SAN JOSE, Calif. — There’s no clear end in sight for the protocol wars in the Internet of Things, says the chief technologist of a building controls startup. The CTO of Enlighted, which developed its own 802.15.4 protocols, believes the outlook for Zigbee is particularly dim.
The IoT needs a set of open APIs and protocols that work with a variety of physical-layer networks, says Tanuj Mohan. In this way, he feels, IoT networks should act more like IT nets. Mohan was a co-founder of Enlighted and is a networking expert who worked at Cisco, Novell, and Tropos and built multiprotocol routers at Hughes.
“Anyone who tries to build a physical layer and drive a software stack based on it all the way up to the application layer is a fool,” he says:
The IP and network layer should have nothing to do with the media. The last-mile protocols have some play, but they are not as important as people make them out to be. It doesn’t matter if[nodes] talk over one protocol or another. In any case, you will need mediation devices.
Today Zigbee is the most cost effective, but tomorrow WiFi will figure it out. Networks talk SNMP or CORBA — every few years there’s a new management protocol. In some sense, that’s what will happen in IoT, it will keep moving, and people will need open APIs.
Mohan criticized the 250 kbit/s Zigbee standard as too slow and complicated for use in building automation:
You don’t want the network to be the bottleneck, and Zigbee is one of the slowest of any protocols I know. It has some application in the home market, but in the commercial space it won’t work. Zigbee may be used in some large buildings, but it will take a lot of handholding and custom engineering and that will cost a lot.
For example, if someone streams on WiFi, the Zigbee doors may not open. So you need to make sure to use different wireless channels on every floor. You cannot sell such an approach through the existing ecosystem of electricians because they aren’t sophisticated enough in RF.
Zigbee did not learn from the networking industry. The deployments today require so much handholding the never got out of the early-adopter phase. Lighting control guys don’t understand the network security they need. It’s a protocol that will take forever to catch up. If a systems company like Aruba or Cisco led Zigbee, they would have been way ahead.
Even emerging alternatives such as 6LoWPAN are not ideal given the big overhead in packet headers for Internet Protocol, he says. “IP was not done for low-bandwidth apps, so they are trying to retrofit it to make it more efficient, but we need someone with a clean slate to think it through. It may come from left field, perhaps with new spectrum.”
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