Designing for the Edge: PowerEdge and NEBS
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Summary
Compute infrastructures are evolving to meet the demand for low latency, distributed computing outside the data center. These edge environments can present unique challenges that traditional servers do not address. Dell PowerEdge has led the way in designing and delivering reliable servers built for the edge.
Introduction
As computing expands beyond the data center, there is a need for enterprise-grade servers that offer reliable performance in environmentally challenging facilities. A traditional data center can provide power redundancy, climate control, and physical security. However, a server deployed in a telephone network's central office, a manufacturing facility, or in a retail backroom may be more exposed to the effects of natural disasters, extreme temperatures, high humidity, airborne contaminants, high altitude, lightning, impact shock, vibration, or EMI emissions. Dell Technologies understands the unique challenges of these environments, and our engineering teams design our edge servers to be certified rugged for NEBS.
What is NEBS Testing?
The North American telecom industry requires service providers and edge computing providers to be Network Equipment-Building System (NEBS) compliant to ensure network integrity, compatibility, and safety. Being NEBS compliant indicates that the products and equipment operate reliably at the edge. Therefore, network operators need to invest in suppliers who ensure their performance through rigorous testing.
With the adoption of 5G, rapid network expansion, and the need for carriers to successfully manage their infrastructure during extreme weather events, the demand for NEBS-compliant devices is only increasing.
NEBS Test Levels
NEBS compliance ensures that a server meets the GR-63-CORE and GR-1089- CORE standards and is made up of various levels that distinguish certain aspects of testing. Each one verifies a different performance specification with operational requirements. For example, the lowest level of NEBS compliance, Level 1, is used for prototypes in laboratory trials. By contrast, the highest level, Level 3, is typically required for equipment deployed in a communications network.
Many standards fall within the scope of NEBS. The standards most used are:
- GR-1089-CORE - Electromagnetic compatibility and electrical safety
- GR-63-CORE - Physical protection
The NEBS Levels are described below. Note that successive levels incorporate previous level requirements.
- NEBS Level 1: Addresses equipment safety measures and requirements for GR-63-CORE and GR-1089-CORE standards. Typically used by service providers for prototype equipment for trial and limited deployment equipment.
- NEBS Level 2: Addresses equipment operability in controlled environments such as data centers. Level 2 includes all requirements of Level 1 with some added level of operability reliability.
- NEBS Level 3: Determines that the equipment meets all the requirements of GR-63-CORE and GR-1089-CORE. This provides the highest assurance of product operability. Most TCGs require Level 3 before acceptance/installation on the networks.
NEBS Level 1 | NEBS Level 2 | NEBS Level 3 |
GR-63
GR-1089
|
GR-63
GR-1089
|
GR-63
GR-1089
|
Table 1. NEBS Levels
NEBS Testing
NEBS testing is designed to simulate conditions at the edge. The following section shows the test areas in more detail.
Thermal and Altitude Exposure
Servers deployed at the edge can be exposed to extreme temperatures, humidity, or high altitude. These conditions can occur during transport, storage, or operation. This testing ensures that a server functions reliably during and after exposure.
Test | Server State | Test Conditions |
Non-Operational Test | Off |
|
Operational Test | On and running system stress |
|
Simulated Fan Failure | On and running system stress |
|
Altitude Exposure | On and running system stress |
|
Table 2. Thermal and Altitude Testing
Flame Resistance
In rare instances, a server can malfunction and produce sparks or fire. This testing ensures that the flames do not escape from the server chassis and damage adjacent people, equipment, or facilities. The fire must be confined to a failing chassis, and the chassis should self-extinguish and dissipate the smoke. In addition, the server materials must be flame retardant to minimize the spread of flames.
Shipping Impact Survivability
While shipping partners do their best to handle equipment carefully, accidents happen. When a packaged server is dropped, it should not sustain significant damage. NEBS testing ensures the server packaging material protects the server during typical shipping scenarios. This testing includes drops from heights up to 1M (weight dependent) on all axes.
Seismic and Vibration Robustness
A server must withstand transportation vibration and earthquakes up to 8.3 on the Richter Scale. Drives, risers, memory, PCIe devices, and other components should not dislodge, break, become loose, or stop functioning after experiencing seismic or transportation vibrations. A server is subjected to a prescribed motion waveform that simulates typical earthquake motion. This motion occurs in multiple axes over time, and once complete, the server is checked for damage and proper functionality. The server must not sustain permanent damage and should function normally after the test.
Airborne Contaminants
Servers deployed to edge sites such as factory floors or cell towers may encounter contaminants not seen in a clean, climate-controlled data center. In this testing, servers are exposed to various contaminants over approximately ten days and should function properly after the test. The fan filter must block contaminants and allow the server to deliver reliable performance. The filter must be replaceable while the server is operational. The exposure testing includes gas with corrosive material and hygroscopic sand-like contaminants
Acoustic Noise
High-performance fans move an enormous amount of air and can be loud. Therefore, NEBS testing includes checking the sound power while running fans at maximum speed to ensure OSHA compliance. The server should be less than 78dB at max fan speed in Telco Room testing and less than 83dB at max fan speed in Power Room testing.
ESD Robustness
Electrostatic discharge happens. Servers must function as designed after exposure to ESD. This exposure testing includes close and open chassis scenarios that simulate a field repair scenario. ESD testing includes 8kV contact discharge and 15kV air discharge
EMI Emissions and Immunity
Electromagnetic interference, or EMI, is present in areas with electronic equipment. EMI can be exceptionally high when lots of electrical equipment is placed in confined spaces. This testing ensures that a server does not radiate emissions beyond the max allowed and that it can survive exposure to emissions from other devices.
Lightning and Surge Robustness
Edge servers may encounter periodic site lightning. Given proper grounding, the server must survive a power surge from lightning. This test simulates the power surge generated from a lightning strike and the server's ability to function correctly afterward.
Designing for the Edge
Dell works with customers and partners to understand the unique challenges of operating outside the data center. We use this knowledge and experience to build best-in-class, enterprise-grade servers that offer reliable performance at the edge. Some edge servers offered by Dell include the PowerEdge XR11, XR12, and XE2420. The following section highlights some of the design elements of our edge servers.
Figure 1. Dell PowerEdge XE2420 with optional bezel filter
Rugged, Flexible, Compact Chassis Options
- Hot and cold aisle access options
- AC and DC power supply support
- Short chassis depth for confined spaces
- Support for full-size PCIe cards
- Individual locking mechanisms prevent dislodging of add-on cards
- Optional bezel air filter to protect against airborne contaminants
Optimized Thermal Performance
- High-performance fans
- Minimal in-chassis airflow obstructions
- Unique chassis designs eliminate preheated air across add-in devices like GPU accelerators
- Configurable thermal management with iDRAC
Figure 2. Dell PowerEdge XR12
Conclusion
With the need for organizations to integrate products from many vendors into large, robust systems, they need to be confident that these products are resilient. NEBS testing ensures that these products meet a high standard of reliability and longevity at the edge. So, choosing a Dell PowerEdge server that is certified rugged for NEBS gives you the peace of mind that your server can perform in rough environmental conditions at the edge, with the guaranteed reliability of Dell PowerEdge.
References
- Telcordia. NEBS Requirements: Physical Protection. Generic Requirements, GR-63-CORE, Issue 5, December 2017
- Telcordia. Electromagnetic Compatibility (EMC) and Electrical Safety - Generic Criteria for Network Telecommunications Equipment. Generic Requirements, GR-1089-CORE, Issue 7, December 2017