Abbreviations associated with GEPON –

  • PON: Passive Optical Network
  • EPON: Ethernet Passive Optical Network
  • GEPON: Gigabit Ethernet Passive Optical Network
  • OLT: Optical Line Terminal
  • ONU: Optical Network Unit
  • POS: Passive Optical Splitter

What is GEPON technology?

EPON (Ethernet Passive Optical Networks) or GEPON (Gigabit Ethernet Passive Optical Networks), also known as Ethernet PON is an access layer technology to connect internet for the users through optical fiber. This technology is based on fiber network which renders fast data transmission and lower data packet loss. GEPON technology supports upto 20 kms. The downstream is broadcast and upstream is TDMA technology. From OLT to ONU the data packets are broadcasted and from ONU to OLT, each ONU is assigned time slots to fetch data using TDMA (Time Division Multiple Access) technology which avoid collision.

Why GEPON is called Passive Network?

It is true that the OLT and the ONU are active devices, which need power input, but logically the whole GEPON network is based on Optical Fiber network. Fiber split ratio is determined and calculated to connect number of ONUs. This fiber network is PASSIVE network, where no active power is required. Hence, majority network design is on optical fiber and thus, GEPON is called A Passive Optical Network Technology.

How many kilometres will GEPON technology support?

GEPON technology is designed to supports 20 kilometres by standard.

Why GEPON technology supports only 20kms?

The distance, GEPON supports is dependent on the split ratio of the optical fiber. Current EPON systems are designed as per 1*32 split ratio which can support upto 20kms. Further split will render shorter distance coverage. Also, it is widely dependent on the ONU optical receiving sensitivity which in general is -26 dbm. Hence, as per the technology standard calculations/specifications, current GEPON system can support maximum upto 20 kms.

Chipset used in Optilink OLTs?

There are various chipset OLTs available. With respect to Optilink OLTs we use,
OP-EOLT 97042P (2 PON Port OLT) - TK chipset
OP-EOLT 97084P (4 PON Port OLT) - Cortina Chipset OLT
OP-EOLT-97168P (8 PON Port OLT) - Cortina Chipset OLT

Chipset used in Optilink ONUs?

There are various chipset ONUs are available. We use TK, Cortina, ZTE, BroadCom and Realtek chipset ONUs.

Will Different chipset ONUs work with Optilink OLT?

ONU compatibility depends upon ONU CTC version. We have expertise in our Research and Development, which observe strong testing parameters and make the ONUs compatible with Optilink OLTs.

What if I use a different brand ONU with Optilink OLT?

As per standard, all chipset ONUs can work with Optilink OLT. We cannot assure you that other brand ONUs be compatible with our OLT.

What is CTC in ONU ?

CTC is China Telecom. It is a standard derived for the ONUs as per China government. CTC is responsible for compatibility with different devices and also networking features an ONU can support.

Why is Optilink not using same chipset for OLT and ONU ?

We offer to have a network with same chipset devices but, since every chipset has its own advantages commercially and also with respect to networking requirements, we offer variety of ONUs to chose with.

What are the devices involved in deploying GEPON Technology?

  • OLT device at the control room.
  • ONU device for clients.
  • PON SFP module.
  • POS (Passive Optical Splitter).
  • Fiber patch cord.
  • Fiber power meter.
  • A trained Fiber operation team.
  • Laptop/PC system to monitor.

What are the Different OLT configurations available?

  • OP-EOLT 97042P - 2 PON port OLT
  • OP-EOLT 97084P – 4 PON port OLT
  • OP-EOLT 97168P – 8 PON port OLT
  • OP-EOLT 97016P – 16 PON port OLT

What is the optical power output of PON SFP module, used on the OLT?

PON SFP optical out ranges from +3 dbm to +5 dbm. The range varies as per module laser individually.

Can we use +7 dbm modules in OLT?

Yes, you can use any module which supports EPON standards provided it is compatible with Optilink OLT.

How much is the OLT flash memory?

OLT flash memory is 128MB.

What kind of fiber splitter used in GEPON Network?

It is recommended to use PLC (Planar Lightwave Circuit) fiber splitter meant for GEPON technology.

Splitter RatioAverage Splitter Loss (in dB)
1*2 3.5
1*4 6.5
1*8 9.7
1*16 13.4
1*32 15.8
1*64 18.7

Can we use the fiber splitter available in cable TV network?

Yes we can use the fiber splitter used in cable TV network. We recommend to use standard PLC splitter meant for GEPON technology for better network.

Can I give fiber input to the OLT?

Yes. We have combo ports for UPLINK. You can use either fiber port or Ethernet port for input.

Can I use OLT in ring network?

OLT supports RSTP. We recommend not to have OLT in ring as ring should always be on the Switching network. OLT is an access layer device. Always redundancy has to be on switch and below each switch, OLT should be connected.

How many ONU on 1 PON port can be connected?

NO. PON port supports 64 LLID (Logic Link Identification).

What will happen if more than 64 ONU connected in the PON port?

By standard, a particular PON port on an OLT supports 64 ONUs, so 65th ONU technically will not connect/register if all 64 ONUs is online at the same time on the OLT.

How does ONU get LLID?

LLID is Logic Link ID. GEPON technology works on TDMA technology from downstream. ONUs observe TDMA technology, each ONU sends request in the prescribed time slots.

Does OLT support VLAN configuration?


Does ONU support VLAN configuration?


How many VLAN I can configure on OLT?

OLT support standard IEEE802.1 Q protocol. Optilink OLT supports VLAN1- 4094.

Can we connect Ethernet switch after an ONU?

GEPON is FTTH solution. Also GEPON is bandwidth sharing device. The number of clients connected on GEPON will fetch bandwidth from OLT. We recommend to connect minimum user after ONU for best FTTH solution and to have network free from bandwidth choking.

Can I configure router configuration on ONU?

Yes, ONU comes in 2 different modes, as Bridge mode and Router board mode. You can configure static IP, DHCP and PPPoe config on ONU with router board. Here we ask you why? You are losing on to some important factors in your network. To know the factor please contact our respective sales representative. We are happy to help you.

Can I use ONU for Lease line plans?

Yes, ONU port is of 1GE. You can assign 2Mbps, 10Mbps and much higher plans on ONUs. You can also assign 100Mbps Broadband plans.

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