Monomode fiber for 1Gbps to 10Gbps?

[mario_kmc]

Hello all,

I'm making an RFP for fiber optic installation connecting two rooms 15m apart. We will be using single-mode fiber with 1000BASE-LX/LH but I'm also requesting the fiber to support 10Gbps in the future.

I've checked SFP specs and see that both 1000BASE-LX/LH and Cisco SFP-10G-LR can be used with distances longer than 2m without attenuators.

Gigabit ethernet SFP's

10Gbit ethernet SFP+

Question: Do I need to specify any single mode fiber parameter I must pay attention to so I can have without changing the fiber later? (similar to OM1, OM2, OM3 on multimode fiber)?

Thank you

Mario

[Tom Randstrom]

You may want to specify an ITU-T G.652.D compliant singlemode fiber, which has a low water peak and will support CWDM wavelengths.  This white paper from Corning details some of its benefits. 

[mario_kmc]

Hi Tom,

Thanks for your feedback. really helpful info. Had me going for a reading. So much to learn about.

[Alessio Andreoli]

Hi mario,

The answer is yes. From a technical design perspective you must pay attention to all those parameters. The above suggestion about the standards to comply can also be a help to find all what you need for this migration. Nevertheless, I would like to underline the cost for this scalability. It could be an idea to implement now 10GE and then rate-limiting the speed to 1GE by means of policer, policing or shaping.

Alessio

Sent from Cisco Technical Support iPad App

[Tom Randstrom]

If your fiber link is only 15 meters, you could also install OM4 multimode fibers (maybe in addition to singlemode fibers). The SFP-10G-SR transceiver will be much more cost efffective than a singlemode transceiver. 

Cisco SFP-10G-SR

The Cisco 10GBASE-SR Module supports a link length of 26m on standard Fiber Distributed Data Interface (FDDI)-grade multimode fiber (MMF). Using 2000MHz*km MMF (OM3), up to 300m link lengths are possible. Using 4700MHz*km MMF (OM4), up to 400m link lengths are possible.

If you plan on upgrading this 15 meter link to 100G links in the future, then add some additional OM4 multimode fibers (24 fibers for each 10G link), Fiber is fairly inexpensive (future labor isn't).

Good luck!

[viyuan700 · Accepted solution]

If the price diffrence between G652 and G652D is very less you can go for G652D. But if it is substancial then you can go G652 even in future you want to go for 100G. Else as suggested you can go for Multimode Fiber (OM3/4). I feel 100G will be useful for very very large Datacenters. 10G is there from last 10years but even today it doesnot make sense for many. But virtulaization/blades will drive it faster.

You are talking about distances where you don't need feature given by G652D.They are mainly for service provider only at long Haul Distances.

[mario_kmc]

Hi everyone. Thanks for all your feedback.

I had to take some time and do some research about all you have said.

About what has been said:

1. We are currently handling around 400Mbps, 5Gbps will take  some 10-20 years for us (probably) and 100G... not even considering yet.

2. We'll be using 3560X with gigabit ethernet modules changeable to 10Gbps so that part of scalability is taken care of (did not think so much about price really)

3. Because of inexperience single-mode SFP's were ordered. Only after ordering I saw that these distances are usually covered with multi-mode fiber. Thats why we had to go for single mode fiber.

4. Fortunately proposals we have received all have G.652D fiber. I did some reading and only benefit I could get from G.652D fiber is lower attenuation especially at around 1370nm. Does this lower attenuation really matter at such short distances?

[viyuan700]

Lower attenuation is useful when you want to go more distance (with same SFP you can go more distance). so for your case it doesn't matter right now. Who knows in case you need it in future or need more 1/10G though the same pair of fiber then can use CWDM which works around that wavelength. 

Maybe nobody is making G652 anymore. So good you have G652D.

[mario_kmc]

Hi everyone,

Just an extra question. I have seen many references for CWDM. What is the importance of CWDM? What are its applications?

thanks

[viyuan700]

Between 2 location if you have requirement to connect 8 Optical Module in Site A to 8 Optical Module in Site B. You need 8 pair of fibers.

If you are in a building and you have many fiber pair avialble you can use them no need of any extra equipment .

But if your 2 location are far away and you are leasing fiber so instead of leasing 8 pair you can just have 1 pair and use an extra piece of equipment on both sides so all 8 Channels can use 1 pair you have. Compare Cost of 8 fiber pair V/s cost of CWDM equipment. Every optical module will go over a different wavelength/ frequency but in the same fiber. At other end you can again separate them .

[mario_kmc]

Thanks very much for the explanation and patience.

Best regads

MP