Ovum Q&A: Infinera as an end-to-end systems vendor
Infinera hosted an Insight analyst day on October 6th to highlight its plans now that it has acquired metro equipment player, Transmode. Gazettabyte interviewed Ron Kline, principal analyst, intelligent networks at market research firm, Ovum, who attended the event.
Q. Infinera’s CEO Tom Fallon referred to this period as a once-in-a-decade transition as metro moves from 10 Gig to 100 Gig. The growth is attributed mainly to the uptake of cloud services and he expects this transition to last for a while. Is this Ovum’s take?
Ron Kline, OvumRK: It is a transition but it is more about coherent technology rather than 10 Gig to 100 Gig. Coherent enables that higher-speed change which is required because of the level of bandwidth going on in the metro.
We are going to see metro change from 10 Gig to 100 Gig, much like we saw it change from 2.5 Gig to 10 Gig. Economically, it is going to be more feasible for operators to deploy 100 Gig and get more bang for their buck.
Ten years is always a good number from any transition. If you look at SONET/SDH, it began in the early 1990s and by 2000 was mainstream.
If you look at transitions, you had a ten-year time lag to get from 2.5 Gig to 10 Gig and you had another ten years for the development of 40 Gig, although that was impacted by the optical bubble and the [2008] financial crisis. But when coherent came around, you had a three-year cycle for 100 gigabit. Now you are in the same three-year cycle for 200 and 400 gigabit.
Is 100 Gig the unit of currency? I think all logic tells us it is. But I’m not sure that ends up being the story here.
If you get line systems that are truly open then optical networking becomes commodity-based transponders - the white box phenomenon - then where is the differentiation? It moves into the software realm and that becomes a much more important differentiator.
Infinera’s CEO asserted that technology differentiation has never been more important in this industry. Is this true or only for certain platforms such as for optical networking and core routers?
If you look at Infinera, you would say their chief differentiator is the PIC (photonic integrated circuit) as it has enabled them to do very well. But other players really have not tried it. Huawei does a little but only in the metro and access.
It is true that you need differentiation, particularly for something as specialised as optical networking. The edge has always gone to the company that can innovate quickest. That is how Nortel did it; they were first with 10 gigabit for long haul and dominated the market.
When you look at coherent, the edge has gone to the quickest: Ciena, Alcatel-Lucent, Huawei and to a certain extent Infinera. Then you throw in the PIC and that gives Infinera an edge.
But then, on the flip side, there is this notion of disaggregation. Nobody likes to say it but it is the commoditisation of the technology; that is certainly the way the content providers are going.
If you get line systems that are truly open then optical networking becomes commodity-based transponders - the white box phenomenon - then where is the differentiation? It moves into the software realm and that becomes a much more important differentiator.
I do think differentiation is important; it always is. But I’m not sure how long your advantage is these days.
Infinera argues that the acquisition of Transmode will triple the total available market it can address.
Infinera definitely increases its total available market. They only had an addressable market related to long haul and submarine line terminating equipment. Now this [acquisition of Transmode] really opens the door. They can do metro, access, mobile backhaul; they can do a lot of different things.
We don’t necessarily agree with the numbers, though, it more a doubling of the addressable market.
The rolling annual long-haul backbone global market (3Q 2014 to 2Q 2015) and the submarine line terminating equipment market where they play [pre-Transmode] was $5.2 billion. If you assume the total market of $14.2 billion is addressable then yes it is nearly a tripling but that includes the legacy SONET/SDH and Bandwidth Management segments which are rapidly declining. Nevertheless, Tom’s point is well-taken, adding a further $5.8 billion for the metro and access WDM markets to their total addressable market is significant.
Tom Fallon also said vendor consolidation will continue, and companies will need to have scale because of the very large amounts of R&D needed to drive differentiation. Is scale needed for a greater R&D spend to stay ahead of the competition?
When you respond to an operator’s request-for-proposal, that is where having end-to-end scale helps Infinera; being able to be a one-stop shop for the metro and long haul.
If I’m an operator, I don’t have to get products from several vendors and be the systems integrator.
Infinera announced a new platform for long haul, the XT-500, which is described as a telecom version of its data centre interconnect Cloud Xpress platform. Why do service providers want such a platform, and how does it differ from cloud Xpress?
Infinera’s DTN-X long haul platform is very high capacity and there are applications where you don’t need a such a large platform. That is one application.
The other is where you lease space [to house your equipment]. If I am going to lease space, if I have a box that is 2 RU (rack unit) high and can do 500 gigabit point-to-point and I don’t need any cross-connect, then this smaller shelf size makes a lot of sense. I’m just transporting bandwidth.
Cloud Xpress is a scaled-down product for the metro. The XT-500 is carrier-class, e.g. NEBS [Network Equipment-Building System] compliant and can span long-haul distances.
Infinera has also announced the XTC-2. What is the main purpose of this platform?
The platform is a smaller DTN-X variant to serve smaller regions. For example you can take a 500 gigabit PIC super-channel and slice it up. That enables you to do a hub-and-spoke virtual ring and drop 100 Gig wavelengths at appropriate places. The system uses the new metro PICs introduced in March. At the hub location you use an ePIC that slices up the 500G into individually routable 100G channels and at the hub location, where the XTC-2 is, you use an oPIC-100.
Does the oPIC-100 offer any advantage compared to existing100 Gig optics?
I don’t think it has a huge edge other than the differentiation you get from a PIC. In fact it might be a deterrent: you have to buy it from Infinera. It is also anti-trend, where the trend is pluggables.
But the hub and spoke architecture is innovative and it will be interesting to see what they do with the integration of PIC technology in Transmode’s gear.
Acquiring Transmode provides Infinera with an end-to-end networking portfolio? Does it still lack important elements? For example, Ciena acquired Cyan and gained its Blue Planet SDN software.
Transmode has a lot of different technologies required in the metro: mobile back-haul, synchronisation, they are also working on mobile front-hauling, and their hardware is low power.
Transmode has pretty much everything you need in these smaller platforms. But it is the software piece that they don’t have. Infinera has a strategy that says: we are not going to do this; we are going to be open and others can come in through an interface essentially and run our equipment.
That will certainly work.
But if you take a long view that says that in future technology will be commoditised, then you are in a bad spot because all the value moves to the software and you, as a company, are not investing and driving that software. So, this could be a huge problem going forward.
What are the main challenges Infinera faces?
One challenge, as mentioned, is hardware commoditisation and the issue of software.
Hardware commodity can play in Infinera’s favour. Infinera should have the lowest-cost solution given its integrated solution, so large hardware volumes is good for them. But if pluggable optics is a requirement, then they could be in trouble with this strategy
The other is keeping up with the Joneses.
I think the 500 Gig in 100 Gig channels is now not that exciting. The 500 Gig PIC is not creating as much advantage as it did before. Where is the 1.2 terabit PIC? Where is the next version that drives Infinera forward?
And is it still going to be 100 Gig? They are leading me to believe it won’t just be. Are they going to have a PIC that is 12 channels that are tunable in modulation formats to go from 100 to 200 to 400 Gig.
They need to if they want to stay competitive with everyone else because the market is moving to 200 Gig and 400 Gig. Our figures show that over 2,000 multi-rate (QPSK and 16-QAM) ports have been shipped in the last year (3Q 2014 to 2Q 2015). And now you have 8-QAM coming. Infinera’s PIC is going to have to support this.
Infinera’s edge is the PIC but if you don’t keep progressing the PIC, it is no longer an edge.
These are the challenges facing Infinera and it is not that easy to do these things.
Business services and mobile revive WDM-PON interest
"WDM-PON is many things to many people" - Jon Baldry
It was in 2005 that Novera Optics, a pioneer of WDM-PON (wavelength-division multiplexing, passive optical networking), was working with Korea Telecom in a trial involving 50,000 residential lines. Yet, one decade later, WDM-PON remains an emerging technology. And when a WDM-PON deployment does occur, it is for business services and mobile backhaul rather than residential broadband.
WDM-PON delivers high-capacity, symmetrical links using a dedicated wavelength. The links are also secure, an important consideration for businesses, and in contrast to PON where data is shared between all the end points, each selecting its addressed data.
One issue hindering the uptake of WDM-PON is the lack of a common specification. "WDM-PON is many things to many people," says Jon Baldry, technical marketing director at Transmode.
One view of WDM-PON is as the ultimate broadband technology; this was Novera's vision. Other vendors, such as Transmode, emphasise the WDM component of the technology, seeing it as a way to push metro-style networking towards the network edge, to increase bandwidth and for operational simplicity.
WDM-PON's uptake for residential access has not yet happened because the high bandwidth it offers is still not needed, while the system economics do not match those of PON.
Gigabit PON (GPON) and Ethernet PON (EPON) are now deployed in the tens of millions worldwide. And operators can turn to 10G-EPON and XG-PON when the bandwidth of GPON and EPON are insufficient. Beyond that, TWDM-PON (Time and Wavelength Division Multiplexing PON) is an emerging approach, promoted by the likes of Alcatel-Lucent and Huawei. TWDM-PON uses wavelength-division multiplexing as a way to scale PON, effectively supporting multiple 10 Gigabit PONs, each riding on a wavelength.
Carriers like the reassurance a technology roadmap such as PON's provides, but their broadband priority is wireless rather than wireline. The bigger portion of their spending is on rolling out LTE since wireless is their revenue earner.
As for fixed broadband, operators are being creative.
G.fast is one fixed broadband example. G.fast is the latest DSL standard that supports gigabit speeds over telephone wire. Using G.fast, operators can combine fibre and DSL to achieve gigabit rates and avoid the expense of taking fibre all the way to the home. BT is one operator backing G.fast, with pilot schemes scheduled for the summer. And if the trials are successful, G.fast deployments could start next year.
Deutsche Telekom is promoting a hybrid router to customers that combines fixed and wireless broadband, with LTE broadband kicking in when the DSL line becomes loaded.
Meanwhile, vendors with a WDM background see WDM-PON as a promising way to deliver high-volume business services, while also benefiting from the operator's cellular push by supporting mobile backhaul and mobile fronthaul. They don't dismiss WDM-PON for residential broadband but accept that the technology must first mature.
Transmode announced recently its first public customer, US operator RST Global Communications, which is using the vendor's iWDM-PON platform for business services.
"Our primary focus is business and mobile backhaul, and we are pushing WDM deeper into access networks," says Baldry. "We don't want a closed network where we treat WDM-PON differently to the way we treat the rest of the network." This means using the C-band wavelength grid for metro and WDM-PON. This avoids having to use optical-electrical-optical translation, as required between PON and WDM networks, says Baldry.
The iWDM-PON system showing the seeder light source at the central office (CO) optical line terminal (OLT), and the multiplexer (MDU) that selects the individual light band for the end point customer premise equipment (CPE). Source: Transmode.
Transmode's iWDM-PON
Several schemes are being pursued to implement WDM-PON. One approach is seeded or self-tuning, where a broadband light source is transmitted down the fibre from the central office. An optical multiplexer is then used to pick off narrow bands of the light, each a seeder source to set the individual wavelength of each end point optical transceiver. An alternative approach is to use a tunable laser transceiver to set the upstream wavelength. A third scheme combines the broadband light source concept with coherent technology that picks off each transceiver's wavelength. The coherent approach promises extremely dense, 1,000 wavelength WDM-PONs.
Transmode has chosen the seeded scheme for the iWDM-PON platform. The system delivers 40, 1 Gigabit-per-second (Gbps) wavelengths spaced 50 GHz apart. The reach between the WDM-PON optical line terminal (OLT) and the optical network unit (ONU) end-points is 20 km without dispersion compensation fibre, or 30 km using such fibre. The platform uses WDM-PON SFP pluggable modules. The SFPs are MSA-compliant and use a fabry-perot laser and an avalanche photo-detector optimised for the injection-locked signal.
"We use the C-band and pluggable optics, so the choice of using WDM-PON optics or not is up to the customer," says Baldry. "It should not be a complicated decision, and the system should work seamlessly with everything else you do, enabling a mix of WDM-PON and regular higher speed or longer reach WDM over the same access network, as needed."
Baldry claims the approach has economic advantages as well as operational benefits. While there is a need for a broadband light source, the end point SFP WDM-PON transceivers are cheaper compared to fixed or tunable optics. Also setting the wavelengths is automated; the engineers do not need to set and lock the wavelength as they do using a tunable laser.
"The real advantage is operational simplicity," says Baldry, especially when an operator needs to scale optically connected end-points as they grow business and mobile backhaul services. "That is the intention of a PON-like network; if you are ramping up the end points then you have to think of the skill levels of the installation crews as you move to higher service volumes," he says.
RST Global Communications uses Transmode's Carrier Ethernet 2.0 as the service layer between the demarcation device (network interface device or NID) at the customer's premises, while using Transmode's packet-optical cards in the central office. WDM-PON provides the optical layer linking the two.
An early customer application for RST was upgrading a hotel's business connection from a few megabits to 1Gbps to carry Wi-Fi traffic in advance of a major conference it was hosting.
Overall, Transmode has a small number of operators deploying the iWDM-PON, with more testing or trialing it, says Baldry. The operators are interested in using the WDM-PON platform for mobile backhaul, mobile fronthaul and business services.
There are also operators that use installed access/ customer premise equipment from other vendors, exploring whether Transmode's WDM-PON platform can simplify the optical layer in their access networks.
Further developments
Transmode's iWDM-PON upgrade plans include moving the system from a two fibre design - one for the downstream traffic and one for the upstream traffic - to a single fibre one. To do this, the vendor will segment the C-band into two: half the C-band for the uplink and half for the downlink.
Another system requirement is to increase the data rate carried by each wavelength beyond a gigabit. Mobile fronthaul uses the Common Public Radio Interface (CPRI) standard to connect the remote radio head unit that typically resides on the antenna and the baseband unit.
CPRI data rates are multiples of the basic rate of 614.4 Mbps. As such 3 Gbps, 6 Gbps and rates over 10 Gbps are used. Baldry says the current iWDM-PON system can be extended beyond 1 Gbps to 2.5 Gbps and potentially 3 Gbps but because the system in noise-limited, the seeder light scheme will not stretch to 10 Gbps. A different optical scheme will be needed for 10 Gigabit. The iWDM-PON's passive infrastructure will allow for an in-service upgrade to 10 Gigabit WDM-PON technology once it becomes technically and economically viable.
Transmode has already conducted mobile fronthaul field trials in Russia and in Asia, and lab trials in Europe, using standard active and passive WDM and covering the necessary CPRI rates. "We are not mixing it with WDM-PON just yet; that is the next step," says Baldry.
Further information
WDM-PON Forum, click here
Lightwave Magazine: WDM-PON is a key component in next generation access
Transmode adopts 100 Gigabit coherent CFPs
Transmode has detailed line cards that bring 100 Gigabit coherent CFP optical modules to its packet optical transport platforms.
We can be quicker to market when newer DSP-based CFPs appear
Jon Baldry
"We believe we are the first to market with line-side coherent CFPs, bringing pluggable line-side optics to a WDM portfolio," says Jon Baldry, technical marketing director at Transmode. Baldry says that other system vendors already support non-coherent CFP modules on their line cards and that further vendor announcements using coherent CFPs are to be expected.
The Swedish system vendor announced three line cards: a 100 Gig transponder, a 100 Gig muxponder and what it calls its Ethernet muxponder (EMXP) card. The first two cards support wavelength division multiplexing (WDM) Layer 1 transport: the 100 Gig transponder card supports two 100 Gig CFP modules while the 100 Gig muxponder supports 10x10 Gig ports and a CFP.
The third card, the EMXP220/IIe, has a capacity of 220 Gig: 12x10 Gigabit Ethernet ports and the CFP, with all 13 ports supporting optional Optical Transport Network (OTN) framing. "You can think of it as a Layer 2 switch on a card with 13 embedded transponders," says Baldry. The three cards each take up two line card slots.
Transmode's platforms are used for metro and metro regional networks. Metro has more demanding cost, space and power efficiency requirements than long distance core networks. "The move that the whole industry is taking to CFP or pluggable-based optics is a big step forward [in meeting metro's requirements]," says Baldry.
The line cards will be used with Transmode's metro edge TM-Series packet optical family that is suited for applications such as mobile backhaul and business services. "Within packet-optical networks, we can do customer premise Gigabit Ethernet all the way through to 100 Gig handover to the core on the same family of cards running the same Layer 2 software," says Baldry. Transmode believes this capability is unique in the industry.
The TM-3000 chassis is 11 rack units (RU) high and can hold eight double-slot cards, for a total of 800 Gig CFP line side capacity.
Source: Transmode
100 Gig coherent modules
Transmode is talking to several 100 Gig coherent CFP module makers. The company will use multiple suppliers but says it is currently working with one manufacturer whose product is closer to market.
Acacia Communications announced the first CFP module late last year and other module makers are expected to follow at the upcoming OFC show in March 2014.
The roadmap of the CFP modules envisages the CFP to be followed by the smaller CFP2 and smaller still CFP4. For the CFP2 and CFP4, the coherent digital signal processor (DSP) ASIC is expected to be external to the module's optics, residing on the line card instead. The 100 Gig CFP, however, integrates the DSP-ASIC within the module and this approach is favoured by Transmode.
"We can be quicker to market when newer DSP-based CFPs appear; today we can do 800km and in the future that will go to a longer reach or lower power consumption," says Baldry. "Also, the same port can take a coherent CFP or a 100BASE-SR4 or -LR4 CFP without having the cost burden of a DSP on the card whether it is needed or not."
The company also points out that by using the integrated CFP it can choose from all the coherent designs available whereas modules that separate the optics and DSP-ASIC will inevitably offer a more limited choice.
There are also 100 Gigabit direct detection CFPs from the likes of Finisar and Oplink Communications and Transmode's cards would support such a CFP module. But for now the company says its main interest is in coherent.
"One key requirement for anything we deploy is that it works with the existing optical infrastructure," says Baldry. "One difference between 100 Gig metro and long haul is that a lot of the long distance 100 Gig is new build, whereas the metro will require 100 Gig over existing infrastructure and coherent works very nicely with the existing design rules and existing 10 Gig networks."
The 100 Gig transponder card consumes 75W, with the coherent CFP accounting for 30W of the total. The card can be used for signal regeneration, hosting two 100 Gig coherent CFPs rather than the more typical arrangement of a client-side and a line-side CFP. The card's power consumption exceeds 75W, however, when two coherent CFPs are used.
The 100 Gig transponder and Ethernet muxponder will be available in the second quarter of 2014, says Transmode, while the 100 Gig muxponder card will follow early in the third quarter of the year.
Books in 2013 - Part 1
Gazettabyte is asking various industry figures to highlight books they have read this year and recommend, both work-related and more general titles.
Part 1:
Tiejun J. Xia (TJ), Distinguished Member of Technical Staff, Verizon
The work-related title is Optical Fiber Telecommunications, Sixth Edition, by Ivan Kaminow, Tingye Li and Alan E. Willner. This edition, published in 2013, includes almost all the latest development results of optical fibre communications.
My non-work-related book is Fortune: Secrets of Greatness by the editors of Fortune Magazine. While published in 2006, the book still sheds light on the 'secrets' of people with significant accomplishments.
Christopher N. (Nick) Del Regno, Fellow Verizon
OpenStack Cloud Computing Cookbook, by Kevin Jackson is my work-related title. While we were in the throes of interviewing candidates for our open Cloud product development positions, I figured I had better bone up on some of the technologies.
One of those was OpenStack’s Cloud Computing software. I had seen recommendations for this book and after reading it and using it, I agree. It is a good 'OpenStack for Dummies' book which walks one through quickly setting up an OpenStack-based cloud computing environment. Further, since this is more of a tutorial book, it rightly assumes that the reader would be using some lower-level virtualisation environment (e.g., VirtualBox, etc) in which to run the OpenStack Hypervisor and virtual machines, which makes single-system simulation of a data centre environment even easier.
Lastly, the fact that it is available as a Kindle edition means it can be referenced in a variety of ways in various physical locales. While this book would work for those interested in learning more about OpenStack and virtualisation, it is better suited to those of us who like to get our hands dirty.
My somewhat work-related suggestions include Brilliant Blunders: From Darwin to Einstein – Colossal Mistakes by Great Scientists That Changed Our Understanding of Life and the Universe, by Mario Livio.
I discovered this book while watching Livio’s interview on The Daily Show. I was intrigued by the subject matter, since many of the major discoveries over the past few centuries were accidental (e.g. penicillin, radioactivity, semiconductors, etc). However, this book's focus is on the major mistakes made by some of the greatest minds in history: Darwin, Lord Kelvin, Pauling, Hoyle and Einstein.
It is interesting to consider how often pride unnecessarily blinded some of these scientists to contradictions to their own work. Further, this book reinforces my belief of the importance of collaboration and friendly competition. So many key discoveries have been made throughout history when two seemingly unrelated disciplines compare notes.
Another is Beyond the Black Box: The Forensics of Airplane Crashes, by George Bibel. As a frequent flyer and an aviation buff since childhood, I have always been intrigued by the process of accident investigation. This book offers a good exploration of the crash investigation process, with many case studies of various causes. The book explores the science of the causes and the improvements resulting from various accidents and related investigations. From the use of rounded openings in the skin (as opposed to square windows) to high-temperature alloys in the engines to ways to mitigate the impact of crash forces on the human body, the book is a fascinating journey through the lessons learned and the steps to avoid future lessons.
While enumerating the ways a plane could fail might dissuade some from flying, I found the book reassuring. The application of the scientific method to identifying the cause of, and solution to, airplane crashes has made air travel incredibly safe. In exploring the advances, I’m amazed at the bravery and temerity of early air travelers.
Outside work, my reading includes Doctor Sleep, by Stephen King. The sequel to “The Shining” following the little boy (Dan Torrence) as an adult and Dan’s role-reversal now as the protective mentor of a young child with powerful shining.
I also recommend Joyland (Hard Case Crime), by Stephen King. King tries his hand at writing a hard-case crime novel with great results. Not your typical King…think Stand by Me, Hearts in Atlantis, Shawshank Redemption.
Andrew Schmitt, Principal Analyst, Optical at Infonetics Research
My work-related reading is Research at Google.
Very little signal comes out of Google on what they are doing and what they are buying. But this web page summarises public technical disclosures and has good detail on what they have done.
There are a lot of pretenders in the analyst community who think they know the size and scale of Google's data center business but the reality is this company is sealed up tight in terms of disclosure. I put something together back in 2007 that tried to size 10GbE consumption (5,000 10GbE ports a month ) but am the first to admit that getting a handle on the magnitude of their optical networking and enterprise networking business today is a challenge.
Another offending area is software-defined networking (SDN). Pundits like to talk about SDN and how Google implemented the technology in their wide area network but I would wager few have read the documents detailing how it was done. As a result, many people mistakenly assume that because Google did it in their network, other carriers can do the same thing - which is totally false. The paper on their B4 network shows the degree of control and customisation (that few others have) required for its implementation.
I also have to plug a Transmode book on packet-optical networks. It does a really good job of defining what is a widely abused marketing term, but I’m a little biased as I wrote the forward. It should be released soon.
The non-work-related reading include Nate Silver’s book: The Signal and the Noise: Why So Many Predictions Fail — but Some Don't . I am enjoying it. I think he approaches the work of analysis the right way. I’m only halfway through but it is a good read so far. The description on Amazon summarises it well.
But some very important books that shaped my thinking are from Nassim Taleb . Fooled by Randomness is by far the best read and most approachable. If you like that then go for The Black Swan. Both are excellent and do a fantastic job of outlining the cognitive biases that can result in poor outcomes. It is philosophy for engineers and you should stop taking market advice from anyone who hasn’t read at least one.
The Steve Jobs biography by Walter Isaacson was widely popular and rightfully so.
A Thread Across the Ocean is a great book about the first trans-Atlantic cable, but that is a great book only for inside folks – don’t talk about it with people outside the industry or you’ll be marked as a nerd.
If you are into crazy infrastructure projects try Colossus about the Hoover Dam and The Path Between the Seas about the Panama Canal. The latter discloses interesting facts like how an entire graduating class of French engineers died trying to build it – no joke.
Lastly, I have to disclose an affinity for some favourite fiction: Brave New World, by Aldous Huxley and The Fountainhead by Ayn Rand.
I could go on.
If anyone reading this likes these books and has more ideas please let me know!
Books in 2013 - Part 2, click here
Merits and challenges of optical transmission at 64 Gbaud
u2t Photonics announced recently a balanced detector that supports 64Gbaud. This promises coherent transmission systems with double the data rate. But even if the remaining components - the modulator and DSP-ASIC capable of operating at 64Gbaud - were available, would such an approach make sense?
Gazettabyte asked system vendors Transmode and Ciena for their views.
Transmode:
Transmode points out that 100 Gigabit dual-polarisation, quadrature phase-shift keying (DP-QPSK) using coherent detection has several attractive characteristics as a modulation format.
It can be used in the same grid as 10 Gigabit-per-second (Gbps) and 40Gbps signals in the C-band. It also has a similar reach as 10Gbps by achieving a comparable optical signal-to-noise ratio (OSNR). Moreover, it has superior tolerance to chromatic dispersion and polarisation mode dispersion (PMD), enabling easier network design, especially with meshed networking.
The IEEE has started work standardising the follow-on speed of 400 Gigabit. "This is a reasonable step since it will be possible to design optical transmission systems at 400 Gig with reasonable performance and cost," says Ulf Persson, director of network architecture in Transmode's CTO office.
Moving to 100Gbps was a large technology jump that involved advanced technologies such as high-speed analogue-to-digital (A/D) converters and advanced digital signal processing, says Transmode. But it kept the complexity within the optical transceivers which could be used with current optical networks. It also enabled new network designs due to the advanced chromatic dispersion and PMD compensations made possible by the coherent technology and the DSP-ASIC.
For 400Gbps, the transition will be simpler. "Going from 100 Gig to 400 Gig will re-use a lot of the technologies used for 100 Gig coherent," says Magnus Olson, director of hardware engineering.
So even if there will be some challenges with higher-speed components, the main challenge will move from the optical transceivers to the network, he says. That is because whatever modulation format is selected for 400Gbps, it will not be possible to fit that signal into current networks keeping both the current channel plan and the reach.
"From an industry point of view, a metro-centric cost reduction of 100Gbps coherent is currently more important than increasing the bit rate to 400Gbps"
"If you choose a 400 Gigabit single carrier modulation format that fits into a 50 Gig channel spacing, the optical performance will be rather poor, resulting in shorter transmission distances," says Persson. Choosing a modulation format that has a reasonable optical performance will require a wider passband. Inevitably there will be a tradeoff between these two parameters, he says.
This will likely lead to different modulation formats being used at 400 Gig, depending on the network application targeted. Several modulation formats are being investigated, says Transmode, but the two most discussed are:
- 4x100Gbps super-channels modulated with DP-QPSK. This is the same as today's modulation format with the same optical performance as 100Gbps, and requires a channel width of 150GHz.
- 2x200Gbps super-channels, modulated with DP-16-QAM. This will have a passband of about 75GHz. It is also possible to put each of the two channels in separate 50GHz-spaced channels and use existing networks The effective bandwidth will then be 100GHz for a 400GHz signal. However, the OSNR performance for this format is about 5-6 dB worse than the 100Gbps super-channels. That equates to about a quarter of the reach at 100Gbps.
As a result, 100Gbps super-channels are more suited to long distance systems while 200Gbps super-channels are applicable to metro/ regional systems.
Since 200Gbps super-channels can use standard 50GHz spacing, they can be used in existing metro networks carrying a mix of traffic including 10Gbps and 40Gbps light paths.
"Both 400 Gig alternatives mentioned have a baud rate of about 32 Gig and therefore do not require a 64 Gbaud photo detector," says Olson. "If you want to go to a single channel 400G with 16-QAM or 32-QAM modulation, you will get 64Gbaud or 51Gbaud rate and then you will need the 64 Gig detector."
The single channel formats, however, have worse OSNR performance than 200Gbps super-channels, about 10-12 dB worse than 100Gbps, says Transmode, and have a similar spectral efficiency as 200Gbps super-channels. "So it is not the most likely candidates for 400 Gig," says Olson. "It is therefore unclear for us if this detector will have a use in 400 Gigabit transmission in the near future."
Transmode points out that the state-of-the-art bit rate has traditionally been limited by the available optics. This has kept the baud rate low by using higher order modulation formats that support more bits per symbol to enable existing, affordable technology to be used.
"But the price you have to pay, as you can not fool physics, is shorter reach due to the OSNR penalty," says Persson.
Now the challenges associated with the DSP-ASIC development will be equally important as the optics to further boost capacity.
The bundling of optical carriers into super-channels is an approach that scales well beyond what can be accomplished with improved optics. "Again, we have to pay the price, in this case eating greater portions of the spectrum," says Persson.
Improving the bandwidth of the balanced detector to the extent done by u2t is a very impressive achievement. But it will not make it alone into new products, modulators and a faster DSP-ASIC will also be required.
"From an industry point of view, a metro-centric cost reduction of 100Gbps coherent is currently more important than increasing the bit rate to 400Gbps," says Olson. "When 100 Gig coherent costs less than 10x10 Gig, both in dollars and watts, the technology will have matured to again allow for scaling the bit rate, using technology that suits the application best."
Ciena:
How the optical performance changes going from 32Gbaud to 64Gbaud depends largely on how well the DSP-ASIC can mitigate the dispersion penalties that get worse with speed as the duration of a symbol narrows.
BPSK goes twice as far as QPSK which goes about 4.5 times as far as 16-QAM
"I would also expect a higher sensitivity would be needed also, so another fundamental impact," says Joe Berthold, vice president of network architecture at Ciena. "We have quite a bit or margin with the WaveLogic 3 [DSP-ASIC] for many popular network link distances, so it may not be a big deal."
With a good implementation of a coherent transmission system, the reach is primarily a function of the modulation format. BPSK goes twice as far as QPSK which goes about 4.5 times as far as 16-QAM, says Berthold.
"On fibres without enough dispersion, a higher baud rate will go 25 percent further than the same modulation format at half of that baud rate, due to the nonlinear propagation effects," says Berthold. This is the opposite of what occurred at 10 Gigabit incoherent. On fibres with plenty of local dispersion, the difference becomes marginal, approximately 0.05 dB, according to Ciena.
Regarding how spectral efficiency changes with symbol rate, doubling the baud rate doubles the spectral occupancy, says Berthold, so the benefit of upping the baud rate is that fewer components are needed for a super-channel.
"Of course if the cost of the higher speed components are higher this benefit could be eroded," he says. "So the 200 Gbps signal using DP-QPSK at 64 Gbaud would nominally require 75GHz of spectrum given spectral shaping that we have available in WaveLogic 3, but only require one laser."
Does Ciena have an view as to when 64Gbaud systems will be deployed in the network?
Berthold says this hard to answer. "It depends on expectations that all elements of the signal path, from modulators and detectors to A/D converters, to DSP circuitry, all work at twice the speed, and you get this speedup for free, or almost."
The question has two parts, he says: When could it be done? And when will it provide a significant cost advantage? "As CMOS geometries narrow, components get faster, but mask sets get much more expensive," says Berthold.
Transmode's evolving packet optical technology mix
- Transmode adds MPLS-TP, Carrier Ethernet 2.0 and OTN
- The three protocols make packet transport more mesh-like and service-aware
- The 'native' in Native Packet Optical 2.0 refers to native Ethernet
Transmode has enhanced its metro and regional network equipment to address the operators' need for more efficient and cost-effective packet transport.
“Native Packet Optical 2.0 extends what the infrastructure can do, with operators having the option to use MPLS-TP, Carrier Ethernet 2.0 and OTN, making the network much more service-aware”
Jon Baldry, Transmode
Three new technologies have been added to create what Transmode calls Native Packet Optical 2.0 (NPO2.0). Multiprotocol Label Switching - Transport Profile (MPLS-TP) was launched in June 2012 to which has now been added the Metro Ethernet Forum's (MEF) latest Carrier Ethernet 2.0 (CE2.0) standard. The company will also have line cards that support Optical Transport Network (OTN) functionality from April 2013.
Until several years ago operators had distinct layer 2 and layer 1 networks. “The first stage of the evolution was to collapse those two layers together,” says Jon Baldry, technical marketing director at Transmode. “NPO2.0 extends what the infrastructure can do, with operators having the option to use MPLS-TP, CE2.0 and OTN, making the network much more service-aware.”
By adopting the enhanced capabilities of NPO2.0, operators can use the same network for multiple services. “A ROADM based optical layer with native packet optical at the wavelength layer,” says Baldry. “That could be a switched video distribution network or a mobile backhaul network; doing many different things but all based on the same stuff.”
Transmode uses native Ethernet in the metro and OTN for efficient traffic aggregation. “We are using native Ethernet frames as the payload in the metro,” says Baldry. “A 10 Gig LAN PHY frame that is moved from node to node, once it is aggregated from Gigabit Ethernet to 10 Gig Ethernet; we are not doing Ethernet over SONET/SDH or Ethernet over OTN.”
Shown are the options as to how layer 2 services can be transported and interfaced to multiple core networks. The Ethernet muxponder supports MPLS-TP, native Ethernet and the option for OTN, all over a ROADM-based optical layer. “It is not just a case of interfacing to three core network types, we can be aware of what is going on in these networks and switch traffic between types,” says Transmode's Jon Baldry. Note: EXMP is the Ethernet muxponder. Source: Transmode.
Once the operator no longer needs to touch the Ethernet traffic, it is then wrapped in an OTN frame for aggregation and transport. This, says Baldry, means that unnecessary wrapping and unwrapping of OTN frames is avoided, with OTN being used only where needed.
There are economical advantages in adopting NPO2.0 for an operator delivering layer 2 services. There are also considerable operational advantages in terms of the way the network can be run using MPLS-TP, the service types offered with CE2.0, and how the metro network interworks with the core network, says Baldry.
MPLS-TP and Carrier Ethernet 2.0
Introducing MPLS-TP and the latest CE2.0 standard benefits transport and services in several ways, says Baldry.
MPLS-TP provides better traffic engineering as well as working practices similar to SONET/SDH that operators are familiar with. “MPLS-TP creates a transport-like way of dealing with Ethernet which is good for operators having to move from a layer-1-only world to a packet world,” says Baldry. MPLS-TP is also claimed to have a lower total cost of ownership compared to IP/MPLS when used in the metro.
The protocol is also more suited to the underlying infrastructure. “Quite a lot of the networks we are deploying have MPLS-TP running on top of a ROADM network, which is naturally mesh-like,” says Baldry.
In contrast Ethernet provides mainly point-to-point and ring-based network protection mechanisms; there is no support for mesh-based restoration. This resiliency option is supported by MPLS-TP with its support of mesh-styled ‘tunnelling’. A MPLS-TP tunnel creates a service layer path over which traffic is sent.
“You can build tunnels and restoration paths through a network in a way that is more suited to the underlying [ROADM-based] infrastructure, thereby adding resiliency when a fibre cut occurs,” says Baldry.
MPLS-TP also benefits service scalability. It is much easier to create a tunnel and its protection scheme and define the services at the end points than to create many individual circuits across the network, each time defining the route and the protection scheme.
“Because MPLS-TP is software-based, we can mix and match MPLS-TP and Ethernet on any port,” says Baldry. “You can use MPLS-TP as much or as little as you like over particular parts of the network.”
The second new technology, the MEF’s Carrier Ethernet 2.0, benefits services. The MEF has extended the range of services available, from three to eight with CE2.0, while improving class-of-service handling and management features.
Transmode says its equipment is CE2.0 compliant and suggests its systems will become CE2.0-certified in the new year.
Hardware
The packet-optical products of Transmode comprise the TM-Series transport platforms and Ethernet demarcation units.
The company's single and double slot cards - Ethernet muxponders – fit into the TM-Series transport platforms. The single-slot Ethernet muxponder has ten, 1 Gigabit Ethernet (GbE) and 2x10GbE interfaces while the double-slot card supports 22, 1GbE and 2x10GbE interfaces. Transmode also offers 10GbE only cards: the single slot is 4x10GbE and the double-slot has 8x10GbE interfaces. These cards are software upgradable to support MPLS-TP and the MEF’s CE2.0.
“In early 2013, we are introducing a couple of new cards – enhanced Ethernet muxponders – with more gutsy processors and optional hardware support for OTN on 10 Gigabit lines,” says Baldry.
The Ethernet demarcation unit, also known as a network interface device (NID), is a relatively small unit that resides for example at a cell site. The unit undertakes such tasks as defining an Ethernet service and performance monitoring. The box or rack mounted units have Gigabit Ethernet uplinks and interface to Transmode’s platforms.
Baldry cites the UK mobile operator, Virgin Media, which is using its platforms for mobile backhaul. Here, the Ethernet demarcation units reside at the cell sites, and at the first aggregation point the10- or 22-port GbE card is used. These Ethernet muxponder cards then feed 10GbE pipes to the 4- or 8-port 10GbE cards.
“For the first few thousand cell sites there are hundreds of these aggregation points,” says Baldry. “And those aggregation points go back to Virgin Media’s 50-odd main sites and it is at those points we put the 8x 10GbE cards.” Thus the traffic is backhauled from the edge of the network and aggregated before being handed over as a 10GbE circuit to Virgin Media’s various radio network controller (RNC) sites.
Transmode says that half of it customers use its existing native packet optical cards in their networks. Since MPLS-TP and CE2.0 are software options, these customers can embrace these features once they are required.
However, operators will only likely start deploying CE2.0-based services once Transmode’s offering becomes certified.
Further reading:
Detailed NPO2.0 application note, click here
Transmode chooses coherent for 100 Gigabit metro
Transmode has detailed its 100 Gigabit metro strategy based on a stackable rack, a concept borrowed from the datacom world.
The Swedish system vendor has adopted coherent detection technology for 100 Gigabit-per-second (Gbps) optical transmission, unlike other recent metro announcements from ADVA Optical Networking and MultiPhy based on 100Gbps direct-detection.
"Metro is a little bit diverse. You see different requirements that you have to adapt to."
Sten Nordell, Transmode
"We are getting requests for this and we think 2012 is when people are going to put in a low number of [100Gbps] links into the metro," says Sten Nordell, CTO at Transmode.
The 100Gbps requirements Transmode is seeing include connecting data centres over various distances. The data centres can be close - tens of kilometers - or hundreds of kilometers apart.
"They [data centre operators] want to get more capacity over longer distances over the fibre they have rented," says Nordell. "That is why we are going down the standards path of coherent technology that gives you that boost in power and distance."
Nordell says that customers typically only want one or two 100Gbps light paths to expand fibre capacity or to connect IP routers over a link already carrying multiple 10Gbps light paths. "Metro is a little bit diverse," he says. "You see different requirements that you have to adapt to."
Rack system approach
Transmode has adopted a stackable approach to its 100Gbps TM-series of chassis. The TM-2000 is a 4U-high dual 100Gbps rack that implements transponder, muxponder or regeneration functions. "We have borrowed from Ethernet switches - you add as you grow," says Nordell.
Up to four TM-2000 are used with one TM-301 or TM-3000 master rack, with the architecture supporting up to 80, 100Gbps wavelengths overall.
"If you have too many ROADMs in the way it is going to hurt you. We have seen that with 40 Gig."
The system also uses daughter boards that support various client-side interfaces while keeping the 100Gbps line-side interface - the most expensive system component - intact. "You can install a muxponder of 10x10Gig modules,” says Nordell. "When an IP router upgrades to a 100 Gig interface, you take out the daughter board and put in a 100 Gig transponder."
Transmode will offer two line-side coherent options, with a reach of 750km or 1,500km. "We want to make sure that customers' metro and long-haul requirements will be covered," says Nordell.
The reach of various 100Gbps technologies for the metro edge, core and regional networks. Source: Gazettabyte
The company chose coherent technology because it is an industry-backed standard. "We can benefit from coherent technology," he says. "If the industry aligns, the volumes of the components come down in price."
Coherent also simplifies the setting up and commissioning of agile photonic networks, especially as more ROADMs are introduced in the metro. "Coherent will help simplify this. All the others are more complex," he says. "Beforehand metro was more point-to-point, now we are seeing more flexibility."
Transmode recently announced it is supplying its systems to Virgin Mobile for mobile backhaul. "That is a metro network with all ROADMs in it," says Nordell. Such networks support multiple paths and that translates to a need for greater reach. "The power budget we need to have in the metro is going up a little bit."
Direct-detection technology was considered by Transmode but it chose coherent as it gives customers a better networking design capability.
Direct detection is also not as spectrally efficient as coherent: 200GHz or 100GHz-wide channels for a 100Gbps signal rather that coherent's 50GHz. "If you have too many ROADMs in the way it is going to hurt you, says Nordell.”We have seen that with 40 Gig."
The TM-2000 rack will begin testing in customers' networks at the start of 2012, with limited availability from mid-2012. The platform and daughter boards will be available in volume by year-end 2012.