802.11 Standards Drift and Interoperability Certification

by Matthew Gast

Related link: http://www.nwfusion.com/columnists/2002/1216edit.html?vo




The original reason the
Wi-Fi Alliance
formed was to promote interoperability. Back when 2 Mbps DS cards were state-of-the-art, seamless interoperability was not assured. As a result, the industry got together to do interoperability testing and certification, which is the right thing to do with a complex, multi-vendor standard. Buyers generally will hang on to their money until bleeding-edge gear has been proven interoperable and standards-compliant. The Wi-Fi Alliance has done their job well. Interoperability between different 802.11 vendors is never a problem these days, so the certification has faded into the background.




The question Keith Shaw poses is one of user expectations. If companies buy gear with proprietary extensions, users might begin to expect the extension to work everywhere. In an enterprise network, you can mandate that all the APs use the TI chipset with the non-standard 22 Mbps PBCC mode, but there's no guarantee you'll get the same performance everywhere. Shaw also wonders what happens if the vendors drift too far from the standards.




Standards drift should not be a problem. The Wi-Fi certification will continue to assure interoperability at the standardized speeds. If you drift too far from the standards, you can't use the Wi-Fi certification mark. I'm also not too worried by the fact that the high-speed extension might not work everywhere. Even if I can get 22 Mbps to a hot spot AP, does the hot-spot really have that fast a link to the outside world? Probably not, though I'm not the hot spot expert others are. In October, the Wi-Fi alliance unveiled a new
certification mark
that specifies interoperability and operational speed. The logo looks the same and is still recognizable, but it clearly indicates that the product has been certified at either 11 Mbps or 54 Mbps, vendor claims to higher speeds notwithstanding.




(A final note: Vendors often try to compete on the basis of proprietary extensions to a standard. Real innovation happens when companies use the standard as a basis for further development within the specified framework. Many imaginative products are standards-based, but have a novel take on how to implement the standard. These products are built by inventors who see the standard as a starting point, not a straitjacket. Incidentally, this is one of the points I really like about Vivato's switch. They used the standard as the definition of basic communication, and added a whole lot of RF intelligence. The product complies with all the relevant 802.11 standards, but is still radically different from anything else that preceded it.)