Startup Promotes Switchless Networks

A small UK startup is promoting a network architecture that could upset a lot of big equipment vendors if it's successful -- a bidirectional "bus" network that requires neither switches nor routers.

Called Pipistrelle Ltd. (Website still under construction), the company is still in its early stages. It's waiting for a technology license from Lockheed Martin Corp., which covers the basic architecture. Lockheed also intends to license the technology to a newly minted startup in Florida (name unknown) to cover the American market.

Lockheed developed the technology some time ago but didn't want to commercialize it for telecom networks, according to Pipistrelle's managing director Dick Winchester. And rather than give the idea to a company already in the communications business, it decided to encourage startups that would be solely focused on what it calls "fiber-optic bus wavelength division multiplexing" (FOBWDM).

The main feature of FOBWDM is that it's all optical, meaning that there are no electronics in the path of the data. That allows the core infrastructure of the network to be protocol- and data-rate-independent. Winchester claims that FOBWDM is suitable for speeds up to and including 40 Gbit/s.

Being a bus system, it means that the data does not need to be routed to a particular destination. It is broadcast through the system, and when it passes through the destination node, it gets recognized by the equipment and picked up. As a result, FOBWDM doesn't require switches or routers.

Instead, what's called an "optical bus interface module" (OBIM) is placed at each node in the network. This contains passive splitters that tap signals traveling on the network and place new signals into circulation.

An OBIM feeds signals into an interface card, which contains some kind of magic to ensure that all the signals on the network are kept up to strength optically. "You would think that the signal-to-noise ratio would worsen, but in fact it doesn't," notes Winchester. This observation was made on a demonstrator network built at Lockheed's plant in San Diego, he adds.

On a small scale, the FOBWDM idea has already proven itself. Lockheed has put the idea into practice as the communications nervous system inside two NP-3 testbed aircraft. However, putting communications systems comprising roughly 100 feet of cable into military aircraft is an entirely different thing from building a national or regional network covering hundreds of miles. Winchester claims that it would be possible to build a FOBWDM that covered the entire U.K. but can furnish little evidence to prove that it would work as advertised.

Pipistrelle also faces the not insignificant hurdle of convincing people to buy into a rather radical idea that would require drastic changes in their network infrastructures.

By its nature, the bus network is bidirectional -- signals travel in both directions along the fiber. That immediately rules out the possibility of using Erbium Doped-Fiber Amplifiers (EDFAs) in the network, since they contain isolators that only permit signals to pass in one direction. Therefore, most existing fiber plant is unsuitable for FOBWDM.

Other startups that have challenged mainstream technology, such as, for example, CodeStream Technologies with its OCDMA (optical code division multiple access) modulation scheme, have met with resistance, even though there may have been certain advantages to the technology (see CodeStream Goes Under).

Right now, Pipistrelle comprises only three people: Winchester and two others, whom he is not at liberty to name, since they haven't left their present employers. The company is registered at Insch in Aberdeenshire, Scotland, "where the air is clearer and houses are considerably cheaper." It remains to be seen if this batty idea will fly. The first task, apart from waiting for the license agreement, is to identify where the opportunities are for FOBWDM networks.

— Pauline Rigby, Senior Editor, Light Reading
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PhilMorrison99 12/4/2012 | 7:31:58 PM
re: Startup Promotes Switchless Networks Veemee,

Haven't the servers been the bottleneck for quite sometime now :) (then again look at BlueArc and what they are doing). There are pros and cons to any technology based solution, that said there is still much to learn about FOBWDM isn't there.

jim_smith 12/4/2012 | 7:31:57 PM
re: Startup Promotes Switchless Networks This startup has ONE employee. They don't even
have the technology license. I'd love to find out
who is funding them... wait a sec, do they have
funding yet?

I have a startup that builds airplanes with 1.5
wings and 13 engines. Starbucks is selling me
the technology license... I need two more
guys... any takers?
santosh1914 12/4/2012 | 7:31:57 PM
re: Startup Promotes Switchless Networks I have some opinions on this comment.
What we are discussing here is not about the specific company named Pipistrelle Ltd. and its ability to commercialize the technology of FOBWDM. What we are trying to find out is, does this approach to building optical network have a potential to reduce the highly expesive optical switches being produced and sold today. I do not think we need to be reminded again (after seeing so many service providers going out of business) that there is great need to reduce the expense of building and managing telecom networks if this industry really intends to make Video on Demand or Videophone, or Videoconferencing accessible to a common user.

FOBWDM may prove to be one way to reduce the capital expense of the carriers. If Pipistrelle Ltd can not commercialize this technology because it has one employee and no star VC backing it, some other startup or some established company can do that.

The real question is: Is FOBWDM a silver bullet for the telecom industry?

metroman 12/4/2012 | 7:31:56 PM
re: Startup Promotes Switchless Networks Santosh

At last a voice of reason.

I would like to add that there is a potential danger. If Pipistrelle get the licence for this technology then they will possibly have the key to Alladins cave.

I don't want to be a conspiracy theorist but I have been to Aberdeenshire and there are precious few reasons for anyone of any note in this industry to want to work there. In the UK most people in this industry are located in the South in and around London. London is 15 hours drive from Aberdeen with pretty poor air links.

If I was a US company with a nice idea that was a bit off the wall, what would I do? Tell the work that I was going to licence it to a guy in the middle of knowhere in Scotland and wait for the VC's to come knocking to say "don't be so silly, we'll give you $20million and we will give the idea to to a few redundant optical startup guys we know in Silicon Valley.

Why no licence yet?
Why no money yet?
Why no people yet?
Why are we talking about it?

We are all trying to guess what they are doing, by the time they get this productised, 40Gbps will be too slow anyway. VCs keep your money.

I may not seem to be a voice of reason, but I have been to Aberdeen KEEP YOUR MONEY.
DickW 12/4/2012 | 7:31:55 PM
re: Startup Promotes Switchless Networks Metroman... How extremely ill informed you are... Aberdeen is an ideal place to have this sort of start up.. The place is boiling over with skills as a consequence of 25 years of oil/gas industry.. There are probably more electronics and software people per sq foot here than anywhere else in the country.... Companies building everything from subsea control systems, digital video and sonars, remotely operated vehicles you name it....

It's also considerably cheaper to live here than the S of England - especially London - and strangely we tend not to drive to London but go by air and there's at least eight flights a day...

I also have to tell you that there already a plethora of optoelectronic companies in Scotland.. Kamelian, Kymata, Intense Photonics to name just a few.. We are also lucky enough to have some of the best universities with many rated highly for their optoelectronics work..

So I'm not sure when you were here last but self evidently you didn't absorb much of what was going on ... Anyway, this is supposed to be the era of it doesn't matter where you set up and work.. You remember the " Geography is History" thing ...

Oh and to answer your last point about 40Gb/s being too slow by the time this is productionised.. That's OK ... The 80Gb/s trial went like a dream thanks. If you want to go any quicker then tell the laser boys....
DickW 12/4/2012 | 7:31:55 PM
re: Startup Promotes Switchless Networks Santosh

E-mail me at [email protected]

DKP 12/4/2012 | 7:31:54 PM
re: Startup Promotes Switchless Networks
>An OBIM feeds signals into an interface card,
> which contains some kind of magic

That magic (my guess) requires tunable lasers and tunable detectors (or an array). This makes for a very expensive node. Also, star-splitters limit the distance to short distances. A good technology means nothing if it is not good market value. This reminds me of a PhD paper (or something Lockheed could afford to do), that looks cool, but that no one in the market is asking for.

boson3 12/4/2012 | 7:31:54 PM
re: Startup Promotes Switchless Networks By the time they get this productised, 40Gbps will be too slow anyway. VCs keep your money.

I think the story implied that the technology is bit rate independent.

That the company is in Aberdeen is irrelevant, Lockmart probably wanted to keep them away from the prying eyes of KPCB and company. LockMart's expertise in satellite and defense technologies is probably a liability, which is why they set up an arms-length entity.

The issue is whether LockMart's "Skunkworks II" can commercialize the product given their inexperience dealing with major carriers for the supply of terrestrial telecom equipment.

santosh1914 12/4/2012 | 7:31:49 PM
re: Startup Promotes Switchless Networks I believe it is possible to bring down the cost of the nodes by avoiding or reducing the use of tunable lasers and receivers by careful network design, taking into consideration the expected traffic pattern. (Compare it to today's opto-electronic OXCs, which have a large array of transmitters/receivers in addition to the switching matrix.)

As for the star splitters, I believe this is the area where innovation is needed (which may have been done by Lockheed). The interface card at a node should not incur high loss on the signal passing throgh it if it is not the intended recipient.

MadMark 12/4/2012 | 7:31:45 PM
re: Startup Promotes Switchless Networks Not much information in the article, and a lot of idle speculation on the message board...

However, a visit to the USPTO web site, and a quick search (an/(lockheed and martin) and OBIM) turns up two relevant patents: US5,898,801 (network) and US5,901,260 (interface module). No doubt these represent a less refined version of what is being proposed for commercialization, but they give a general picture.

These patents describe a system in which (contrary to the implications of the article) optical amplification is used in the form of distributed gain using shared pump sources injected at the ends of the bus. If you are prepared to have a lot of erbium-doped fiber in your network, this can produce "lossless" links, and the minimum SNR degradation.

The system disclosed also uses fixed receiver filters. Therefore tunable sources are required, as another poster has already speculated. The patent mentions temperature tuning of DFB lasers, but it seems doubtful that this would be the preferred technology today given recent advances in tunable lasers.

It's interesting technology, but there are many similar ideas floating around which allow fibers to be shared, and centralized switching to be avoided. The exact architecture is not as important as whether you can make it cheap and efficient enough to persuade people to accept something so radically different from (and incompatible with) their existing systems.

It's also always worth bearing in mind that there might be good reasons why other shared medium technologies (e.g. Ethernet) have evolved into switched technologies. I have heard people with a lot of experience in LAN technolgies argue that switches are good for switching, and transmission lines are good for transmission, and that the drive in the 70's and 80's to develop technologies (such as CSMA/CD, token ring, etc.) that attempt to combine the two functions to eliminate the switches was ultimately not successful.

The argument is often trotted out that getting rid of expensive switches must be a good thing. But history tells us that the switches generally get cheaper, whereas the inefficiencies and complexities of doing distributed switching (which is, in reality, what all these "switchless" technologies really do, in the guise of "access protocols") remain forever!

So what's different this time?
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