Hello, everyone!
Today, I will explain old PON technology – BPON. The first technology was APON (ATM PON), the next technology was BPON. BPON is a similar APON, but this technology has extra functionality. This is a brief history of PON.
BPON is an abbreviation from Broadband Passive Optical Network. It was the second PON standard. This technology uses ATM as a signaling and transference protocol. BPON technology is based on the ITU-T G.983 standard.
ITU-T G.983 standard defines:
speed in downstream and upstream,
data, voice and video control functions,
adding wavelength for video,
security features, and
DBA (Dynamic Bandwidth Allocation).
In the next figure, we can see the architecture of the BPON.
BPON is composed of OLT (Optical Line Terminal), ODN (Optical Distribution Network), and ONUs (Optical Network Unit). The maximum distance between OLT and ONU is 20km and the maximum PON splits is 32.
BPON ATM signals operate at 155, 622, and 1244 Mbps. Signals for data and voice are 1490nm for downstream and 1310nm for upstream. Data packet cell size is 53 bytes. The maximum speed for downstream is 1.2 Gbps and the maximum speed for upstream is 622 Mbps.
Video signal is an analog modulated signal, and there are separate pieces of equipment for this segment of the system. The devices are optical transmitter 1550nm and optical amplifier – EDFA (for detailed information you can see my article EDFA). We can use any modulation technology for video: QPSK, 64QAM, 256QAM, etc.
The next table shows us the main features of BPON technology.
Standard | ITU-T G.983 |
Data Packet Cell Size | 53 bytes |
Max speed | 1.2 Gbps for downstream 622 Mbps for upstream |
Traffic modes | ATM |
Voice | ATM |
Video | 1550 nm |
Split Ratio | 16 or 32 |
Reach | 10-20 km |
Fiber Type | G.652 |
Power Budget | Class A: 5 – 20 dB Class B: 10 – 25 dB Class C: 15 – 30 dB |
Transmission | Single fiber |
BPON offered high-speed and triple services (data, voice, and video). But BPON was not widespread. One of the biggest advantages was the low cost of maintaining the network. After that, BPON had flexible and scalable traffic management.
Thank you!
