Connecting with Cat 6: Don't worry, be happy
Despite recent concerted efforts by industry experts on cable, connectors, and testing, a Category 6 cabling standard remains mired in details and unresolved technical issues (see "Ask Donna," page 8)
Despite recent concerted efforts by industry experts on cable, connectors, and testing, a Category 6 cabling standard remains mired in details and unresolved technical issues (see "Ask Donna," page 8). As NORDX/CDT Inc.'s senior product manager Paul Kish opined during a luncheon at the BICSI Spring Conference in Fort Worth, TX, it's no longer the cable, it's the other stuff-connector far-end crosstalk, test plug requirements, and the debate over patch-cord test procedures. "It's about what components, what connectors, and interoperability and compatibility issues," Kish says.
But whatever the final shape of Category 6 and whenever it lands, NORDX/CDT (Montreal) is among several other companies and distributors trying to convince the industry that there's no need to worry about or wait for Category 6. Just be careful.
NORDX/CDT, for example, is heralding the connectivity products and unshielded twisted-pair cables in its new IBDN System 4800LX structured cabling system as "designed to perform well above the standards." Or, as its trademarked definition puts it, Beyond Category 6. With the 4800LX, and similar campaigns by Anixter Inc. (Skokie, IL) and Graybar (Clayton, MO), the prevailing structured cabling marketing pitch is: Leave your Category 6 backward-compatibility and headroom worries at the door. NORDX/CDT says the 4800LX "may be the last cabling system you will need." The company's 25-year guarantee ensures all components will comply with Telecommunications Industry Association/Electronic Industries Alliance (TIA/EIA-Arlington, VA) standards-and if not, NORDX/CDT will correct the failure, including parts and labor, for free.
Meanwhile, Kish, an active participant in TIA/EIA standards-setting procedures, is urging the standards committee to consider what he terms insertion-loss deviation (ILD) as a key parameter for determining Cat 6 component interoperability. ILD is caused by a secondary signal that is riding on top of the receive signal, appearing as a noise source at the receiver. In worst-case scenarios during Category 5 channel tests, Kish says, NORDX/CDT found that the signal-to-noise ratio due to ILD noise resulted in a significant impedance mismatch between components, making a Cat 5 channel borderline compliant for 100Base-TX applications. While acknowledging that "this situation is unlikely to occur in practice except when the user cords and cables are at the extreme ends of the tolerance range," Kish says it points out the need for all components in a Category 6 structured cabling system to be designed to work together "as part of an end-to-end solution."
Anixter would agree. In fact, the discerning network solutions distributor has given NORDX/CDT's 4800LX system its stamp of approval, verifying that it either meets or exceeds performance criteria established on Anixter's ALC 7 methodology. ALC (Anixter Levels Channel) defines how all the components of a structured cabling system work together. Data-cabling performance is determined by how well the entire channel performs-cable, connecting hardware, information outlets, and patch cords. Products that pass ALC testing are considered viable for running both current and future applications, having met minimum levels for eight telecom standards.
But at the recent BICSI Spring Conference, Anixter and eight other partners took the components-must-work-together battle cry to another level-Levels XP, that is. The so-called "extended-performance" criteria is groundbreaking, in that unlike ALC, XP tests network cabling systems with active data signals. Passive electrical signal testing (such as for attenuation and crosstalk) doesn't give a true indication of how well the system would work when active signals are transmitted, Anixter says. So it developed Levels XP (XP 6 and XP 7) based on its own findings that revealed a significant correlation between corrupted data and mismatched components.
Category 6 cabling-system components that meet XP 6 specifications typically have 60,000 frame errors out of four million, with bit errors at 1.5%, reflecting a typical improvement over a Category 5 system of 70%. Typical Levels XP 7 criteria are 17,000 frame errors out of four million, bit errors at 0.45%, reflecting a 92% improvement over Category 5.
Anixter suggests that its XP specifications mean minimum industry standards aren't good enough. "Network industry standards reflect minimum requirements and therefore ensure only minimal performance," explains Pete Lockhart, Anixter's vice president of technology and product design. "Existing industry specifications can be compared to manufacturing standards for automobile tires. Although the brands meet the same manufacturing requirements, you would ultimately damage your vehicle. Similarly, mismatched network components may comply with minimally prescribed industry standards but were never designed to function together."
Cooperating with Anixter in the XP specification are Belden Wire & Cable Co., Panduit Corp., the Siemon Co., CommScope Inc., Berk-Tek, an Alcatel company, Ortronics Inc., Krone Inc., and Lucent Technologies.
Graybar, another major cabling-media distributor, is also touting beyond Category 6 component performance under its new VIP (Verified Independently for Performance) 2000 program, verifying cabling systems for usable bandwidth up to 250 MHz, compared to the 200-MHz Cat 6 minimum currently being considered. But unlike Anixter, Graybar puts its vendors' products through third-party testing conducted by Intertek Testing Services/ETL.
According to national marketing manager Rob Bezjak, the ITS/ETL testers "make random selection of those items from our inventory, then determine the pass/fail status of our channels. And they suggest corrective actions if necessary."
Adds Dennis DeSouza, Graybar vice president of communications data marketing, "The only way to ensure a customer is purchasing the latest in technology is to purchase items subject to random sampling. We have returned previous generations of some Category 6 products from our inventory to provide our customers with the highest performance available."