PON manufacturer interoperability topics: how to fix?

PON IOT issues technical discussions

  I realize the actual question is quite old. But, the below might help someone…

  • How are you planning to configure the ONT? OMCI or TR-69?
  • If by TR-69, then an ONT with compliance (needs certification) to TR-247 will be the best one.
  • If by OMCI and you have compatibility issues, then surely, one of the vendor is breaking (or mis-interpreting) the G.984/G.988 standards.
PON Network IOT Analysis

PON Network IOT Analysis

ONT strict adherence to OMCI standards & TR-247

Having direct/in-direct participation in multiple inter-op events, I can say that Alcatel-Lucent’s (my employer) “new” ONT’s performed quite well across multitude of various (Huawei, ZTE, FiberHome, Alcatel-Lucent, etc) OLT vendors. These “new/latest” ONT’s from ALU have pretty strict adherence to OMCI standards & TR-247.

Incompatibility between OLT & ONT gave rise to a new market

You are right. All or most ONTs have no issues with other OLTs when things are within the scope of L2-OCM model. Problems arise when the feature set desired by the service provider goes beyond L2-OCM. Yes, having a tool to validate the compatibility in-house first provides an advantage. Interestingly, this incompatibility between OLT & ONT gave rise to a new market in itself. We now have tools/emulators/simulators from various companies like: TraceSpan, MT2, Technalia, etc.
OMCI spec in itself is pretty vast and add to it that it is continuously evolving. Am quite not sure how much up to speed the tools from above mentioned companies are.
PON vendors compatibility issues

PON vendors compatibility issues

GPON protocol analyzer market

It is great that you are very aware of the GPON protocol analyzer market. In fact, I am working for one of the aforementioned companies (GPON Doctor of Tecnalia).
Being said that, I can guarantee that our tools are always updated to the last OMCI spec version (otherwise our customers will not be able to get the complete picture of what is going on inside their PONs).

BBF.247 certification program from BroadBand Forum

For GPON functionality and interoperability, the BroadBand Forum has produced 2 test plans: the BBF.247 certification program which specifically tests GPON ONT/ONUs compliancy to the GPON (mostly OMCI) standards, and the recently approved TR-255 interoperability test-plan for interoperability between an OLT/ONU pair. 
BBF.247 certification is provided by an independent approved laboratory (the LAN) and there are also approved laboratories for TR-255. It seems at least some SPs are starting to leverage such test plans, as it provides a guarantee of maturity for the devices.

About the tools, there are emulators and analyzers

Emulators emulate the OLT side, to stimulate the ONU (for BBF.247, according to standardized OMCI sequences), while analyzers are more of a generic protocol sniffing/debugging kind of tool. Specifically for BBF.247 an independent emulator is needed — the analyzer is optional. 

Basic OMCI service & configuration

We′ve started some GPON interop tests and we′ve reached partial success. Basic service (single VLAN bridge) configuration through OMCI runs ok, but I′ve met MTU (maximum transmission unit). On OLT-ONT of the same vendor (Huawei) we get 1472 bytes maximum payload (1514 bytes full Ethernet frame), when testing with with other vendor, I got 1468 bytes (1510 bytes full Ethernet frame).

I believe all will depend of the OMCI configuration applied by the OLT to the ONU (ie the OMCI messages sequence that is exchanged between the OLT and ONU). There might be an OMCI interop issue in the different vendor case, as this is the OMCI layer that tells the ONU how to process the incoming traffic (filtering rules).”

IOT test demo (Register ONT)

IOT test demo (Register ONT)

Additional data would be helpful to analyze:

  • the type of the applied and the expected traffic at the V and the U interfaces (ie the OLT and the ONU inputs)
  • wireshark logs and/or traces of the traffic for both cases (same vendor & different vendor)
  • the OMCI messages exchanged to analyze what the applied architecture or configuration
Note that all these items and traces could be obtained from a G-PON analyzer.
Note that a good way to avoid such issues is to make your OLT and ONUs pass the G-PON testing program from the Broadband Forum (especially BBF.247 certification).

Other tips to fix this PON incompatibility

We have tested Huawei OLT with some other vendor ONTs, in some OLT versions, they work, but in some versions, ONTs can not be registered. Also we have met challenges in VLAN. 
In our experience the compatibility depends on the OLT firmware. We have customers that bought Huawei OLTs and requested specific compatibility with their existing ONTs from other brands and they received a FW version that is easy to interact with. In other cases where all the equipment was purchased from Huawei from the beginning the OLT is not compatible with other brands.

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