SONET versus DWDM

A little confusion surrounding metro technologies. When should you deploy next-generation SONET versus DWDM versus Ethernet, etc.?
TIA
Pam

The use of one doesn't necessarily rule out the concurrent use of the other (or any of the others).
DWDM is neutral as to the type of signalling that it can carry; it's just a way of increasing the apparent bandwidth over a given pair of SM fiber. In a high-density metro area, it's likely to be far cheaper to deploy WDM / DWDM than to pull additional media. For an existing plant, the bandwidth multiplication frequently translates to more efficiency and lower per-unit transmission costs for a given span.
In a large campus environment, using DWDM to "multiply the bandwidth" is usually a faster solution to implement than trenching-in new media or pulling more fiber into the existing raceways.
WDM / DWDM is just a way to "fatten up" the fiber.
FWIW
Scott

Similar Messages

Sonet/SDH DWDM and ethernet

Hi
Rather a broad title i know. I am primarily an IP person and now need to get up to speed on some of the optical technologies.
I have done some reading around SONET, DWDM, Metro ethernet etc. but i am still struggling to understand a few basics i think.
I appreciate that Sonet/SDH can run over DWDM but i believe you can also run ethernet natively over DWDM.
If you were building a new optical network from scratch would you consider utilising SONET/SDH and if so what would be the reasoning behind it.
I guess where my confusion comes from is there is Ethernet over Sonet, Packet over Sonet etc. but are these technologies there simply because there is such a large installed base of Sonet/SDH or is there another reason eg. Sonet/SDH provide far more reliability for packet transfer with the ability to guarantee delays etc.
Any insights would be much appreciated
Jon

1. Yes, take a deep dive into the ONS15454 documentation. We have been running gig/e over dwdm for about 5 years.
2. Yes, but for very specific uses. For example a metro based environment is well suited to sonet/dwdm topologies, Data center to data center links that require high capacity and recoverability (see the stuff on APS in sonet).
3. IMHO SONET provides the basis for branching into Ethernet over sonet etc...given the frame size, error correction, in band management its a great technology for High availability/Bandwidth. the ability to run ethernet keeps you from having to buy very expensive POS line cards.

I want to be a optical specialist SDH

i cant get thing how to start reading and geathering material???

For anyone with access to Cisco Learning Connection (any CCNA or above I believe), you can access a number of online courses for free following the links off of the Optical Specialist page. This will provide you some good insight into the basics of SONET/SDH and fiber optic communication.
http://www.cisco.com/web/learning/le3/le2/le41/le82/le51/learning_certification_type_home_extra_level.html
I recommend Cisco Press's Optical Network Design and Implementation book. It covers the basics of fiber optics as well as SONET/SDH, DWDM and provisioning on the 15454 as well.
http://www.ciscopress.com/title/1587051052
Also, http://www.cisco.com/en/US/products/hw/optical/ps2006/tsd_products_support_series_home.html includes lots of useful information on network setup, timing, design, etc, as well as links to all documentation for all software revisions.
Hope this helps give you some direction,
Josh

Self study sdh certification

Hi guys,
I plan to prepare for 642-321 certification (optical SDH). Knowing that I'm beginner in optical network (I got some basics) but I've a good network background (CCNA), do you that's reasonable to prepare by myself ?If yes, which book do you recommand ? Is it a mandatory to do labs with ONS routers ?
Thank you.

For anyone with access to Cisco Learning Connection (any CCNA or above I believe), you can access a number of online courses for free following the links off of the Optical Specialist page. This will provide you some good insight into the basics of SONET/SDH and fiber optic communication.
http://www.cisco.com/web/learning/le3/le2/le41/le82/le51/learning_certification_type_home_extra_level.html
I recommend Cisco Press's Optical Network Design and Implementation book. It covers the basics of fiber optics as well as SONET/SDH, DWDM and provisioning on the 15454 as well.
http://www.ciscopress.com/title/1587051052
Also, http://www.cisco.com/en/US/products/hw/optical/ps2006/tsd_products_support_series_home.html includes lots of useful information on network setup, timing, design, etc, as well as links to all documentation for all software revisions.
Honestly, I would not recommend self-study as a sole preparation method. I worked on a 15454 SONET network for 3 years before attending a training bootcamp at Global Knowledge. SONET is not like regular networking at all so your CCNA experience will really only help as far as connecting the ONS to an IP network for management.
Hope this helps give you some direction,
Josh

Mixing SONET/DWDM Cards in a ONS 15454

All,
To my understanding, there are some limitations to mixing SONET line cards with DWDM line cards in the same ONS 15454 chassis. I believe one of the limitations had to do with the line card placement versus a OSC-M and OSC. I can't remember the draw backs of doing the above, but there was some negative.
Are there any more draw backs, limitaitons or gotchas?
Also, generally, the optical engineers I spoke to recommended never mixing the cards and keeping them in seperate chassis.

Hello Jason,
Mixing SONET/SDH and DWDM functions in the same chassis is a supported configuration on the ONS 15454 platform.
As was stated in the other posts, you would have to install the SONET/SDH crossconnect cards in the chassis in order to have the HO/LO functionality.
You are right, that there is an impact on the card placement in the chassis, however you can force the planning tool (Cisco TransportPlanner) to leave the required slots for the XC cards empty when designing the DWDM network.
The model described so far is what is commonly referred to as a "hybrid" node.
There is one other element in the toolchest however - The ADM-on-a-Blade (see http://www.cisco.com/en/US/partner/prod/collateral/optical/ps5724/ps2006/ps5320/product_data_sheet0900aecd805f0e80.html). This network element is an integrated part of the DWDM personality of the ONS 15454 and provides SONET/SDH switching and client ports on the blade. Please note however, that this network element provides only a high-order crossconnect.
It is generally true that one would usually keep SONET/SDH network elements in separate chassis. However, from a network management perspective these separate chassis can form a single node.
Hope that helps
/Dirk

Basic:Metro Ethernet and DWDM vs SONET question

Hey, my understanding is that in order to deliver Metro Ethernet solutions, one system must be based on DWDM.
SONET, for example, cannot deliver Metro Ethernetsince that is based on TDM (not Ethernet, duhhh).
If the above is right, so I want to confirm that there is no other technology out there besides DWDM which can deliver Metro Ethernet services for enterprise customers?

Any number of underlying technologies can be used to deliver Metro Ethernet services - DWDM, SONET, pure play Ethernet over metro area fiber, etc.
It's more of an economic (what installed base does the carrier have or able to obtain the use of and at what cost) and efficiency (how much of the overall capacity can be feasibly broken into resellable Ethernet services without too much stranded or wasted capacity) question than a technological one. Some technologies lend themselves better to one or the other of those factors thus their dominance in certain markets.
The industry is very adept at achieving previously unthought-of solutions through the introduction of additional layers of abstraction (e., Ethernet over SONET, inverse multiplexing, etc.)

IP over OTN or IP over DWDM?

these are two main trend in IP core Network construction.
The core different between them is how to dealing with the TDM service or other small granularity service in electrical layer. in Router or in OTN?
What is your opinion? I find many expert or communication fancier here, so beg your answers.

The core different between them is how to dealing with the TDM service or other small granularity service in electrical layer. in Router or in OTN?
As per my knowledge, difference between IP over DWDM or IP over OTN is which method can take all type of traffic (voice, data, video etc ) in efficient way not just TDM service or granularity (ROuter cannot beat SONET/SDH boxes in handling TDM traffic).
Most of the traffic now a days is IP not TDM, whereas OTN are good for TDM
Question is what can take packet effieciently without too many layers in between. Whether to add IP feature to OTN or Transport feature to Router.
I have no answer who will win IP in router or OTN but IP over DWDM (In router ) will not be the best solution. This method is good for point to point High speed connection things will change if you have lot of traffic to crossconnect.
In other post you have question that how can you separate traffic on different wavelngths, what do you think will your router will act as a crossconnect to segregate different traffic or what if you need only 5 Gig to point A and 5 Gig to point B will the router grrom that traffic?

OC-12 POS blades in GSR routers and DWDM Add Drop Mux's

I have several GSR routers with OC-12 POS blades using OSPF connected to a DWDM ring using Nortel's Optera 5200. It appears that whenever a line side protection switch takes place, that the POS blades react to this, and reconverge OSPF even though the protection switch is <50ms. Do the Cisco POS blades look at standard GR253 Sonet parameters to detect a switch and drop the Interface? Is there a listing of default parameters for the POS blades? I've seen reference all over the CCO to a Standards compliance document, but it can't be found when I follow the link. In theory, the POS blade should never detect a protection switch <50ms and should stay up.

If there is a protection switching on the path (in the DWDM network), AIS-P is sent to the POS line terminating equipment. By default,the POS interface detects path AIS, path RDI or B3 threshold crossing alarms, and brings down the interface until the alarm has been cleared for 10 seconds. This is because otherwise it would take three missed keepalives (3*10=30s) to detect an unprotected path failure.
One solution is to increase the OSPF Shortest Path First calculation interval. The default is 5 seconds. This time can be changed with the "spf-interval " IOS command.
Beginning from IOS 12.0(15.5)S there is another solution: you can cofigure a holdoff time before line alarms trigger the POS link down, using the "pos delay triggers path " command. The parameter is between 0 and 511, where 0 means disabling this feature. If you omit the parameter, it assumes a default of 100 ms, which enables protection switching on the path and the POS interface still remains up.

Dwdm cisco product selection

Hello all,
i wanted to connect DC to DR site by 10g link.if i get the dark fibre, which Cisco optical product will meet my requirements for dwdm connection. i checked ONS 15454 but it seems its bit big as i am just using 1 pair of fiber.
Any suggetions.
thanks in advance.

We are not saying that the 15454 is the box for you. The distance and your expected wavelength growth helps determine what system to pick.
You mentioned your wanting to transport 1G links as well, then maybe a passive CWDM solution would work (see link below). This solution will also allow for a 1310nm channel to be added that could possibly be used with your 10G X2 module. There are also options to integrate with DWDM to add additional wavelengths (2nd link below).
CWDM Solution
<http://www.cisco.com/en/US/products/ps6575/index.html>
EDWDM Solution
<https://www.cisco.com/en/US/prod/collateral/modules/ps5455/product_data_sheet0900aecd806a1c36.html>
These passive systems can be easy to use versus deploying a full-blown DWDM system.
Hope this helps!

The difference between ONS-SC-2G and DWDM-SFP

Our datacenter needs to summary 6 wavelength from the sub-datacenters. All sub-DCs need to communicate with our DC. We have 6509E,15216 MUX/DEMUX and 15454-SA-HD=.
Wavelength list:
DWDM SFP 1535.04 nm SFP (100 GHz ITU grid)
DWDM SFP 1534.25 nm SFP (100 GHz ITU grid)
DWDM SFP 1532.68 nm SFP (100 GHz ITU grid)
DWDM SFP 1531.90 nm SFP (100 GHz ITU grid)
DWDM SFP 1531.12 nm SFP (100 GHz ITU grid)
DWDM SFP 1530.33 nm SFP (100 GHz ITU grid)
Which SFP module do we need to use in our datacenter?
For example DWDM-SFP-3033= and ONS-SC-2G-30.3=. Which should we choose?
Which board should they be inserted and working on?

Hi,
- Do you have any design CTP file?
- Are you already have channels betwen DCs?
This modules have same specification, but different hard-coded part number inside.
Spec for DWDM-SFP-XXXX=:
http://www.cisco.com/c/en/us/products/collateral/interfaces-modules/dwdm-transceiver-modules/product_data_sheet0900aecd80582763.html
Table 2. Optical Parameters
Spec for ONS-SC-2G-XX.X=:
Table 29. CWDM SFP Modules: Optical Specifications
Table 30. DWDM SFP Modules: Optical Specifications
Table 31. DWDM SFP Modules: Optical Performance
Now you can see that they are the same specification.
- If you will use DWDM-SFP-XXXX= in ONS chassis it will work BUT in CTC you will see alarm "Provisioning mismatch".
- If you will use ONS-SC-2G-XX.X= in ONS it will work fine.
- If use ONS-SC-2G-XX.X= in 6k it will work, but you should use DWDM-SFP-XXXX= in 6k Catalyst and connect it directly to 15216 MUX\DMX if distance short. Need CTP design file to check it.

Outputting DVI to HDMI input in LCD TV versus using the DVI to RGB ?

I am thinking of buying a mac mini to connect to a Toshiba 20HL85 TV in the lounge primarily to act as a "media server" and accessing Front Row for music, photo's, DVD watching etc. The question is which connection to use to go from the mini to the TV for Video (audio is fine as it will route into my AV Receiver)? The TV has an HDMI input, component video, s-video and a VGA port. The user manual for the TV says:
Note: The HDMI jack is not intended for connection to and should not be used with a personal computer. For PC connection, use VGA cable and connect to the VGA port. The VGA port allows the following resolutions:
Monitor Display modes:
VGA 640x480 60Hz
SVGA 800x600 56.3Hz
SVGA 800x600 60.3Hz
XGA 1024x768 60Hz
WXGA 1280x720 60Hz
WXGA 1280x768 60Hz
I wanted to know a few things as I have no experience with the MAC mini and HDMI:
1. Will I not get a better/crisper/sharper picture if I connect through a digital port like HDMI versus going through the VGA port?
2. I have checked a few LCD TV's user manuals and they all seem to say the same thing i.e. "Do not connect a PC to the HDMI port" - I fail to understand this when the Apple site specifically says under "accessories for the MAC mini" that "HDMI is electrically similar to DVI, but has a different physical connector that may include an audio signal. You’ll need a DVI to HDMI adapter, such as the Belkin PureAV HDMI to DVI cable to use these televisions".
3. What am I missing? Should I just go ahead and buy the DVI to HDMI cable and MAC mini and plug it in i.e. has anyone done this and had it work? Is it better than VGA (I would hope so)?
Bottom line is does the MAC mini connect to any TV with an HDMI port or are there different types of HDMI ports and hence I need to search for the right TV first? If so, what must I look for? Thanks for any help I can get.
Power Mac G5 Dual 2GHz Mac OS X (10.4.5)

One word of advice. I just hooked up my mini to my 32" Lowe HD TV using a DVI to HDMI cable and it doesn't just work. The native resolution of the TV is not available for whatever reason so I have to bodge another resolution which looks terrible. When I plug my powerbook in via a DVI to VGA connector it just does work selecting the correct resolution automatically.
Either the problem lies with the mini or with connecting to the HDMI socket. As the HDMI is simply a dvi with audio I can't see why it would cause problems but who knows. Given all the other problems I am currently having with the mini I am pointing the finger in that direction currently.

Billing doc cost PCA versus GL

The billing doc cost should be different for the PCA posting versus the GL posting. We have transfer pricing activated as well as material ledger. On the material master the standard price for legal valuation is different than profit center valuation and that is fine. When the billing doc posts it uses standard price for legal valuation for the GL posting. It should use standard price for profit center valuation. It uses legal valuation instead. Goods issue does use the correct standard price for GL versus PCA though.
How do I make the billing doc use the correct standard price ( profit center valuation ) for PCA?

Hi,
I am a bit confuesed on scenario explained by you and I am tring to restate the same:
1. You are using Transfer Pricing and Material Ledger is active.
2. You have different prices updated in Standard Price for Legal and Profit Center Valuations respectively.
3. When you make a goods issue, the system uses the Standard Price in the Legal Valuatoin for accounting.
4. You need the system to use Profit Center Valuation Price for accounting.
Opinion.
The Goods issue as updated in the Financial Accounting should use only the Legal Valuation values. The Profit Center Document anyhow will have the cost of sales based on the profit center valuation. This is by design and correct approach.
If your question is related to values posted in Profitability Analysis. You need to activate profit center valuation in PA and then you will see that both values flow to Profitability Analysis.
Hope this helps you.
Varadharajan

Performance: Reports Builder versus Running on mid tier report server.

Folks are wondering why a report takes 15 minutes when running on the middle tier report server, paper layout, pdf output displayed via adobe, versus running the paper layout from a laptop within Reports Builder.
Any thoughts about the performance differences we now face with the 3 tier set up or suggestions on what we might tweak?

hello,
unfortunately your post did not specify what the difference in performance is and whether you are connecting to the same database and what platform your deployment environment as oppsed to your dev environment is.
there are certainly some performance differences expected if the depoloyment platform is significantly different from the development paltform, but those differences should not be significant.
there are certain things that might cause performance differences (e.g. graphs in reports, using DISPLAY vs. DEFAULT_DISPLAY on unix platforms, etc.) so knowing a bit more about your platform would be helpful.
also it would be interesting to know if you see a similar degredation with other reports or even the test.rdf that comes with the product. last, but not least, have you tried to deploy your report to the OC4J that comes with the developer suite ? if so, do you see timings similar to the builder or more to your app server execution times ?
thanks,
philipp

Authorized versus Associated.....trying to share content

What is the difference between a computer being AUTHORIZED to play content from an iTunes account versus a computer being ASSOCIATED with a device so it can be synced and play the content? It seems multiple computers can be AUTHORIZED to play content from multiple iTunes account but each device can only be ASSOCIATED with one iTunes account (or is it one computer) at a time. Is that correct?
If so, can all the AUTHORIZED content on a computer (even if from multiple iTunes accounts) be synced to one ASSOCIATED iPad?
I have a Work Computer (PC), Associated Work iPad and Work iTunes Account and a separate Home Computer (iMac), Associated Home iPad and Home iTunes account. I am trying to figure out how to share content? Currently all my content is in my Home iTunes Account / Computer. My Work iPad, Work iTunes Account are both new and I want to share some of my Home iTunes content on my Work iPad.
I am concerned when I read that once a device is ASSOCIATED with an iTunes account it can not be ASSOCIATED with a different account for 90 days. I can't risk ASSOCIATING my Work iPad with my Personal iTunes Account and being locked out from syncing my Work iTunes account on my Work iPad for 90 days.

Okay, I figured it out myself and will document it here so others may benefit.
A computer can be AUTHORIZED to play/use content purchsed from multiple iTunes Accounts. There is a limit to the number of computers that can be AUTHORIZED per account (5 total) but no limit as to how many accounts a computer can be AUTHORIZED to play. Once you have AUTHORIZED all the accounts AND downloaded all the purchased content from each account to a computer, this content can be also be played on any device ASSOCIATED with the computer. A device can only be ASSOCIATED to one computer but one computer can have many devices ASSOCIATED to it. As an example, you can use apps purchased on from multiple iTunes accounts on an iPad as long as the computer the iPad is ASSOCIATED with is AUTHORIZED to use/play the content for each of the accounts. Another example: if you also purchased music from all the iTunes accounts, you could listen to it on an iPad, iPhone and iPod as long as all three were ASSOCIATED with the computer where all the accounts were AUTHORIZED.
Hope this helps.

Multiple versus a single collection search with Verity

I have a simple question about Verity search collection.
We have been using verity for a number of years, but we have
never done
any real performance testing in regards to a single
collection versus many.
All documentation and articles argue for multiple small
collections when
indexing for better indexing performance. But what is the
performance
hit when searching 2 collections instead of 1 combined
collection?
How about 4 collections instead of 1?
Thanks
Don Vaillancourt
Director of Software Development
WEB IMPACT INC.
phone: 416-815-2000 ext. 245
fax: 416-815-2001
toll free: 866-319-1573 ext. 245
email: [email protected] <mailto:[email protected]>
blackberry: [email protected]
<mailto:[email protected]>
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http://www.web-impact.com
address:
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We are searching 7 collections with some 100.000 documents. I
have not noticed any performance issues compared to searching only
one collection.

SONET versus DWDM

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