Computing on the Edge: NEBS Criteria Levels
Tue, 15 Nov 2022 14:43:44 -0000
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In our previous blogs, we’ve explored the type of tests involved to successfully pass the criteria of GR-63-CORE, Physical Protections, GR-1089-CORE, Electromagnetic Compatibility, and Electrical Safety. The goal of successfully completing these tests is to create Carrier Grade, NEBS compliant equipment. However, outside of highlighting the set of documents that compose NEBS, nothing is mentioned of the NEBS levels and the requirements to achieve each level. NEBS levels are defined in Special Report, SR-3580.
NEBS Level 3 compliance is expected from most Telecom environments, outside of a traditional data center. So, what NEBS level do equipment manufacturers aim to achieve?
At first, I created Figure 1 as a pyramid, not inverted, with Level 1 as the base and Level 3 as the peak. However, I reorganized the graphic because Level 1 isn’t really a foundation, it is a minimum acceptable level. Let’s dive into what is required to achieve each NEBS certification level.
NEBS Level 1
NEBS Level 1 is the lowest level of NEBS certification. It provides the minimum level of environmental hardening and stresses safety criteria to minimize hazards for installation and maintenance administrators.
This level is the minimum acceptable level of NEBS environmental compatibility required to preclude hazards and degradation of the network facility and hazards to personnel.
This level includes the following tests:
- Fire resistance
- Radiated radiofrequency (RF)
- Electrical safety
- Bonding or grounding
Level 1 criteria does not assess Temperature/Humidity, Seismic, ESD or Corrosion.
Operability, enhanced resilience, and environmental tolerances are assessed in Levels 2 and 3.
NEBS Level 2
Figure 2. Map of Seismic Potential in the US
NEBS Level 2 assesses some environmental criteria, but the target deployment is in a “normal” environment, such as data center installations where temperatures and humidity are well controlled. These environments typically experience limited impacts of EMI, ESD, and EFTs, and have some protection from lightning, Surges and Power Faults. There is also some Seismic Testing performed on the EUT, but only to Zone 2. While there is no direct correlation between seismic zones and earthquake intensity, in the United States, zone 2 generally covers the Rocky Mountains, much of the West and parts Southeast and Northeast Regions.
NEBS Level 2 certification may be sufficient for some Central Office (CO) installations but is not sufficient for deployment to Far Edge or Cell Site Enclosures which can be exposed to environmental and electromagnetic extremes, or in regions covered by seismic zones 3 or 4.
NEBS Level 3
NEBS Level 3 certification is the highest level of NEBS Certification and is the level that is expected by most North American telecom and network providers when specificizing equipment requirements for installation into controlled environments.
Level 3 is required to provide maximum assurance of equipment operability within the network facility environment.
Level 3 criteria are also suited for equipment applications that demand minimal service interruptions over the equipment’s life.
Full NEBS Level 3 certification can take from three to six months to complete. This includes prepping and delivering the hardware to the lab, test scheduling, performance, analysis of test results, and the production of the final report. If a failure occurs, systems can be redesigned for retesting.
Conclusion
While environmental, electrical, electromagnetic, and safety specifications described in NEBS Level 3 certification, it is the minimum required for deployment into a controlled telecom network environment; these specifications are only the beginning for outdoor deployments. The next blog in this series will explore more of these specifications such as GR-3108-CORE and general requirements for Network Equipment in Outside Plant (OSP). Stay tuned.