6LoWPAN Vs ZigBee

Written by Akiba

Wednesday, 04 March 2009

After the euphoria of the Zigbee/RF4CE announcement wears off, I still have this lingering sense that the picture isn't really complete. Although the coordinated press releases of the Zigbee Alliance members kind of pounded the message into everyone's brain and cements a second huge potential market for Zigbee, it pretty much just means that along with being an electrical metering protocol, it will also be known as a remote control protocol. This is actually really good news, but chances are that it will end up similar to Bluetooth which was never really able to shake its reputation as a wireless earpiece protocol. One clear thing is that Zigbee now has two large markets under its belt and that's important because it's pretty much the only standard wireless sensor networking protocol that can claim this. This makes it king of the hill, only it's members shouldn't be too complacent because that hill is still really small. Being an industry leader has its advantages such as having a greater chance of survival but unfortunately doesn't necessarily mean that consumers will adopt it. Sure, it can be forced down people's throats by having a Zigbee enabled meter or a Zigbee/RF4CE remote control to come with your Sony Bravia, but if the Zigbee Alliance isn't careful, that's pretty much where it'll end. The real danger for Zigbee is in assuming that because they have the largest potential markets, that consumers will flock to the technology. The true test for any technology is in adoption. This is where 6LoWPAN has the advantage. If you don't know, 6LoWPAN is an IETF draft standard that specifies how IPv6 frames will be carried over the 802.15.4 wireless protocol. The benefit that this protocol, or actually I would be more correct in saying header compression scheme, has over Zigbee is that you can use TCP/IP as the communications mechanism. Notice I didn't mention anything about 6LoWPAN being better than Zigbee, or more efficient, faster, lower power, tastes great, or less filling. Those would be fighting words and I don't want to set off a religious war. The truth is that technological superiority doesn't really matter in terms of adoption except for technical purists, aka geeks. What really matters is that 6LoWPAN uses TCP/IP and TCP/IP doesn't have an adoption curve. There is a huge amount of existing infrastructure, developers, software, standards, and knowledge that people just kind of accept it like air. It's what most of the world uses on a daily basis, whether they know it or not. The weakness of 6LoWPAN is that they don't have a real market for the protocol at the moment and it's mostly because of some technical issues. The main problem lies in the fact that they don't have any standards in place to govern device interoperability of each wireless sensor node. Zigbee spent a lot of time on device interoperability for the nodes and defined standard device profiles that behave in well documented ways. This means that one node can discover what services another node provides, and access those services in a standardized way. They also set up the test labs with testing equipment, checklists, training, certification procedures, and pass/fail criteria to ensure that the devices that make it through the testing and get the Zigbee certified logo adhere to these profiles. Although many people will probably bash me and say that it still doesn't guarantee interoperability, it's still better than anything that 6LoWPAN currently has. Well, I'd better make my point quickly or else I'm going to end up being hated by both groups. My point is that Zigbee has the device interoperability specification and testing infrastructure in place and it also has access to two potentially large markets that are gateways into the consumer home. 6LoWPAN has access to a huge amount of infrastructure, a disgustingly large pool of protocol developer geeks, and TCP/IP which is the lingua franca of communications all over the world. When I said that something felt like it was missing, I really meant that Zigbee needs 6LoWPAN and conversely, 6LoWPAN needs Zigbee. If they could somehow put aside their ideological differences and pointless debates on protocol efficiency, and somehow combine their strengths, this could be a rare case where the sum is exponentially greater than its parts. Not only would something like this re-define how people think of the internet and interact with it, it would also bring some really huge guns into the game…like on the order of Cisco, Microsoft, Google, and Intel. This would be on top of companies like Sony, Samsung, Panasonic, and Philips that came along with RF4CE. It would also bring a shower of media interest, funding, and most importantly, excitment back into the tech industry which, in this humble open-source developer's opinion, is something that it is desperately in need of. So yes, the Zigbee and RF4CE tie up is great, but the real holy grail is if Zigbee and 6LoWPAN could settle their differences and work together to really create…dare I say it…the "Internet of Things". Source: http://freaklabs.org