Hello fellow NANOG members 
Let me start with a little bit of background, my day job is a Network Engineer for a local university where we have primarily a Cisco environment from phones to switching to routing, etc. Before my time, we hired a contractor to design a GPON LAN system for a new building as a cost saving measure (though I am not sure how successful that was).
Either way, the contractor is about to hand the system off to us, and we have gone through the training and such, and I feel confident in my ability to manage the system, but we have a few questions that the manufacturer of our equipment and our contractor didn’t really want to answer. We are currently using a Dasan Zhone MXK-F1419 with several different downstream ONT models (all Zhone).
-We would like to consider use of 3rd party GPON B+ Optics on the linecards to add redundancy to the splitter (as the cost of 1st party are too high). Does anyone have experience with 3rd party vendors/compatibility/stability issues? We were told they theoretically should work and just throw a log event, but it hasn’t been tested. If so, what vendors would you recommend? So far all we’ve really seen are Ubiquiti and Fiberstore optics.
-As GPON is a standard itself, I’m aware interoperability between OLT and ONT vendors is heavily limited… Does anyone have any experience using say, Zhone ONT’s with a different model OLT, or Zhone ONT’s with a different model OLT? I’ve heard word that Zhone ONT’s may be able to work with Nokia OLT’s but it’s technically not supported.
-We’ve already experienced some pretty big stability issues (have replaced 1 line card 5 times…), our contractor is saying it’s just because we were a pretty early adopter of this line and that they’ve fixed it and fixed internal policies to add additional QA and testing before shipping to customers. Does anyone have any experience with working with Zhone and their overall stability of components?
- Any other thoughts/gotchas/advice for deploying a GPON environment in a corporate LAN? (or about deploying a Zhone solution) It’s pretty service provider oriented, and is incredible noticeable in the CLI.
Feel free to contact me offlist if you have any pertinent info that you don’t want on the list.
Thanks,
Nick Bogle
nick@bogle.se
How to deploy with Zhone is to put it in the garbage. I have more than enough horror stories from the provider side of things and enough of their TAC literally screaming at me because I called out of regular hours how my problems are physical fiber issues when it never is. They’ve also caused an 18 hour outage “Just trying to do some quick database cleanup” which worked, if you count wiping it as cleaning. Their GUI for ZMS is awful and their TAC doesn’t even know how to use it. It’s effectively a dead product. Their #1 issue has always been their support but nothing ever seems to improve and I saw a lot of support managers keep rotating in and out while their actual engineers ever changed back when I paid attention.
Rip it out and run 9/125 SMF fiber home runs. Use BiDi SFPs to re-use your existing (likely SMF thankfully) cable plant. My opinion.
-Ben. AS15206
This,
Rip it out
Sorry this isn’t what you want to hear. 3rd party optics may work but when they don’t Zhone support will not help you.
I recommend Zhone to my competitors.
The first question to ask yourself is: Why does this need to be GPON?
The primary advantage of GPON is that it’s passive (on the distribution side, at least) - this makes it ideal for building networks where most of your infrastructure located in places that getting power is infeasible: for instance, common residential fibre networks where most of your infrastructure lives on unpowered poles or in ducts/chambers.
I have not yet come across a network closet which doesn’t have provisions for power: If this is a small-to-medium sized campus network you’d be better served by running ordinary optical ethernet and dropping switches where you need to aggregate capacity.
GPON is a rabbit hole that you do not want to go down, if you can feasibly avoid it: Ordinary ethernet is simply easier.
~a
-We would like to consider use of 3rd party GPON B+ Optics on the linecards to add redundancy to the splitter (as the cost of 1st party are too high). Does anyone have experience with 3rd party vendors/compatibility/stability issues? We were told they theoretically should work and just throw a log event, but it hasn't been tested. If so, what vendors would you recommend? So far all we've really seen are Ubiquiti and Fiberstore optics.
I mean, it'll probably work, but considering the extra requirements placed on PON optics and the relatively low cost of them compared to the rest of the system, I'd be inclined to stick with either ones sold by your vendor or at least buying something they re-label from an authorized distributor of the OEM.
-As GPON is a standard itself, I'm aware interoperability between OLT and ONT vendors is heavily limited.. Does anyone have any experience using say, Zhone ONT's with a different model OLT, or Zhone ONT's with a different model OLT? I've heard word that Zhone ONT's may be able to work with Nokia OLT's but it's technically not supported.
Yeah, good luck with that. There's some limited degree of interoperability, but you'll often lose management features, at minimum. Some GPON OLT vendors do have a limited list of "qualified" 3rd party ONTs that they maintain for when their 1st-party ones don't fit the bill. Stick to 1st-party when you can and drop to "qualified" 3rd party ones if you absolutely have to. Anything else is going to be a support and maintenance nightmare.
-We've already experienced some pretty big stability issues (have replaced 1 line card 5 times..), our contractor is saying it's just because we were a pretty early adopter of this line and that they've fixed it and fixed internal policies to add additional QA and testing before shipping to customers. Does anyone have any experience with working with Zhone and their overall stability of components?
Um, GPON is well established in the field. If you've got stability issues, letting your vendor blame it on being an "early adopter" is total BS. Now if you were deploying NG-PON2 or something, I'd maybe, MAYBE let it slide as long as they gave me a good support contact.
- Any other thoughts/gotchas/advice for deploying a GPON environment in a corporate LAN? (or about deploying a Zhone solution) It's pretty service provider oriented, and is incredible noticeable in the CLI.
No idea why people think it's a good idea for corporate deployments. The whole point of a PON is that you don't have to have active elements in the field. That's usually of little consequence in a corporate or even academic campus environment. I'd just stick to active-E.
Hello
We run a small FTTH internet service provider using Zhone MXK198 switches. This is an older discontinued platform and since Zhone and Dasan merged, there might be nothing but the name in common with your equipment. Anyway, ours are stable and in five years on about 15 switches, we only have had one crash. Fixed after a power cycle.
This is however the kind of equipment that you only run tested and verified setup on. Lots of stuff does not work quite as it should, but when you find a good configuration and stay with that, it is good. There are some strange things, like vlan 7 being reserved and unusable.
When used with fs.com GPON sfp modules, it will work if the port has had a genuine Zhone sfp installed previously. However after a reboot it will reject the module. You then need to shift your genuine module through all the ports to activate them.
The switch will reject other brands of ONU/ONT. Contrary to what they tell you, this is not because of lacking standards. There is a secret setting (which I don’t have) that will make it accept third party ONU. Likewise if the ONU is programmed with the Zhone vendor code, it will be accepted.
We are currently looking at cheaper options that do not come with vendor locks for SFP and ONU.
Regards
Baldur
tir. 11. dec. 2018 16.45 skrev Nick Bogle <nick@bogle.se>:
There’s only so much space in conduits, risers and ducts. At some point, scale would press this up against physical infrastructure realities depending on how far the active gear at the head end is from the subscriber.
A point made earlier was that typically in a campus environment, most
every riser cupboard has access to power so you can easily build a
regular Ethernet LAN with a switch on every floor/corridor/hub.
Basically, everywhere that you'd put a GPON splitter.
Aled
And WDM gear if necessary...heck even passive CWDM if you have a riser space issue.
Sure but I can fit quite a lot of fiber in very little space. eg an 864 is approx 1” dia.
Fan-outs can be done each floor, etc. And a single single mode strand has prodigious bandwidth available with the right optics.
Bonus: if you did this 30 years ago, you’re still good. Anything else (remember FDDI grade Multi-mode?) is not future proof IMO. Basic 9/125 Singlemode always will be.
In city wide deployments, a bit different, especially for eg residential service at economical pricing. GPON for sure has it’s place, I just don’t personally feel it’s inside a building all else being equal.
- Ben Cannon, AS15206
And WDM gear if necessary…heck even passive CWDM if you have a riser space issue.
WDM is much more expensive than GPON.
I am still waiting for one of the 10G PON variants to become available. We want to deliver 10G to customers as >1G is becoming common on CPE Wi-Fi routers. But doing it with WDM is too expensive and p2p uses more fiber than we have.
Regards
Baldur
Passive CWDM is cheap and supports 10gig.
tir. 11. dec. 2018 19.03 skrev Ben Cannon <ben@6by7.net>:
Sure but I can fit quite a lot of fiber in very little space. eg an 864 is approx 1” dia.
Working with that much fiber is expensive. Too much work at each splice point. Huge inflexible cables. Expensive machinery to blow the fiber.
Compare that to blowing a 24f cable of 4 mm into a 6 mm id and 10 mmu od duct. You can carry 24 times 128 users on that. Much more than the 25 mm monster cable running p2p.
On top of that the multiduct has 12 of the smaller 10 mm subducts. You can blow additional cables as needed.
Granted I have only worked with outside plant delivering FTTH. But I don’t see why not for a campus.
Regards
Baldur
XGS-PON is available now from some vendors. I know of at least one that's also already supporting NG-PON2 WDM-PON using the same cards and just different optics if you really want to go all the way to 52Gbps per PON (GPON + XGS-PON + 4xNG-PON2 lambdas).
OLT-side, the pricing I've seen is actually pretty decent at maybe 2-3x the price per port of GPON despite having ~5x the capacity. ONT-side has a bit of an ouch factor at the moment (also 2-3x or more the price of a GPON ONT...), but if you've got someone who actually wants >1Gbps service and can charge accordingly, it's definitely out there.
Hi Nick,
Do I correctly understand that you're using GPON *inside* the building
for connecting stations to the wiring closets rather than connecting
the wiring closets back to campus IT central? Truly using it for the
LAN and not the campus WAN?
Regards,
Bill Herrin
Sure but I can fit quite a lot of fiber in very little space. eg an 864 is approx 1” dia.
Fan-outs can be done each floor, etc. And a single single mode strand has prodigious bandwidth available with the right optics.
Bonus: if you did this 30 years ago, you’re still good. Anything else (remember FDDI grade Multi-mode?) is not future proof IMO. Basic 9/125 Singlemode always will be.
In city wide deployments, a bit different, especially for eg residential service at economical pricing. GPON for sure has it’s place, I just don’t personally feel it’s inside a building all else being equal.
I’d actually argue that even if you’re going to do GPON on a wide distribution, the economics these days make a pretty good case for future-proofing with home-run fiber and putting your splitters and GPON gear in the same location. The link budgets turn out to be identical regardless of how far upstream the splitter is and once you dig the trench, the cost of the fiber itself is relatively cheap.
Home run means you aren’t locked into the PON topology if something better comes along in the future. It also opens up the potential to support competition (which I realize may be considered a detractor by some).
Owen
Bill,
That is correct. We are running SMF from our Datacenter to the end users desk in the building and providing either in wall 4 port ONTs or desktop 8-16 port ONTs. Everywhere there would be a traditional 3 port CAT6 network jack there is a APC fiber jack and/or an in wall ONT.
I wish this was an option… There isn’t any budget for ripping out this system and we are already contractually obliged to deploy GPON in another building that will be coming online in 2-3 years. We’ve severed the contract beyond that already.
That being said… We have ~580 ONTs (remember, we are deploying fiber to the user, not to the MDF. There is no network closet.) To deploy a Cisco compact switch or something similar would cost ~1,000/ea plus $200 minimum for third party optics, then to add a large enough fiber distribution switch for that many ports would be astronomically expensive. It was a poor desicion that will have to be maintained for the next ~25 years until the next remodel thanks to our previous non technical administration listening to the sales people over the previous network administration team.
Campus network deployments are expensive, by their very nature. You are deploying a lot of capacity over a not-insignificant footprint.
If your building has been constructed sans wiring closets, then I can forsee other issues in your future - Will you be deploying WiFi on site? If so, where do you intend to situate the Switches/ONTs+PoE injectors for those?
I wouldn’t put my name to this.
~A