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Optical/IP

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
http://www.lightreading.com
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DickW 12/4/2012 | 7:31:15 PM
re: Startup Promotes Switchless Networks Not only do we eat them we breed them..In fact the Haggis season will soon be open .. The best way to hunt them is to find their tracks on a mountain and walk round anti clockwise. It's a well known fact that right legs of the Haggis are shorter than its left legs ( this applies equally to males and females).. Consequently when they see you and they try to turn round and run away they fall over and roll down the mountain where they are collected by teams of Haggis collectors.

Can't stop to discuss this any more I'm off to see the Loch Ness Monster.. She always pops up this time of year in order to ensure a full crop of tourists next year...

metroman 12/4/2012 | 7:31:26 PM
re: Startup Promotes Switchless Networks PM99

If you take care to read my comments you will note 2 things. 1, I am not bashing the oil and gas industry and 2, I am not bashing Scotland.

You will note that I don't have any knowledge of the Oil industry and therefore was unaware of the interesting link between this and the Optoelectronics industry as Dick subsequently explanined.

I mentioned that comparing the relative values of the region of Aberdeenshire with Scotland as a whole was perhaps not a fair comparison. Comparing Aberdeenshire with the rest of Europe/World for these skills brings a little better perspective. Scotland is hardly renowned for development of this kind of technology, making it a difficult place to get and retain people and investment. There is a natural reason for Oil and Gas companies to be there but there is not an inherent infrastructure to attract the best people in the optoelectronics industry.

Yes I started this conversation based on the limitations I saw above. If you did not like my presentation of the point then that's fine, it's your perogative.

If Scotland becomes the next Isreal or Silicon Valley then I will be as happy as the next man but it takes more than a good idea to do it. You need infrastructure, investment, communications and lots of good people.


I do not promote the messages of the company/companies that I represent on these boards. These are my own views, where I work and what I promote is not important here. For Dick it is important. You can call me Devils Advocate and as such if you can provide a strong argument for my comments not being correct I will treat them with respect. Just saying my points are bad is not the basis for a discussion.

Metroman
DickW 12/4/2012 | 7:31:30 PM
re: Startup Promotes Switchless Networks I'm sorry metroman but you're into philosophy now and I haven't done the course... Like a lot of people who live in Scotland we tend to be not neccessarily defensive but perhaps eager....

As to why is it cheaper to live here then the answer is actually the reverse of what u suggest... In reality places like London and its surrounding aread have become overpriced in most senses because they have become overcrowded.. So as well as being expensive they are unpleasant unless you're a tourist of course..

There is actually a slow drift away from the SE of England as companies recognise that their costs are considerably higher and actually there isn't a great deal of benefit to be gained from being there..

I'm not quite sure what to make of your comments on the oil/gas industry.... Ever heard of companies such as Schlumberger? Go and imply to them that they are not highly skilled in most areas of electronics, opto-electronics, software and computing and you will get an appropriate response.. There is a just a little more to the industry than big chunks of mechanical hardware.. One of the major oil cos over here has just tied in all its offshore platforms with fibre and is looking at some very sophisticated networks covering not just comms and standard network services but process control data/control, well data sensors and a host of other applications.

I think if you took the time to look you would be very pleasantly surprised by some of the developments and the wide range of technologies.

switchrus 12/4/2012 | 7:31:30 PM
re: Startup Promotes Switchless Networks On Scotland, not to stoke the flames too muchGǪ:)

WhatGÇÖs the deal with Haggis? Do you really eat that stuff? LOL :)

For those who would like to read more about this Scottish delicacy:
http://www.smart.net/~tak/hagg...

Cheers! Court Jester

PhilMorrison99 12/4/2012 | 7:31:30 PM
re: Startup Promotes Switchless Networks Hey Metroman,

Why not concentrate on technology and its applicability or lack thereof. I'm not sure what kind of a service you think you are rendering by bashing an industry (oil & gas), as well as bashing a country (Scotland). If you go back a few emails I think you will notice that you launched the first attack. Are people expected to site still and just take that kind of sarcasm. Note Dick isn't hidding behind some fairy tale nickname is he. You know who he is and what he promotes, as well as where he is from. You on the other hand just sit back in the shadows and criticize, shame.

Flame away Metromouse!!

Phil..
DickW 12/4/2012 | 7:31:31 PM
re: Startup Promotes Switchless Networks No sorry... no relation as far as I'm aware.. My medical skills are strictly limited to hangover cures....
metroman 12/4/2012 | 7:31:35 PM
re: Startup Promotes Switchless Networks Dick

I have a few comments about your response to my comments.

I am sure all of those oil and gas skills will be great???

I assume that you are talking about Scotland when you mention the number of electronics and software people per square foot. I am sure Aberdeen does come out top, in a region that is relatively weak. WRT The companies you mention that are obviously building gear for the oil industry see the comment above.

Why is it considerably cheaper to live there? Tell me a place in the world where it is cheap to live and attracts the best people in any industry? Supply and demand, it's the same the world over! If well paid, well respected people wanted to live there the prices would not be low. People are prepared to pay the prices in London because they are compensated appropriately and they are at the hub of the action.

None of the organisations you mention (kymata etc) are what could be regarded as world leaders, which I assume is your target. And when they have the ability to become world leaders where will they be based? Aberdeen? hmmmm try selling that to an investor. It's a simple question of scale and skills. I agree that perhaps Aberdeen is a nice place to hibernate a neat idea but not to build a world beating business. You would fill all 8 of those prop planes to London every day, but then where would all the oil and gas people sit.

Geography is History is a great phrase to pull out of the bag. Sept. 11th aside more people are flying and travelling on business than ever. Why? Because technology does not yet answer the problem os the need for face to face meetings. Do you have a paperless office as well?

Well done on the 80Gig trial. I take that one back.

Lastly, you have an interesting way of presenting yourself to the outside world. Coming out fighting at the slightest criticism sounds a bit defensive to me.
UncleLeo 12/4/2012 | 7:31:40 PM
re: Startup Promotes Switchless Networks Dick,

Any relation to the famous throasic sugeon from Boston, Charles Emerson Winchester?

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?
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.

-Santosh
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