Take these two articles, and then we 'll talk about GPON.
GPON is still a TDMA system that inherits OAM mechanisms such as APON/BPON dynamic bandwidth allocation. GPON uses a 125μs fixed-length frame structure of 8,000 frames per second. A TC frame can contain multiple ATM cells and GEM frames. GEM is a proprietary adaptation protocol defined by GPON and originates from GFP's universal frame idea.
Compared with other PON technologies, GPON has many advantages: First, it has strong multi-service support capabilities, which also reflects the operator's efforts to protect the original network investment. GPON has a natural adaptability to TDM business signals because it uses a mode of 8,000 frames per second and a 125μs frame length, which is exactly the same as the SDH frame. It is the basic format of TDM, so it is almost seamlessly adapted to TDM, and the jitter and delay indicators are easy to satisfy; The second is the high rate, the uplink rate of 155 Mbids ~ 2.5 Gbits, and the downlink rate of 1.25 ~ 2.5 Gbit/s: The third is the high transmission efficiency, and the physical layer of the GPON system uses the spoiler code as the line code. Its mechanism is the same as that of SONET/SDH. Since only the code is changed and the code is not added, there is no bandwidth loss for the line code and the transmission efficiency exceeds 90 <UNK>.
GPON is an ITU-T Gibet-class passive optical network. It was introduced by ITU-T after the APON standard. Therefore, the GPON G. 984 series standard inevitably follows many of G. 983's ideas. Both GPON and EPON are Gibbet-class PON systems. Compared with EPON's simple principles, GPON pays more attention to multi-service and QoS guarantees and is therefore more favored by operators. However, due to the complexity and late development of the GPON standard, its cost is relatively high