrator has access to computer for security updates and backup LXI Devices isolated from LAN users and broadcast traffic Single IP Address required from DHCP Server for computer. LXI Devices can use static IP Address or AutoIP Address or can run software DHCP Server installed for NIC #2 Loss of Domain Name Service (DNS) for using Hostnames on local network Viruses introduced into LXI Devices can infect computer through NIC #2. Computer must have way of cleaning viruses from NIC #2 subnet Some LXI Devices may need computer support between NIC s, such as Internet Connection Sharing (ICS), to access the Internet through NIC #1. 12

13 5.4 Wireless Router and Bridge Configuration This configuration demonstrates how to overcome environmental hazards, wiring difficulties, or distance limitations while providing a reasonable method to maintain LAN security using wireless communication in combination with Dual NIC interfaces. The Dual NIC provides an extra level of isolation to block wireless access to LAN. Benefits Cautions All the benefits of Isolated System Configuration Using Router Wireless WPA2 security and no Router connection to LAN Network offer good security Remote LXI Device can be located on moving structure, in toxic/hazardous environment, differing ground potentials, at a distance from Test System, etc. Significant cost savings when avoiding long-distance wiring and complexities for the above listed use cases. All the cautions of Isolated System Configuration Using Router Wireless configurations may not be allowed or possible in some environments Wireless connections share bandwidth, which can degrade performance. 13

14 5.5 Accessing LXI Devices Remotely via Company Intranet. This configuration permits users to access equipment at different company sites. Users at one site can develop, troubleshoot, and monitor Test Systems installed at another site, even sites in different parts of the world. Users must know the remote LXI Device IP address in order to access it and may need help in determining these IP addresses. Benefits Cautions An extension of benefits for Open System Configuration Using Switch where users are now at other physical sites within the company intranet All communication exists behind the company Firewall Engineering and Test Development may be on one site and Production at a different site. Developers can monitor and troubleshoot Test System without traveling to remote site. Users need only communicate IP Addresses to each other Training and consulting on complex instrumentation can occur remotely Antenna testing works for this configuration since the Test System signal source can transmit through air with the receiver controlled through intranet at remote site Extension of cautions for Open System Configuration Using Switch Unless a virtual private LAN (VPN) implemented, users at different sites must inform each other of LAN IP Addresses, since the LXI Discovery Tool cannot discover LXI Devices on different subnets LAN performance limited by network interconnect speeds between source and destination 14

15 5.6 Accessing LXI Devices Remotely via VPN Connections This configuration permits a user to access the Test System from anywhere in the world using the Wide Area Network. A user can develop, troubleshoot, and monitor a Test System from outside the company intranet. This is a typical configuration for employees accessing the company LAN while at home or traveling. Benefits An extension of benefits for Open System Configuration Using Switch where a single user can now access the Test System from anywhere VPN (Virtual Private Network) extends the company intranet across the Internet so remote user is virtually on the company LAN. User can access Test System directly from remote computer or can remote-login to Test System computer. Remote-login to Test System computer provides user ability to run test programs at speed of Test System. Provides developers access to Test System while traveling or from home Cautions This configuration requires extensive support from the Network Administrator but is typical with today s workforce working remotely. Running test programs on remote computer could be very slow and cause timeouts and test failures 15

16 6 LXI Device Security Most LXI Devices use an embedded operating system that does not pose a security threat since they do not access or surf the Web. These same devices might support removable USB drives that could potentially infect the LXI Device if the embedded operating system allows running software on that USB device. However, these LXI Devices boot from a fixed, non-infected operating system image, so viruses are temporary. There are some LXI Devices with embedded computers using commercial operating systems requiring virus protection software. These devices would be susceptible to the same security attacks as a company computer, except the devices typically would not be used for or surfing the Web. LXI Devices with these commercial operating systems often ship with Firewall protection enabled, and there should be recommendations provided for installing virus protection software to address security threats. In addition, many LXI Devices with USB Drives ship with Auto-run disabled when USB drives insert, and the installed virus protection software scans any inserted USB drives. The LXI Consortium provides a document called Malware Protection White Paper under the IT Topics tab and found at This paper gives examples of products with commercial operating systems requiring virus protection. Please refer to that document for further details on recommended methods of protecting such a device. Security for Isolated System Configuration Using Router This configuration isolates the computer from the LAN and Network Administrator update software. If that software pushes updates to the computer rather than the computer pulling updates, this requires a change in Router configuration. The guide Building LXI-based Test Systems discusses several possibilities requiring Network Administrator assistance. It discusses the concept of making the Router appear to be the computer by using MAC Address Cloning and then using Port Forwarding or DMZ (Demilitarized Zone) along with enabling Ping to allow continued updates to the computer. This essentially makes the computer appear directly connected to the LAN. This configuration also allows LAN users to remote-login to the computer for test development Here is a summary of important considerations: In general, updates to computer or LXI Devices should be done during down-time of the Test System to avoid interrupting tests LXI Devices requiring virus protection usually pull virus and operating system updates and need access to a Gateway to the Internet. LXI Devices should never have updates pushed to them without coordinating with the Test System Developer to avoid interruption of device operation Avoid upgrading an LXI Device with a commercial operating system (e.g. Windows XP to Windows 7). Consult with LXI Device manufacturer for upgrade. LXI Devices with commercial operating systems may have a detachable keyboard and mouse, but these devices typically do not browse the internet or access For the Dual NIC configuration - LXI Devices with commercial operating systems moved to another subnet might be more susceptible to a virus infection. They might bring this virus back with them when returning to the Test System. 16

17 7 Recommended steps for the Network Administrator The six recommended LAN Configurations include Benefits and Cautions, which should provide good insight into the challenges presented when connecting these configurations to the company LAN. The Network Administrator can use this information in understanding how to assist the Test System Developer plan, configure, and maintain the Test System LAN Configuration. This section provides a summary of the actions the Network Administrator can take in assisting the Test System Developer: Fine-tune LAN Configuration. Review the recommended LAN Configurations with the Test System Developer and discuss alternatives based upon experience and knowledge of high performance LAN configurations and computer security standards. For example, a Wireless Router and Bridge may appear to be the only solution in some situations, but there may be other alternatives providing better security. Recommend and Help Configure Equipment. Recommend approved Routers, Switches, NIC interfaces, Wireless devices, etc., which meet company standards and the performance needs of the LXI Devices. The document Building LXI-based Test Systems, provided by the LXI Consortium at GuidesForUsingLXI, illustrates methods of configuring Routers for MAC Address Cloning, Ping, and Port Forwarding or DMZ. It also discusses using Internet Connection Sharing on Dual NIC configurations. There may be preferred methods or preconfigured equipment for these configurations. Recommend Security Methods. With this document, the Network Administrator should have a good idea of the LAN Configurations, what an LXI Device is, and how it behaves on the LAN. The Network Administrator can help the test system developer secure their Test System while meeting company security policies. In particular, the Test System Developer may need help in determining how to keep the test system computer and LXI devices up-to-date on operating system patches and virus definitions during down times for the Test System. Test System Computer Backup. During development of products, it is often important that daily regression tests execute. Production Test Systems must maintain uptime to avoid delays in product delivery. These computers must have both image and regular backups to minimize downtime. These backups must be coordinated with the Test System Developer to avoid interruption of tests. Remote Access of Test System. Gaining access to the Test System computer in the Open System Configuration is relatively straightforward to some but not everyone. A bigger challenge is allowing this in the Isolated System Configuration Using Router. This requires configuration of the Router for remote-login and other services. It may be simpler to supply a pre-configured Router that makes the Test System computer accessible. 17

18 Appendix A. Glossary of Terms Access Point (WAP Wireless Access Point) A Wireless Access Point is a device that allows wireless equipped computers and other devices to communicate with a wired network. It can also used to expand the range of a wireless network. Auto-MDIX (Medium Dependent Interface Crossover) Auto-MDIX, or Auto-crossover, is a protocol allowing two Ethernet devices to negotiate their use of the Ethernet TX and RX cable pairs. This allows two Ethernet devices with MDIX or MDI connectors to connect without using a crossover cable, a cable that reverses the TX and DX pairs on one end. ARP (Address Resolution Protocol) ARP is a protocol used by the Internet Protocol (IP), specifically IPv4, to map IP network addresses to the hardware addresses used by a data link protocol. IPv4 uses ARP over the Ethernet. The term address resolution refers to the process of finding an address of a computer in a network. CSMA/CD (Carrier sense multiple access with collision detection) This is a technique to detect when two or more devices are trying to transmit over the LAN at the same time. Operations are aborted, and each LAN Devices delays retrying to transmit by a random amount of time. CSMA/CD improves CSMA performance by terminating transmission as soon as a collision occurs, thus shortening the time required before retrying. Default Gateway In computer networking, a gateway is a node (a router) on a TCP/IP network that serves as an access point to another network. A default gateway is the node on the computer network that the network software uses when an IP address does not match any other routes in the routing table. DNS (Domain Name System) The DNS translates Internet domain and host names to IP addresses. DNS automatically converts the names we type in our Web browser address bar to the IP addresses of Web servers hosting those sites. DNS-SD (Domain Name System - Service Directory) A protocol to advertise instance service names to enable zero address configuration scenarios for networked devices. DMZ (Demilitarized Zone) The DMZ feature allows one LAN Device on the Ethernet side exposure to the Internet or WAN side. All ports forwarded vs. Port Range Forwarding, which only passes designated port. DMZ avoids having to know which ports to pass through the Router. DNS Server A server that maintains information about a portion of the Domain Name System (DNS) database and that responds to and resolves DNS queries. 18

19 Domain name This is the name given by an administrator to a collection of networked computers sharing a common directory. Part of the Domain Name System (DNS) naming structure, domain names consist of a sequence of name labels separated by periods. DHCP (Dynamic Host Configuration Protocol) The Dynamic Host Configuration Protocol is a network protocol that is used to configure devices which are connected to a network (known as hosts) so that they can communicate on an IP network. DHCP uses a client/server model where the DHCP server maintains centralized management of IP addresses that are used on the network. DHCP-supporting clients can then request and obtain lease of an IP address from a DHCP server as part of their network boot process. Firewall The Firewall screen offers Filters and the option to Block WAN Requests. Filters block specific Internet data types and block anonymous Internet requests. SPI Firewall Protection, Block Anonymous Internet Requests, Filter Multicast, Filter Internal NAT Redirection, and Web Filters make us the typical makeup of a Firewall. Hostname A hostname is the unique name, rather than an IP Address, by which a network attached to a device. The hostname identifies a particular host in various forms of electronic communication such as E- mail. HTML (Hypertext Markup Language) A simple markup language used to create hypertext documents that are portable from one platform to another. HTML files are simple ASCII text files with codes embedded (indicated by markup tags) to denote formatting and hypertext links. HTTP (Hypertext Transfer Protocol ) The protocol used to transfer information on the World Wide Web. An HTTP address (one kind of Uniform Resource Locator [URL]) takes the form: ICMP (Internet Control Message Protocol) Internet Control Message Protocol is a required protocol tightly integrated with IP. ICMP messages, delivered in IP packets, provide out-of-band messages related to network operation or improper operation. ICS (Internet Connection Sharing) ICS is the use of a device with Internet access or other Internet gateway as an access point for other devices. Microsoft introduced ICS as a feature for sharing a single Internet connection on one computer between other computers on the same local area network. It makes use of DHCP and network address translation (NAT). 19

20 IP (Internet Protocol) IP, as the primary protocol in the Internet (or Network layer in the TCP/IP model) of the Internet protocol suite, has the task of delivering packets from the source host to the destination host solely based on the IP addresses. For this purpose, IP defines datagram structures that encapsulate the data delivered. It also defines addressing methods used to label the datagram with source and destination information. IP address An address used to identify a node on an IP internetwork. Each node on the IP internetwork uses a unique IP address, made up of the network ID, plus a unique host ID. This address represents with the decimal value of each octet separated by a period (for example, , which is an IPv4 address). You can configure the IP address statically or dynamically by using DHCP. IPv4 Address Internet Protocol version 4 (IPv4) is the fourth version in the development of the Internet Protocol (IP) and the first version of the protocol to be widely deployed. Together with IPv6, it is at the core of standards-based internetworking methods of the Internet. IPv4 is the most widely used version of the Internet Protocol. It defines IP addresses in a 32-bit format, which looks like Each three-digit section can include a number from 0 to 255, which means the total number of IPv4 addresses available is 4,294,967,296 (256 x 256 x 256 x 256 or 2^32). IPv6 Address Internet Protocol version 6 (IPv6) is the latest revision of the Internet Protocol (IP), the communications protocol that routes traffic across the Internet. While IPv4 uses 32-bit addresses, IPv6 uses 128-bit addresses, which increases the number of possible addresses by an exponential amount. For example, IPv4 allows 4,294,967,296 addresses. IPv6 allows for over 340,000,000,000,000,000,000,000,000,000,000,000,000 IP addresses. IPv6 addresses consist of eight groups of four hexadecimal digits separated by colons, for example ABCD:EF12:0:0:0:0:0:3456. However, there is a short form representation whenever there are consecutive zeros: ABCD:EF12::3456. IVI (Interchangeable Virtual Instrument) IVI Drivers are sophisticated instrument drivers that feature increased performance and flexibility for more intricate test applications that require interchangeability, state-caching, or simulation of instruments. To achieve interchangeability, the IVI Foundation has defined specifications for the following eight instrument classes: DMM, oscilloscope, arbitrary waveform/function generator, DC power supply, switch, power meter, spectrum analyzer, and RF signal generator. IVI Foundation The IVI Foundation is an open consortium founded to promote specifications for programming test instruments that simplify interchangeability, provide better performance, and reduce the cost of program development and maintenance. 20

21 LAN Reset See LCI LAN Status Every LXI Device must display its current LAN operating status when powered ON. This status goes further than the LED indicators at the RJ45 connector. Many LXI Devices have a Front Panel LED indicator with a LAN Status label and others have a Utility or System menu on the Front Panel display indicating the status of the LXI Device on LAN. The LXI Standard is very specific about how this status can be displayed. A Red LED indicator or an address of represents a LAN Status fault condition, where the LXI Device is either not connected to the LAN or may have been assigned a duplicate IP Address and has disconnected itself from the LAN. LCI (LAN Configuration Initialize) LAN Configuration Initialize is an LXI Devices recessed reset mechanism (e.g., a button) on the rear or front of the LXI Device that when activated places the LXI Device s network settings to a default state. LXI Devices can also use a Front Panel menu button, safeguarded in software to avoid accidental activation. LAN (Local Area Network) A communications network connecting a group of computers, printers, and other devices located within a relatively limited area (for example, a building). A LAN allows any connected device to interact with any other on the network. LXI (LAN extensions for Instruments) LXI is the next generation instrumentation platform based on industry standard Ethernet technology and provides modularity, flexibility and performance to small- and medium-sized systems. LXI Device An LXI Device conforms to the LXI Specification and passes third party testing for validation. LXI Event An event is an abstraction of a change in the realization of a signal or condition. An LXI Event is an event occurring in an LXI Device or communicated by means of an LXI Event Message. LXI Event Message A data packet used for module-to-module communication of LXI Events in an LXI system. LXI Logo The LXI Consortium licenses a registered name and logo for use in association with products that are conformant to the standard. LXI Timing IEEE 1588 Precision Timing Protocol enables modules to have a sense of time, which allows modules to time stamp actions and initiate triggered events over the LAN interface LXI WTG (Wired Trigger Bus) The LXI Device Wired Trigger Bus implements a cabling system to interconnect multiple LXI Devices for precision, nanosecond resolution triggering. 21

22 MAC (Media Access Control) MAC is a sub-layer of the IEEE 802 specifications that defines network access methods and framing. MAC Address MAX represents a unique hardware number that identifies each device on a network. A device can be an Instrument, computer, printer, etc. Represented as 12 hexadecimal bytes in the form: MM:MM:MM:SS:SS:SS, where the M s represent the manufacturer of the LAN device. mdns (Multicast Domain Name Service) mdns is one of the discovery protocols specified for use in LXI Devices and is a protocol developed by the IETF Zeroconf Working Group. Using mdns allows a client to determine the IP address of a given host (a hostname) without the direct help of a centralized DNS server. mdns is used by printers and permits quick identification and status. Ping Ping is a utility that verifies connections to one or more remote hosts. The ping command uses the ICMP echo request and echo reply packets to determine whether a particular IP system on a network is functional. Ping is useful for diagnosing IP network or router failures. PoE (Power Over Ethernet) IEEE 802.3af Power Over Ethernet is a technology for wired Ethernet LAN that allows the electrical current, necessary for the operation of each device, to be carried by the CAT5 data cables instead of a traditional power cord. Port Range Forwarding The Port Range Forwarding opens ports on the Router that you want passed through to the Ethernet side of the Router. It is a more secure method of making connections with the Internet or WAN side of the Router, since it only opens specific ports. Configure any LAN Device forwarding ports to the Internet side for a static IP Address. Schema Schema is a document that describes a language or parameters of a language. Thus, XML Schemas provide a means of describing the structure, content, and semantics of XML documents. SCPI (Standard Commands for Programmable Instrumentation) SCPI defines a standard set of commands to control programmable test and measurement devices in instrumentation systems. The SCPI Standard builds upon the foundation of IEEE-488.2, Standard Codes and Formats. SNMP (Simple Network Management Protocol) A network protocol used to manage TCP/IP networks. In Windows, the SNMP service provides status information about a host on a TCP/IP network. Subnet A Subnet is a subdivision of an IP network. Each subnet has its own unique sub netted network ID. 22

23 Subnet Mask For IPv4, a subnet mask is a 32-bit value that enables the recipient of IP packets to distinguish the network ID and host ID portions of the IP address. Typically, subnet masks use the format 255.x.x.x. TCP/IP (Transmission Control Protocol/Internet Protocol) A set of networking protocols widely used on the Internet that provides communications across interconnected networks of computers with diverse hardware architectures and various operating systems. TCP/IP includes standards for how computers communicate and conventions for connecting networks and routing traffic. UDP (User Datagram Protocol) UDP is one of the core protocols of the Internet protocol suite. Using UDP, programs on networked computers can send short messages known as datagrams to one another. URL (Uniform Resource Locator) URL is an address that uniquely identifies a location on the Internet.. Generally, a URL specifies the connection protocol and a file name. The connection protocol can be telnet, ftp, gopher, etc., and for web pages, http is the usual protocol as in the fictitious URL VPN (Virtual Private Network VPN extends a private network across public networks like the Internet. It enables a host computer to send and receive data across shared or public networks as if they were an integral part of the private network with all the functionality, security and management policies of the private network. VISA (Virtual Instrument Software Architecture) Most of the instrument drivers communicate to the instrumentation hardware through an I/O Library. The VISA library provides I/O layers for the GPIB, VXI, PXI, Serial, Ethernet, and/or USB interfaces, while other buses can utilize either VISA or another library. W3C (World Wide Web Consortium) W3C develops interoperable technologies (specifications, guidelines, software, and tools) to lead the Web to its full potential as a forum for information, commerce, communication, and collective understanding. WINS (Windows Internet Name Service) WINS is Microsoft's implementation of NetBIOS Name Service (NBNS), a name server and service for NetBIOS computer names. Effectively, WINS is to NetBIOS names what DNS is to domain names a central mapping of host names to network addresses. Wireless Bridge. In common wireless usage, a "bridge" device allows for a wireless connection between two physically isolated wired networks. A wireless LAN bridge can interface an Ethernet network directly to a particular access point or wireless router. 23