Before explaining what an OLT is, first we need to talk about what a PON (Passive Optical Network) is.
A PON network is a network that uses fiber optics with optical splitters (splitters) along the way to provide data from point to multipoint, that is, on one side a light beam passes through a splitter and is divided into it. for n paths, without needing electricity on the path, only in the emitters at the ends (OLT and ONT/ONU):
What are the main advantages of a PON network?
As mentioned above, there is no need to have assets on the route, which would consume electricity.
Other advantages are, as it is formed with optical fiber, we do not have the risk of burning the equipment due to an electrical discharge passing through the cable, it supports high speeds, it does not suffer from electromagnetic interference, as it does not conduct electrical signals, but light, therefore, insulating , less attenuation with distance, that is, they can go further than metallic cables, have less deterioration, greater safety and lower maintenance costs.
Now yes, what is an OLT?
OLT is the brain of the entire PON network, it is the one on the side of the internet provider, it is the one who commands and manages the PON network, it is the one who determines the time, the sending band of each ONU and the priority of each service .
In short, it is the OLT that defines the services, their amount of bandwidth and priority for each one, in the ONUs, sending parameters such as the VLANs and their respective interfaces, if the port will be “transparent” or in “tag”, etc.
The OLT can also send extra parameters to the ONUs, such as which ports will perform NAT, if the ONU will be PPPoE, DHCP, Bridge and etc… even Wireless parameters, however these extra parameters, outside the definition of the protocol, generally only work integration when the OLT and ONU are from the same manufacturer, since each one ended up doing it their own way.
What is an ONT (Optical Network Terminal) / ONU (Optical Network Unit)?
ONT or ONU are the equipment at the end of the PON network, which receive the orders from the OLT, it is the equipment that is generally located in the subscriber’s home (FTTH), in the building (FTTA) or in the Company (FTTB).
There are several types of ONUs from different manufacturers such as Huawei, Fiberhome, Datacom, Intelbras, Nokia, Zhone, DasZhone, Furukawa and many other manufacturers and all are theoretically compatible with any OLT, as long as the protocol used is the same in both.
Can a Huawei OLT send the PPPoE configuration to a Fiberhome ONU?
It is unfortunately not possible, what it can send are parameters defined in the protocol, such as which VLANs the ONU will have and their respective interfaces.
Some OLT support this, but in the example between OLT Huawei and ONU Fiberhome it does not.
Can a Huawei, Fiberhome or Datacom OLT send extra parameters to ONUs from the same manufacturer, such as PPPoE login and password for the ONU to dial, SSID and wifi password?
Generally yes, each one ended up defining its structure to be able to send this type of extra information/configuration to the ONU.
But how do I go about uploading PPPoE between different manufacturers?
One option would be, as VLAN parameters are included in the protocol standards, just activate the ONU in the OLT as if it were a bridge, put the VLAN you want and in the ONU add the extra parameters manually (configuring through the Web interface for example), in the if the subscriber’s PPPoE, Wi-Fi settings and etc.
But of course, there are other ways to carry out this type of configuration, such as TR069, which our Made4Graph system also has, so imagine, if for some reason the ONU resets, how will it raise the PPPoE parameters again? If the OLT does not have this information (in this case), either we will have to have another protocol sending these parameters, in this case TR069, or we will have to manually upload the ONU interface.
Which OLT manufacturer should I choose and which one is the best?
There is no better or worse, but the answer is It depends on your scenario and network.
Our recommendations are:
- Always use the same manufacturer of ONU/ONT and OLT. Some manufacturers tend to have more difficulties than others, but in general what we recommend is to use as much ONT/ONU from the same OLT manufacturer as possible, this guarantees full support and integration, and in case of any anomaly and you need support from it , avoid things like “We don’t support this UN. It’s the fault of a third party UN” and etc…, even though there are rules for this communication.
- Look for products approved by Anatel, this guarantees that at least the equipment has been tested.
- There are OLT manufacturers that block third-party ONUs and some even block specific versions or models, so it is interesting to have this information before purchasing OLT and ONUs.
- Check if it exists and how is the support of this OLT in Brazil, after all, when the “bug catches” we have to have a good support to help us.
- Check the equipment manufacturer’s documentation. Some manufacturers provide manuals, configuration examples and/or usage implications, with all this information it makes it much easier for the operations team or for your IT/CGR/NOC to deploy the new equipment. Always look for equipment that has good documentation.
- Find out about the limits of this equipment and its boards, if the resources they have will meet your current and future needs, so you don’t have to change the equipment so soon.
But I will comment on my experience with some of the most well-known OLT manufacturers:
- Excellent performance and stability
- They don’t have direct support here in Brazil yet, so the language can be a difficulty, but if you have a good supplier, he can help with support
- Excellent documentation
- Does not support 3rd party ONUs natively, however there are release to accept ways (Not recommended by manufacturer)
- Great and stable performance
- The support is excellent and made in Brazil
- Supports 3rd party ONUs natively
- Great documentation
- You can buy directly from Datacom
- Widely used by ISPs in Brazil
- Supports 3rd party ONUs on some firmwares
- It has support from Brazil
- Little documentation or difficult to find official information
- It works well if you use Fiberhome’s ONU
It is a simpler OLT, with few PON ports, but it works well in smaller environments and networks
- There is no official support in Brazil
- Supports third-party ONUs
- Good option for simple scenarios
- Low cost
Doubts remain? Get in touch with us and we’ll help you as best we can 🙂
Zanclair Ferrari Junior | Network Consultant
JNCIS-SP | CCNA | HCIA | MTCRE