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What you need to know about NEBS

Apr 17, 20033 mins
Data CenterNetwork Switches

* Bulletproofing systems the telco industry way

In North America, telephone communications has become something we almost never think about.  A good part of the reason for this is something called NEBS.

NEBS is the abbreviation for the Network Equipment Building System, a set of technical requirements with one basic purpose: to make network switches bulletproof.  The standard was developed internally at Bell Labs – and later, at Bellcore (now Telcordia Technologies)  – in the days when it was the “deep think” part of the Bell Telephone system (and you thought it only helped bring us Unix!)  Does it work?  You bet.

Telephone companies starting with Ma Bell and then, after divestiture, the “Baby Bells” (now called RBOCs – regional Bell operating companies) and LECs (local exchange carriers) rely almost entirely on NEBS-compliant hardware for their central office telephone network switching.  Doing so assures them that the equipment they buy meets clearly identified standards regarding temperature and humidity, resistance to fire, equipment handling, earthquake survivability, vibration (both in the office and when being transported), airborne contaminants and acoustic noise. 

Recently, a few vendors, including Dot Hill and Sun have offered NEBS storage systems as well.  Additionally, some service providers such as ZeroNines provide client companies with continuous data access by relying on NEBS-compliant switches within their data assurance infrastructure.

If you are interested in knowing more about NEBS, a detailed description of compliance requirements is available at

If you look at vendor sites, keep in mind the following:

There is a difference between products that are “NEBS certified” and those that are “NEBS compliant”, although the distinction may only be that “compliant” products have not been submitted for the appropriate set of tests. 

A more important differentiator is the three levels of NEBS, which offer enterprises varying levels of assurance: 

* Level 1 is aimed at office class environments, and is intended to minimize system degradation. Generally, it is used for prototyping and for noncritical systems.

* Level 2 is a rarely referenced middle ground intended for “failure tolerant services.”  It should be fine for data centers that are confident they can provide a controlled environment (if you know of one of these, please let me know), but doesn’t apply to disaster recovery.

* Level 3 addresses the needs of “carrier class” environments in telecomm-speak.  We data center folks, much more humble, tend to refer to this as “bulletproofing.”  Look here for maximum availability for critical systems.

Clearly there is a big difference within the standard at these three levels.  Is the extra value going to be meaningful to your site?  In this case, as in most others, it makes sense to invest in what is appropriate, and to avoid overbuying.

Many managers don’t know much about NEBS, and some may never require it. But if your shop needs to be resilient in the face of an earthquake that measures 8.3 on the Richter scale, or if you are subject to lightening strikes that hit 15,000 volts, or if you are simply the kind of manager who feels most comfortable when wearing both a belt and suspenders, it is a given that NEBS Level 3 is for you.