I am considering a C9606R for a solution. When it comes the line cards and interfaces I am looking at the C9600-LC-24C line card. When looking at the optics compatibility chart https://optics.cisco.com/?dr=7&dr=5&rh=18&npid=2223 I can see the various SFPs that will support 100G at 10Km, which is what I am interested in. However, there are (2) different types that are available.
- QSFP-100G-LR4-S
- QSFP-100G-LR-S
spec sheet for both devices located here:
When I look at the spec sheets for both items, I can see the following differences:
QSFP-100G-LR4-S:
- uses 4 lanes to transmit data
- does not utilize FEC *
- is significantly more expensive in CCW
QSFP-100G-LR-S
- Uses a single frequency to transmit data
- Utilizes FEC*
- Cheaper
Besides the LR-S using only a single laser, the key difference that I notice is that it supports FEC. I understand that FEC assist in error correction over long distances/fast speeds. I understand that both sides of the link will need to use similar protocols (FEC enabled/not enabled) however, I don't understand if FEC is a capability I should want to employ or not. At first glance my thoughts are to use FEC because of its capability, however, in a recent article I read it mentions the goal to remove FEC from the modules. So I am not sure which route is best any why.
https://blogs.cisco.com/sp/why-single-lambda-100g-is-just-what-networks-need-in-pluggable-optics
