Looking for some opinion on passive optical network deployments instead of traditional copper

[charmstuart97781]

My company is in the early stages of designing a new space (about 100k sq ft) and our architects are pitching a PON instead of copper (most likely CAT 6a). I've never dealt with such a deployment and before I discuss with our IT services provider I want to make sure I understand enough to ask the right questions.

To give some context, my company is in a data intensive industry and we typically have other companies working within our space requiring isolation (done through VLANs) and, at times, significant modification to an area (moving or adding data drops). The reason PON is attractive and why I think it's being pitched is because of the reduced footprint both in space but also on power and cooling. Plus, it would allow to only run copper from the ONT to the outlet rather than all the way back to an IDF.

What should I be aware of before going forward? Right now my understanding is that using VLANs doesn't really change since we do that in the firewall not the switch. All of our IDF switches are unnecessary as we would be using splitters and I need to make sure the ONTs are physically secured. POE would have to be handled through injectors at the rack or at the ONT. There may be a higher upfront cost but will ultimately cost less over time.

Anything beyond that would be greatly appreciated.

[chrihussey]

Hello, 

Just my opinion, but not a fan of PON. Had the same situation a couple of years ago with PON being touted as the greatest thing since sliced bread. My understanding is that it may be effective for provider services like Verizon FiOS, but not so much for LAN environments.

1- The PON splitters effectively mean that up to 32 (possibly more) users (ONTs) are aggregated together. It may have increased since, but the aggregate to the users is 2.4 gig and from the users is 1.2 gig. Meaning 32 users total combined bandwidth is just that. Now if you use ONTs with multiple ports the shared 2.4G/1.2G gets more dense. They'll tell you the algorithms used make it work but in a classic switched environment with CAT6A and each user having a dedicated gig connection, you can see the obvious advantage over PON.

2- There may be a smaller footprint in the IT closet, but the devil is in the details. The ONTs can provide POE, but now wherever you have an ONT you'll need a power receptacle. Also if you have WAPs, wall phones, etc., things can get a little difficult.

3-You can provide power from the TR, but that is also a mess. This requires running the fiber with copper cabling to power the ONT. This means you'll need a power rack in the TR which may require a transformer and probably a UPS.

There are also possible distance limitations with running power with the fiber. Plus the engineers that install and maintain the system will be working with these power wires and connections. The potential for touching hot wires is there.

4- The PON system itself needs to be administered and managed. This will require a central management system with GUI interface as well as maintenance contract. Something else to keep in mind price wise. 

5- It can be more difficult to analyze or diagnose network issues just by the nature of PON. If you want to sniff traffic or connect a device you'll need to do so at a central location and not closer to the issue as PON limits that.

Again my opinion, and I'm sure there are PON advocates out there. But if you are in a "data intensive" environment I would not recommend PON. 

Regards