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
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.

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:

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!!

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.

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.

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]

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.
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?

santosh1914 12/4/2012 | 7:31:58 PM
re: Startup Promotes Switchless Networks Hi Dick,
Can you throw some light on what is the difference between a SONET ring opened up to look like a bus and the FOBWDM? Why should someone deploying a SONET Ring today consider FOBWDM as an alternative? I see the following points:

Let us call the SONET as switched approach and FOBWDM as switchless approach to building WDM networks on a bus topology.
1. Both approach will use same amount of fiber.
2. The switchless version (FOBWDM) will cost less.
3. The switchless version will need less number of amplifiers for the same distance or receivers with less sensitivity and/or transmitters with less power.
4. Now let us compare their scalability: Let us assume there is one pair of fiber in the bus with 40 lambdas. Let us devote 1 to control channel. The maximum number of connections that can be established in the switched version of the network will be (n-1)*39 where n is the number of switches. In the switchless version the maximum number of connections that can be established in the entire network will be 39 irrespective of the number of nodes in the network and these 39 connections will be shared by all the nodes. This is because increasing the broadcast domain reduces the wavelength (or more generally channel) reuse. So, as we increase the number of nodes in both versions of the network we can see that the number of connections that can be established per node reduces drastically ( (n-1)*39/n in the switched network vs 39/n in the switchless version). This is what I was referring to as scalability issues.

Santosh Kumar
Ohio State University
PhilMorrison99 12/4/2012 | 7:31:58 PM
re: Startup Promotes Switchless Networks That reminds me of a similar story about another couple who used to have "lot's of fun" in their garage. The eventually formed a company called cisco or should I say Cisco :-).
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.

yikes_stripes 12/4/2012 | 7:31:59 PM
re: Startup Promotes Switchless Networks The MIL STD 1773 bus was being looked at for possible expansion into the WDM realm at a place I worked at a while ago. There is alot of COTS available for this stuff. Just rip out the LED and put in an ITU laser and away you go. Lot's of fun in your garage.
veemee 12/4/2012 | 7:32:01 PM
re: Startup Promotes Switchless Networks Also there are going to be a limitations. The server will be a bottleneck. (Servers that allocate bandwidth to a particualr session, if things are not going to be CSMA/CD)
giles0 12/4/2012 | 7:32:02 PM
re: Startup Promotes Switchless Networks "Giles first... FOBWDM does not suffer from Ethernet style collisions..."

so can I assume from this that you don't dedicate a wavelength to each receiver?

do you then dedicate one to each transmitter - or is it something more complex?

If the former then I can't see how you'd scale to 1200 nodes?
santosh1914 12/4/2012 | 7:32:05 PM
re: Startup Promotes Switchless Networks The idea of a fiber bus seems interesting. Its lot like Ethernet with few differences, those due to the availablility of multiple independent wavelengths. Here is one way this network may work :
The data-transparency in optical network is due to the fact that a switch can connect an input port to an outport by looking at the wavelength only. The cross-connect state for a particular state is decided in advance through signaling. In FOBWDM also one channel can be devoted to exchanging signaling messages. This channel may be used to decide which pair of transmitter and receiver or a number of receivers (in case of multicast) will use a particular wavelength. The transmitter will have to check for all the free wavelengths on which it is capable of transmitting and then reserve a wavelength that the receiver(s) can receive on. The transmitter and receiver(s) will have agree on a common framing type.
Please note that the above scheme does not involve a CSMA/CD like mechanism except on the signaling channel. Its possible to use a scheme like CSMA/CD on data channels also but will be more complex.
Any more ideas or comments on above?
Its more improtant to find out its benefits w.r.t existing network topologies than figuring out how this may work. Here are my views:
1. This will use less fiber.
2. There is no need for a switching device. We still need mux/demux and amplifiers. So, there is sigificant cost savings given the high cost of optical switches.
3. The optical signals will incur less loss since they do not have to pass through a switching device.

1. The scalability is a big issue because the bandwidth is being shared among all nodes on the bus. As the number of nodes increase on the bus the number of connections that can be established per node will decrease. Increasing fibers on the bus will cause the number of transceivers to increase at the nodes. So, we may seem its application in networks of limited size (of the order of tens). The need of switches will still be there.
2. Reliability is a big issue unless we use SONET like protection mechanism of devoting half the bandwidth for protection.

DickW 12/4/2012 | 7:32:05 PM
re: Startup Promotes Switchless Networks Hi

Giles first... FOBWDM does not suffer from Ethernet style collisions...

Santosh ..... Your "advantages" points are pretty much spot on but there are others..

Your "disadvantages" are way off beam though.. The scaleability of the technology is much larger than you suggest.. certainly up to about 1200 "nodes" and perhaps greater.. AND, I can assure you only need a switch if you have to connect to the outside world... As far as reliability is concerned there is no need for the sort of protection you suggest..

[email protected]
giles0 12/4/2012 | 7:32:05 PM
re: Startup Promotes Switchless Networks Isn't this a subset of what George Gilder was talking about 9 years ago in "The Coming of the Fibersphere"?

"You can send all messages everywhere in the network, include all needed codes and instructions for correcting, decrypting, and reading them, and allow each terminal to tune into its own messages on its own wavelength, just like a two-way radio. When the terminals are smart enough and the bandwidth great enough, your all optical network can be as dumb as a stone."

a nice idea - but maybe a wee bit utopian? ;-)

From the name of the technology (which has WDM in it) I get the impression that Pipistrelle would assign each device a dedicated wavelength to receive on or to transmit on? The former would presumably require tunable lasers in the transmitting nodes and would potentially suffer from Ethernet-style collisions, whilst the latter would require a node to listen to all frequencies simultaneously?

anyone got any better idea as to how this might work?

Pseudopersonality 12/4/2012 | 7:32:06 PM
re: Startup Promotes Switchless Networks This idea is screaming out for a startup to figure out!

Looks like a local area network possibility like an...aircraft.

Have fun
brian.murray 12/4/2012 | 11:06:36 PM
re: Startup Promotes Switchless Networks
out of curiousity metroman ... where in the UK do you see as being the hive(s) of the the fibre related industry?
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