I evaluated several campus PON project on both vendor/provider and customer sides over the last 5 years. PON was designed as a last-mile technology for _operators_ to cover huge areas and save on OPEX - that's the usual vendor's mantra. GigE usually takes two fibers to deliver; GigE aggregation requires an Ethernet switch you need to power and maintain - "many points of failure" argument. PON only takes one fiber, splitting a PON signal is done by a cheap passive optical splitter which, once installed, lasts forever. Correct cost comparison between PON and Ethernet is pretty difficult. First, the cost of the actual network _equipment_ (switches, routers etc.) for an Access network (tens of thousands of subscribers) is nothing compared to the civil works - trenching, cabling, permits etc. Second, CPE cost is the most sensitive on that scale. $5 cheaper CPE saves more money than a $50k cheaper OLT. Without scale benefits and (assumed) OpEx reduction, PON projects are usually significantly more expensive. Now, to the projects. I have never heard of seen PON on a DC level. As for the campus, none of the projects took off, and here is why: - PON equipment is proprietary. An OLT (PON hub) from vendor X works only with ONTs from the same vendor. Every other vendor claims there is "some interop" but none was able to do demonstrate. - PON infrastructure - a passive fiber tree - is a) proprietary b) not flexible. You can make any physical topology of your usual p2p fiber segments but a tree is always a tree; plus PON usually requires green APC (angle polished) connectors. - PON US/DS bandwidth allocation is asymmetric. Training, maintenance and support are important, too. Ethernet is ubiquitous, PON engineers are a bit harder to find. Proprietary nature of the product implies that a Huawei PON would look and feel somewhat different than, say, Calix PON hence the knowledge is more vendor-specific. Also, nobody likes vendor lock. If an Access Ethernet switch fails, you can - potentially - replace it with another fairly easily. PON ONT of different vendors may all come from the same OEM like Cambridge but the firmware is different. What did I miss?... Ah, the usual cabling There is a more sophisticated WDM-PON. Ericsson and Teradata had it in development, Infinera offers it as iAccess product - but I haven't tried that yet. Overall, it really depends on a project (getting all the MTBF data and calculating the failure cost was quite a task) but I personally can't see any PON benefits over Ethernet for either campus or DC even in the midterm.
From my personal experience, flexibility with cables plus cheap CWDM filters and colored optics can do magic on the campus level.
Stas On Sat, Jan 21, 2017 at 10:44 AM, Kenneth McRae <kenneth.mcrae@me.com> wrote:
Greeting all,
Is anyone out there using PON in a campus or facility environment? I am talking to a few vendors who are pushing PON as a replacement for edge switching on the campus and in some cases, ToR switch in the DC. Opinions on this technology would be greatly appreciated.
Thanks,
Kenneth