Hello everyone,
Today, I will continue to write about the PON system overview. Now, I will write about the main component in the PON system - OLT.
OLT is an abbreviation for Optical Line Terminal. It is the main device of the PON system. It enables the connection of a large number of users or ONU devices on the one side and the connection to the WAN/MAN network on the other side. OLT is connected to the core network via control boards, for connecting to the ONUs, OLT uses service boards and ODN. In this way, services are provided to subscribers.
The main functions of OLT are:
PON core functions. It is composed of framing, media access control, OAM (Operations, Administration and Maintenance), DBA (Dynamic Bandwidth Assignment), PDU (Protocol Data Unit) delimitation and ONU management;
cross-connection function. This module enables a channel between the PON core functions module and the service functions module. And,
service functions. It enables conversation between the PON TC frame interface and the service interface.
Figure 1. Block diagram of OLT
Figure 2. Huawei’s OLTs MA/EA 5800 and EA 5801
Huawei has different OLTs: MA 56xx, MA/EA 5800 and MA/EA 5801. OLT MA/EA 5800-X17 and MA/EA 5800-X15 are large capacities, for 17 and 15 service boards, respectively. The next OLT MA/EA 5800-X7 is medium capacity and the small capacity OLTs are MA/EA 5800-X2 and EA 5801. The same situation is with the older series of OLTs MA56xx.
Figure 3. OLT MA/EA 5800 – X2, X7 and X15
Most of these OLTs in the chassis have two slots for power boards (main and redundant board), one slot for FAN module, two slots for control boards (active and standby), and slots for service boards (from 2 service boards for MA/EA 5800 to 17 service boards for MA/EA 5800). The universal interface board is a part of MA/EA 5800-X17, MA/EA 5800-X15 and MA/EA 5800-X7. There is one slot for this board.
OLTs use -48 V for power supply. OLT MA/EA 5800-X2 has two DC power inputs or one AC power input. The smallest OLT - EA5801 has AC/DC optional.
They
are installed in a 19-inch frame, only OLT MA/EA 5800-X17 requires
21-inch frames.
For more information about OLT >> OLT.
I will continue to write about this topic in the next article >> PON system overview (4): Control and service boards.
Thank you!
