Wireless Mesh Networks

Roland Piquepaille writes "Robert Poor is CTO of Ember Corporation. He contends that point-to-point or point-to-multipoint networks typical of industrial wireless communications systems have limited scalability and reliability. 'In contrast, wireless mesh networks are multihop systems in which devices assist each other in transmitting packets through the network, especially in adverse conditions. You can drop these ad-hoc networks into place with minimal preparation, and they provide a reliable, flexible system that can be extended to thousands of devices.' The article is pretty technical and contains several illustrations and a case study about the deployment of a wireless mesh network in a water treatment plant. Check this column for Poor's conclusions or read this Sensors article if you have more time."

Comments

IPsec is a requirement

[puzzled]

The only way to make something like this work is to have a solid L3 encryption system between the remote and the head end - intermediate stations will certainly get snooped.

IPsec is the way to go, but its still something of a hassle on IPv4. I've seen a lot of noise about mesh networks - this isn't really going to take off until IPv6 gets moving under its own power - perhaps another five years.

Re:IPsec is a requirement

[jaavaaguru]

If I actually care about something being secure, it's either done through SSH (or scp to copy files), or I use SSL encryption on my ,a href="http://jabber.org">instant messaging, or PGP encrypted e-mails. I don't care if someone's able to tell who the recipient is and what the subject is. My ISP probably logs that anyway. Wireless networking as it is now supports all that and more. What's wrong with it then?

Good till everyone has one...

[James_Duncan8181]

Well, I'll buy it as working for a small business but you would find it very difficult to have a big network as all of the network chatter takes up an increasing amount of spectrum. This is the same problem P2P networks have (a similar arch) and they can only solve it by having a network that cannot see all nodes. This is not a good idea for a wider net for obvious reasons.

Re:Good till everyone has one...

[s.surfer]

Metricom's ricochet network used the mesh arrangment. It worked well, for the multi-city
network for that company. The mesh is designed to get around local problems within a large network,
ie. your local link died so you use the next closest link point.

mesh networks

[Unominous Coward]

A smart routing protocol for many-to-many wireless connections is critical for the growth of metropolitan wireless networks.

If anybody in Sydney, Australia is interested in joining a wireless network, check out Sydney Wireless.

The subject of "mesh networks" was covered in...

[Anonymous Coward]

...Wireless Business & Technology magazine recently, in the October 2002 issue--from the now especially timely perspective of how they will almost certainly feature in just the kind of "4G Battlefield" that we may be about to witness in Iraq.

In their WBT article "The Unwired soldier," authors Allen H. Kupetz and K. Terrell Brown introduce their concept of the 'Wal-Mart Soldier' and explain how "every soldier's communication device will be an individual network element with a unique IP address. All the network devices on the battlefield - including those embedded in tanks or other vehicles - will instantly form, heal, and update the network as users come and go. That is, they will associate in an ad hoc manner."

"But unlike cell-based solutions," the authors write, "network coverage and service levels will improve when soldier density increases. Network resources are also better utilized because networks are self-balancing as well. The soldier's subscriber device can hop to distant network access points, away from points of congestion, shifting network capacity to where the demand is."

Here's the really wild part, though: "Finally, this technology will function as a PAN (personal area network), a LAN (local area network), and a WAN (wide area network), simultaneously. This means that the same network can connect a soldier to the squad/platoon, to the battalion, and to a fully mobile division. This is critical to meeting the functionality requirements of the FCS program. It is the equivalent of Bluetooth, 802.11, and 3G converging, but in a single network, with a single device."

They also point out (before you ask!) that "The next-generation soldier's communication device has not yet been chosen. There are several DARPA/DoD projects operating simultaneously, all of which have a communications device component. These include the "Warfighter Information Network - Tactical" (WIN-T), "Future Combat Systems" (FCS - formerly known as Future Ground Combat Systems), "Small Unit Operations/Situational Awareness System" (SUO/SAS), and the "Joint Tactical Radio System - Programmable, Modular Communications System" (JTRS-PMCS)."

thats why Nokia killed their mesh products....

[Thorizdin]

Mesh wireless networks sound good in theory, kinda like microkernel OS's ;p, but in practice they have been unworkable to this point. Nokia bought a company, whose name I can't remember, for this type of product, Nokia called it Rooftop. The previous company had spent more than 4 years in development, and Nokia pumped in enough cash to add another year or so, but the product was a technical failure. Our company was already experienced deploying wireless systems (Alvarion/Breezecom and Orninoco) so we liked what Nokia had to say about the product and we gave it a try. The system proved to be totally unusable, the customer prem equipment often couldn't figure out which way to send traffic if the node it was previously using went away. I don't think that a mesh system is totally unworkable, but I do think its more complicated than most people think. Nokia has already removed the info from their site, but

google cache here

Tessco was Nokia's reseller on the line and they still have info and pics on it here

but still not effectively because...

[James_Duncan8181]

This assumes that the network does not have to connect to the outside world. If and when people want to read/post on slashdot etc, (You just know that one of the first actions would be someone irradiating the neighbourhood from the slashdot link to their server ;) you need to link up to a high bandwidth pipe, or the slashdot server itself (unlikely there is a link) now the network then has to coalese around the point where the bandwith to outside machines. The mesh needs to route the furthest away machines to this, and each hop increases the bandwidth used. In contested, quite limited spectrum. So even assuming no microwaves etc add to the fun, the network cannot function effectively unless many people share their bandwidth (must be varied locations, not just one big pipe). If you are in a situation where you can do this, there is obviously a lot of wired networks provided already, and the point of a mesh network disappears. If you are somewhere with few local links to a wired net, the mesh network has fundamental problems with contention and the total amount of spectrum availible for the high bandwith links.

you see?

All media, no mesh

[Anonymous Coward]

Having watched him operate for several years, it seems that Rob Poor thinks that simply by 1) talking about mesh networks for several years, 2) building a half-assed mesh simulator for his M.S. thesis that didn't even work, 3) blustering his way through a Ph.D. on the strength of that old simulator, 4) raising VC for an ill-posed attack on a very difficult problem, and 5) sitting on topic committees that have many fine lunches and dinners at consortium expense, he will somehow gain insight into a problem that he still doesn't even understand.

But if you really want to believe the hype, then perhaps you'll be impressed by the advanced level of technical sophistication evidenced by this presentation on his website. Don't forget your free sample of PIC code that shows us all how gosh-dang simple it is to be a radio engineer! Want to build a mesh? Just sprinkle a few thousand PICs in the environment and they'll self-organize into a network through the emergent properties of entrainment!

It seems so obvious; why didn't we think of that?