Users bandwidth hot discussions of PON

CATV FTTH Triple Play solution scenarios

CATV FTTH Triple Play solution scenarios

What is the each channel bandwidth availability in GEPON??? Each ONU connected to OLT will get 1.25 Gbps or not??

Discussion 1: Depend on PON port capacity and splits

It depend on PON port capacity and number of splits.

Discussion 2: PON line rate discussion

GEPON line rate is 1.25 Gb/s in each direction. Block coding reduces the usable bandwidth to 1.0 Gb/s. MPCP overhead further reduces usable bandwidth, particularly upstream. The resulting usable capacity of the channel in each direction is statistically shared amongst all ONUs on the PON.

It is fair to say that frames are sent at instantaneous rate of 1.0 Gb/s. Each ONU will be able to burst at a peak rate approaching to 1Gb/s. Worst case, each ONU should achieve sustained rate approaching (1-x)/N Gb/s where N is the number of ONUs on the PON and x is the overhead, in Gb/s. That worst case would occur only when all ONUs are sending or receiving at the same time, which is a very low probablity event.

Discussion 3: How about the EPON + EoC coaxial cable network?

In old building upgrading project, in order to make full use of the current coaxial cable network and save cost, then what will be the suituation?

Discussion 4: Think about if configured with different bandwidth

In some vendors, support 1.25G for Uplink and 2.5G for downlink traffic in each PON port. This bandwidth is sharing between the differents ONUs position in the PON port. And each ONU position can be configured with different bandwith until the PON port capacity (1.25G uplink/2.5G Downlink) is completed.

Discussion 5: GEPON and GPON different standards

2.5 Gb/s downstream is not formally a part of the GEPON standard, but it makes perfect sense for GEPON vendors to use GPON photonics. My understanding is that IEEE 802 and 802.3 (the parent committees) has been fairly dogmatic about maintaining consistent line rates that are integer powers of 10, and about symmetry (although they have made rare exceptions).
GEPON and GPON are not like TDM. You can safely oversubscribe PON ports.

Discussion 6: Sharing a actual PON application case

GEPON(we also called EPON) uplink/downlink is 1.25G. But in real project, it’s about 1G, and each users bandwidth depend on your ratio and priority.
For example, if using 1:32 with same priority, then each user will have about 31M if all users are online. Surely you can give some user 60M, and some with 20M.

Discussion 7: check ONU/ONT throughput

I would suggest to check ONU/ONT throughput too. And available backhaul capacity.
FTTH Triple Play products

FTTH Triple Play products

 –More discussions, welcome to share your ideas…

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