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Optical/IP

Poll Paints Bright Future for CWDM

Coarse wavelength-division multiplexing (CWDM) could eventually overtake DWDM in metro markets, according to a Light Reading Research Poll on the subject staged in October.

A total of 249 people took the poll, and -- surprisingly -- 43 percent of them went so far as to say that CWDM would overtake DWDM in metro markets. Another 35 percent said CWDM would be widely deployed, but not as widely deployed as DWDM.

The full results of the poll can be seen here.

Until recently, CWDM was considered something of a poor cousin to DWDM -- partly because it could pump only up to eight channels down a pair of fibers, and partly because it wouldn't work over distances of more than about 50 kilometers.

Now sentiment appears to have changed, mainly because CWDM promises to help carriers out of a jam by boosting bandwidths in metro networks without busting the bank.

Opinions vary over how much carriers can actually save with the technology. Some CWDM equipment vendors say they can cut costs by a factor of three, while DWDM vendors say savings rarely exceed 20 percent. In the Light Reading poll, 30 percent of respondents thought CWDM could deliver savings of more than 50 percent compared to DWDM. Only 25 percent of respondents thought savings would be 20 percent or less.

Confidence in CWDM as a technology appears to have grown since a 16-channel version was standardized by the International Telecommunication Union, Standardization Sector (ITU-T) last June. In the Light Reading poll, 82 percent of respondents said CWDM was mature enough to be used in metro networks; only 11 percent thought it wasn't.

The other reason for CWDM's increasing popularity is probably the growing availability of low water peak fiber, required for 16-channel systems, and the arrival of innovative CWDM solutions from the likes of Cisco Systems Inc. (Nasdaq: CSCO) and Transmode Systems AB (see Cisco Adds CWDM to Switches and Transmode Makes a Little Go a Long Way).

These and other issues concerning CWDM will be put in the spotlight in a Light Reading Webinar scheduled for next Tuesday, November 19, and hosted by Yours Truly. To get more information and to register for the Webinar, entitled "CWDM: Optical Capacity Without the Cost", please click here.

— Peter Heywood, Founding Editor, Light Reading
www.lightreading.com
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Vesting 12/4/2012 | 9:20:56 PM
re: Poll Paints Bright Future for CWDM The results of this poll are very interesting. Could it be that some CWDM player has managed to tip the scales in these responses or could it be that a carrier managed to influence the response in an attempt to force the price of DWDM down. I find it interesting that this article does not mention who was polled.

CWDM will continue to have impacts on the enterprise markets but most major carriers (RBOC's etc.) will never be satisfied with an 8 to 16 lambda maximum configuration with limited distance specifications. Not to mention the fact that due to the potential volume of business from these carriers most of them can demand price points for DWDM that can come close to those supported by CWDM equipment providers.

CWDM has its niche market, but DWDM will continue to maintain the lions share.
photonphoto 12/4/2012 | 9:20:56 PM
re: Poll Paints Bright Future for CWDM Comparing attributes between CWDM and DWDM is only part of the question... what about CWDM vs. 10G serial solutions? In the end, won't 10G transceivers provide the metro bandwidth without the cost associated with WDM solutions? Just like we see at 2.5G today.
Touch 12/4/2012 | 9:20:54 PM
re: Poll Paints Bright Future for CWDM I have to agree with gea. Small form, pluggable (SFP)CWDM modules will soon hit $100. In two years they will be around $50 per port (look at the quarterly price erosion of GBICs). Un-cooled FPs remove the need for temperature compensation and wavelength management and wide channel spacings mean ultra-low cost optical mux/demux.

DWDM will remain in the long-haul. Cost rules in metro and CWDM will win.

Looking further out, 10 Gb/s XFP looks quite promising.

Just an opinion. Wonder what BobbyMax thinks?

Touch
gea 12/4/2012 | 9:20:54 PM
re: Poll Paints Bright Future for CWDM Vesting:

2 years ago I would have said the same thing. Now (being a long-time DWDM engineer) I totally disagree, and the reason is simple:

Pluggable transceiver optics.

There are already a whole batch of companies that make CWDM transceivers that are completely compatible with extant pluggable transceiver MSAs (eg: Small Form factor pluggable).

This may mean that CWDM ends up becomming a low-cost extension of GbE and ethernet technologies. Indeed, imagine a scenario where your LAN guy is buying passive optics and transcceivers from Radio Shack in order to upgrade bandwidth between two intra-city switch/routers. He'll simply buy the needed wavelengths and plug them into the switch (even a switch that has existed since well before CWDM was considered). This means NO TRANSPONDERS.

As for distance limiations, off-the-shelf transceivers already support point-to-point distances of 80 km and high. Add the losses due to the passive optics and you still have more distance than 95% of Metro deployments will ever need.

ANother significant factor is this 16 wavelength standard. Looks to me that the 8 and now 16 wavelength versions of CWDM will indeed be a "standard", and the fact that there's no optical amplifications means there will be plenty of transverse compatibility. Thus, we won't have a repeat of DWDM's lack-of-a-defacto-standard.

No, CWDM is going to CRUSH DWDM in the MEtro, and I am someone who was a "true believer" in DWDM.
Eru 12/4/2012 | 9:20:53 PM
re: Poll Paints Bright Future for CWDM I am interested to understand more about CWDM.

1. What about the scalability issue? How do you scale beyond 16 chs? New fiber or DWDM band?

2. What about logistics? I thought the logistics issue to be severe also for CWDM. E.g. in laser chip production, can you use the same base wafer for all laser wavelengths? Tunability by temperature?

3. Are there components for optical add/drop? Reconfigurable?

Regards, Eru
belas_knap 12/4/2012 | 9:20:48 PM
re: Poll Paints Bright Future for CWDM I don't think this poll has been hijacked by any CWDM manufacturer, but it does reflect basic market dynamics from what I am seeing in today's market demand (and no, I don't work for a CWDM startup). From my recent experience (and these are very generalistic points about the market and I know there are many exceptions that can be argued) the CWDM solutions are finding favour with larger Enterprise networks intent on low-cost, GigE/multiservice campus applications (DWDM still rules for point-to-point Storage) particularly when they can plug in low-cost optical GBICs to their LAN/Ethernet switches and use passive opticsmuxes to implement the rings/OADMs - it's a nice solution for Video or VOIP, for example, and brings a better cost/technology advantage to implementing these on a (wide-area) Campus.
For Service Providers, they are interested in CWDM for the same reason - low-cost access to the LAN Enterprise structure, particularly if they can get to it by plugging in a sub-$1000 transceiver rather than deploying a full-blown WDM shelf on the customer premises- but this becomes a little more dubious if they are looking for managed Storage Networking solutions or Fibre-gain in the core, since DWDM (partcularly in the traditional SPs) is still the "preferred traditional" technology, although pricing pressure as well as the adoption of Metro Ethernet solutions will probably force them to look at either CWDM technologies or integrated WDM "multiservice" switches as time moves forward. Another factor for DWDM is that the SPs who generally inplemented this in the MetroCore were doing so for fibre-gain (i.e. they were leasing the fibre & the cost of DWDM justified the cost versus leasing additional fibre) but many of the smaller SPs/CLECs have now disappeared, and the technology is now more geared towards higher revenue-generating service delivery and access to the Enterprise/campus infrastructures.
The adoption of CWDM by the Storage suppliers (EMC, IBM, HP, etc) will be a major factor also - generally Enterprises & SPs will only deploy WDM for storage solutions based on certification by these key vendors, and if they don't certify, then the adoption rate will be slow. This hasn't happened yet as far as I know for any CWDM solution, but I suspect it may do soon. But this in itself becomes interesting, and as storage moves forward with the doption of FCIP/iSCSI type solutions, CWDM again helps the economics of deploying these newer technologies into customers looking to adopt lower-cost technologies.
optigirl 12/4/2012 | 9:20:44 PM
re: Poll Paints Bright Future for CWDM Good Post!!! That merits a "5" in my book. I also caught this one on my email this morning....

http://www.cir-inc.com/resourc...
mordecai 12/4/2012 | 9:20:41 PM
re: Poll Paints Bright Future for CWDM You are all way off base. equipment cost is not the issue. it is network cost, and management cost, for carriers and service providers of any scale.

unless you are all debating a one-off enterprise network, in which case anything you can sell them goes.

quit thinking about point to points and single oadm rings for carriers. you are helping no one on that train of thought.

and another thing. tell me you can make a 2.5G DFB for 100$ in an SFP. that would be something. don't talk about gbe optics.
wayland_smithy 12/4/2012 | 9:20:35 PM
re: Poll Paints Bright Future for CWDM Fair point on the number of channels being deployed: average first deployment that I've seen tends to be 3-7 channels in SP sector, with a max. of around 12-14 in the Metro (average 7-10 is about right). Again, however, the exception will be for Storage Area Networking applications where 20+ channels is not uncommon. Since > 50-60% of WDM is heading into non-SPs anyway (either directrly or as managed/deployed service by SPs), it would be interesting to ask these end customers their view on it (mainly financial private sector) and especially if they would be willing to adopt CWDM technology over DWDM ?

---------------------------------------------

On costs, the webinar includes an analysis of the capex savings when using CWDM rather than DWDM in a typical metro application.

On scalability, we make a couple of points:

1. Right now, most metro WDM systems have got less than 8 channels lit. So CWDM would do the job. This comes from the survey we did last month. We had 221 responses and 75% of them were service providers, and 2/3 of the folk that had deployed WDM had deployed 9 or less channels.

2. Scalability is a bit of a red herring anyhow. It's possible to combine CWDM with DWDM - so you can start off reaping the low cost benefits of CWDM and then swap a couple of CWDM channels for a whole bunch of DWDM channels. Cisco is already doing this, apparently.

Tune in to the webinar and find out more!

Peter
Peter Heywood 12/4/2012 | 9:20:35 PM
re: Poll Paints Bright Future for CWDM A lot of these issues will be addressed in the webinar we're running on Tuesday:

http://www.lightreading.com/we...

On costs, the webinar includes an analysis of the capex savings when using CWDM rather than DWDM in a typical metro application.

On scalability, we make a couple of points:

1. Right now, most metro WDM systems have got less than 8 channels lit. So CWDM would do the job. This comes from the survey we did last month. We had 221 responses and 75% of them were service providers, and 2/3 of the folk that had deployed WDM had deployed 9 or less channels.

2. Scalability is a bit of a red herring anyhow. It's possible to combine CWDM with DWDM - so you can start off reaping the low cost benefits of CWDM and then swap a couple of CWDM channels for a whole bunch of DWDM channels. Cisco is already doing this, apparently.

Tune in to the webinar and find out more!

Peter
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