What is the maximum segment length of fiber-optic cable for both single-node and multi-node?

Question

What is the maximum segment length of fiber-optic cable for both single-node and multi-node?

I can't seem to find a straight answer for this. Does anyone know the answer to this or know of somewhere I can reference?

Thanks for taking a look!

Answer 1

It really depends on what kind of distance and bandwidth are part of your requirements.

LR / ER / XR optics are used with single mode. SR optics are used with multimode or OM3 (they're pretty much the same thing).

This is a good resource for how far the laser can be pushed over each fiber with each optic.

http://www.cisco.com/c/en/us/products/collateral/interfaces-modules/transceiver-modules/data_sheet_c78-455693.html

Answer 2

The reason you struggle to find a straight answer is because it depends on multiple factors including

1. The exact type of fiber, "single mode" and "multi mode" are wide categories within which there are many different types of fiber.
2. The data rate you require. For multimode fiber higher data rates mean shorter distances. There is a handy table at https://en.wikipedia.org/wiki/Multi-mode_optical_fiber#Comparison though note that the table doesn't cover 10GBASE-LRM or 10Gbaase-Lx4.
3. What transceivers you use, by spending more on the transceivers and/or using matched pairs from a single manufacturer you can often get more distance on the same fiber.

Assuming you want to run gigabit or 10 gigabit speeds, multimode tends to reach it's limit at a few hundred meters. Exactly what "few" means depends on the precise type of fiber you have and whether you want to run gigabit or 10 gigabit. Getting those distances at 10 gigabit over old fiber will require more expensive LX4 or LRM transcivers.

Singlemode can go much further. As I understand it 100km is about the limit for a single segment without intermediate amplifiaction.