A White Paper from the Experts In Business-Critical Continuity™.
Successful Design and Test Methodology for NEBS Creating Equipment that Meets Carrier Requirements using Open Standards
Joe Finlayson, Platform Integration and Verification Engineer Larry B. Terry, Strategic Business Development June 2007
Table of Contents 3 Executive Summary 3 Introduction 4 Design for Compliance 4 Test for Compliance 5 NEBS Program Management 5 Test Results and Reports 5 NEBS in Practice 6 Appendix
2 Successful Design and Test Methodology for NEBS EmersonNetworkPower.com/Embedded Computing
Executive Summary The acronym NEBS is more than just another term that permeates the telecommunications vernacular. It defines the conformance requirements and standards that regulate the quality and reliability of equipment used in telecom networks. This white paper introduces the key considerations to achieve NEBS compliance when designing and testing communications servers based on open standards such as AdvancedTCA®. Introduction Network Equipment Building System (NEBS) requirements are defined in Telcordia SR3580 and primarily consist of compliance to Telcordia GR-63-CORE and GR-1089-CORE. NEBS certification is required by North American Regional Bell Operating Companies (RBOC), Competitive Local Exchange Carriers (CLEC), International Exchange Carriers (IXC), and other networks operators prior to deployment in their networks. In addition to meeting NEBS requirements, some of the North American carriers require additional testing to be performed, most commonly known as “NEBS Supplementary Requirements”. European carriers generally require proof of compliance to a similar set of standards generated and maintained by the European Telecommunications Standards Institute (ETSI). These standards are primarily EN 300 019, EN 300 386, ETS 300 753 and EN 300 132. While the requirements are very similar to NEBS, the limits and specific tests may vary based on the differences in climate and geography between the U.S.A. and Europe. Targeting the standards above, in addition to meeting the legal product safety and electromagnetic compatibility (EMC) requirements, generally result in satisfying a majority of the carrier’s requirements globally.
3 Successful Design and Test Methodology for NEBS EmersonNetworkPower.com/Embedded Computing
NEBS is a term which defines the conformance requirements and standards that regulate the quality and reliability of equipment used in telecom networks. Design for Compliance The process of obtaining NEBS compliance begins in the conception phase of a product. Product requirement documents are reviewed to ensure that the product is designed to meet the corresponding defined requirements and that full test coverage is applied. Detailed design reviews of both electrical and mechanical aspects of each system component take place early in the product program definition.
ESD testing being performed at the Emerson Network Power test facility in Tempe, Arizona
Proven design guidelines and measured care are needed in several areas including PCB layout, product enclosure shielding effectiveness, I/O filtering, surge suppression, bonding and grounding, thermal performance and mechanical structural integrity. This increases the probability of passing test results during the NEBS pre-testing efforts, which are aimed at minimizing product release delays and the financial burden of re-design and re-test.
Test for Compliance Designing for compliance through deep experience is not enough to meet or exceed NEBS requirements. The product design must also be validated. It is imperative that as soon as the first prototype hardware arrives, verification testing commences as part of overall product development validation phase. A test plan is generated from the product requirement document to identify the test cases that are likely to fail or marginally pass. The following is a short list of test requirements which are likely to cause issues and require pre-testing:
Thermal testing being conducted.
Three Emerson Centellis 3600 series communications servers mounted in a 42U rack being evaluated to the NEBS Zone 4 Earthquake Test criteria.
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Radiated emissions
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Conducted emissions
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ESD
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Lightning
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Power transients
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Operational temperature and humidity
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Acoustic noise
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Office vibrations
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Fire spread
Many telecom equipment manufacturers (TEMs) choose to plan and execute their own NEBS testing. This may be desirable if a supplier’s product or platform contributions are an element of the overall customer solution. In this case, the TEM must ensure that designated products are designed to pass NEBS testing. And it is critical that a supplier can provide direct support to TEM engineering teams to ensure that all of the documentation is available to assure the eventual NEBS qualification of the final customer solution, including support if issues are uncovered during test. Suppliers must have a process for analyzing test results and feeding them back to the design teams. Changes must be tracked using integrated design methodology tools to ensure proper resolution prior to executing the formal NEBS testing phase. In the event that third-party content is integrated by a supplier into the platform, the same procedure must be followed with regards to the testing. However the feedback is provided to the vendor being integrated using agreed and shared processes to ensure proper resolution. Once the final general availability (GA) candidate hardware is received, product or platform staging and soaking processes are required. In order for the equipment to be ready to go through a formal NEBS qualification program, it must be stable and run error free for several power-on hours, typically up to two weeks. Once this milestone is reached, the product or platform equipment can be deemed ready to begin the formal NEBS qualification testing.
Centellis 3600 in a frame-level NEBS configuration.
This formal NEBS qualification program must be executed at an Nationally Recognized Testing Laboratory (NRTL) accredited by the Occupational Safety and Health Administration (OSHA). 4 Successful Design and Test Methodology for NEBS EmersonNetworkPower.com/Embedded Computing
Preparation is the key to a successful NEBS program and begins with the test plan. The Emerson Centellis 3600 series of communications server and AdvancedTCA blades being evaluated to the NEBS Fire Spread criteria.
An NRTL is recognized as meeting the stringent quality requirements set forth by OSHA, defined as:
“… an organization that OSHA has "recognized" as meeting the legal requirements in 29 CFR 1910.7. In brief, these requirements are the capability, control programs, complete independence, and reporting and compliant handling procedures to test and certify specific types of products for workplace safety. This means, in part, that an organization must have the necessary capability both as a product safety testing laboratory and as a product certification body to receive OSHA recognition as an NRTL.” NEBS Program Management
Centellis 3600 with ignition line burner installed.
Preparation is the key to a successful NEBS program and begins with the test plan. Items such as test configuration, hardware serial numbers, system exercising software with pass/fail criteria, test classification, system operating frequencies and thermal characteristics are all identified in the test plan. Typically, additional product or platform regional or localization testing may be performed. Test requirements are captured and managed as part of this management plan. Generating a schedule that meets the release goals is integral to successful NEBS program. Understanding the scope of the testing and having a good working relationship with the NEBS test facility ensures that there is the right balance of plan aggression and realism in the schedule.
Centellis blade (side 1) before Fire Test.
Resource allocation is another point which must be considered. The program will only flow smoothly if there are adequate test engineers on site with expertise encompassing both the equipment under test and the tests to which that equipment is being subjected. In the case where third-party products are subjected to testing, the manufacturer must properly plan resources to assist and support the testing at the third-party lab for anywhere from two-four months.
Test Results and Reports The final deliverable of a NEBS program is the test report. It is crucial that detailed reviews of the test reports are performed to ensure acceptance by carriers. When test reports are submitted to the carrier, suppliers must be able to authoritatively address questions or concerns highlighted, discuss corrective actions that have been taken or can be pursued and stand by the product solution and the test report. Test reports should be available for “standard” or reference configurations and a supplier should be able to provide customized NEBS testing for special configurations or test conditions.
NEBS in Practice Centellis blade (side 1) after completion of Fire Test.
Many TEMs have evolved from simply providing hardware and software to providing user-centric applications and services. And many are taking on responsibility for managing carriers’ networks, leaving carriers to focus on the customer experience. These TEMs are now constantly challenged with balancing the cost and time-to-market requirements with the ability to design NEBS-compliant, generally available platforms for compelling services to new and existing markets. Over 20 years of NEBS expertise within the Embedded Computing business of Emerson Network Power has proved that this balancing act can be achieved. Emerson provides tier 1 TEMs with framelevel, custom configured versions of the Centellis™ 3600 series AdvancedTCA communications server, certified to the North American requirements (safety, EMC and NEBS Level 3) and European CE Mark and ETSI requirements.
Centellis blade (side 2) after completion of Fire Test.
5 Successful Design and Test Methodology for NEBS EmersonNetworkPower.com/Embedded Computing
Appendix NEBS History NEBS is the sole property of Telcordia Technologies (formerly Bellcore). Bell Communications Research (Bellcore) was a group spun off during the divestiture of AT&T in 1984 as a research arm for the Regional Bell Operating Companies (RBOC). AT&T had developed design standards (now known as GR-63-CORE and GR-1089-CORE), which were passed on to Bellcore, who in turn implemented these standards for telecom equipment designed for installation into any of the RBOC telephone networks. Bellcore was funded by the RBOCs up until 1996, when SAIC bought Bellcore. Part of the purchase of Bellcore included dropping the use of “Bell” in the name. The company is now known as Telcordia Technologies.
NEBS Level 1, 2, 3 NEBS testing is divided into three levels. A special requirements document from Telcordia Technologies, SR-3580, outlines what tests are required for each level. The most common question is “What level should I test to?” Generally, the RBOCs require level 3 testing (plus additional carrier specific tests) for any product designed for installation into their central office (CO) configuration. Some exceptions are made for co-located equipment or customer trials, which minimally requires level 1 testing.
6 Successful Design and Test Methodology for NEBS EmersonNetworkPower.com/Embedded Computing
About Emerson Network Power Emerson Network Power, a business of Emerson (NYSE:EMR), is the global leader in enabling Business-Critical Continuity™. The company is the trusted source for adaptive and ultra-reliable solutions that enable and protect its customers’ business-critical technology infrastructures. Through its Embedded Computing business, Emerson Network Power enables original equipment manufacturers (OEMs) and systems integrators to develop better products quickly, cost-effectively and with less risk. Our business was strengthened by the acquisition of Motorola's Embedded Communications Computing group, which has driven open standards and pioneered technologies based on them for more than 25 years. This positions Emerson Network Power as the recognized leading provider of products and services based on open standards such as ATCA®, MicroTCA™, AdvancedMC™, CompactPCI®, Processor PMC, VMEbus and OpenSAF™. Our broad product portfolio, ranging from communications servers, application-ready platforms, blades and modules to enabling software and professional services, enables OEMs to focus on staying ahead of the competition. Manufacturers of equipment for telecommunications, defense, aerospace, medical and industrial automation markets can trust Emerson’s proven track record of business stability and technology innovation. Working with Emerson helps them shift more of their development efforts to the deployment of new, value-add features and services that create competitive advantage and build market share. Emerson’s commitment to open, standards-based solutions and our deep understanding of the embedded computing needs of OEMs provide the foundation for the market to look to us for leadership and innovation.
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