Traffic jams, robberies, thefts, drugs, human traffickers, many security problems in the city! The city is not safe! Modern network governance is needed to help address these issues. Surveillance cameras need to be continuously increased, with hundreds or even thousands per block. However, it is difficult to grasp real-time, clear, high-quality video images at the first time, and fiber resources are extremely tight. The cost of laying fiber optic cables is not only very expensive, but also more difficult to coordinate. The network system laid with traditional network cables will suffer from electromagnetic interference and lightning interference, as well as a series of problems in power supply, and the reliability is not good.
Given this, how to solve the above problem?
PON network is an important realization form of FTTH. It is mainly reflected in the fact that no active equipment is required in the transmission process, which brings convenience to the cost construction and subsequent transformation of the network. Secondly, the main working mode of PON is point-to-multipoint, which will greatly reduce the laying, not only reduce the workload, but also bring greater advantages in cost and management.
The advantages of PON technology are mainly reflected in the following aspects:
- Optical fiber access network is the most suitable solution for future development, especially PON technology has been proved to be a very cost-effective way of comprehensive broadband access.
- Due to the use of PON technology, the entire optical distribution network is passive, and the passive optical network is small in size and simple in equipment. Compared with copper wire network, PON can reduce maintenance and operation cost, completely avoid electromagnetic interference and lightning interference.
- Passive devices (optical network units) of PON do not need power supply, which not only eliminates a series of problems in power supply, but also has better reliability than active devices.
- Due to the use of passive components and the shared optical fiber transmission medium, the investment cost of the entire optical network is low.
- PON is transparent to the transmission system used to a certain extent, and it is easier to upgrade.
PON technology has become the industry-recognized preferred solution for fiber-to-the-home (FTTH). The PON technology adopts a point-to-multipoint topology, and the downstream and upstream transmit data through TDM and TDMA respectively. The distance between the OLT and the ONU can reach 20km, the transmission rate is 1Gbps symmetrical in both directions, and the maximum splitting ratio generally supports 1:32 or higher. It can be split by one level or by multiple splitters.
Using PON technology can effectively solve the limitation of network monitoring bandwidth and distance. The central office OLT equipment is deployed in the central office computer room, and multi-level optical splitting is adopted to realize flexible deployment of points; ONU + network camera is used as a terminal combination, of which ONU can be a PoE switch with PON function; the central office sends upstream multicast data at the same time. to the client’s monitoring room and storage server. It can be monitored in real time in the monitoring room, and the video data can be sent to the storage server at the same time, which is convenient for later evidence collection.
PON is a passive optical network with a point-to-multipoint (P2MP) structure;
PON consists of optical line terminal OLT (Optical Line Terminal) and optical network unit ONU (Optical Network Unit)It is composed of POS (Passive Optical Splitter);
Several PON standards:
APON: ATM Passive Optical Networks
EPON: Ethernet Passive Optical Networks
GE-PON: Giga-bit Ethernet Passive Optical Networks
GPON: Gigabit-capable Passive Optical Networks
PON Technical standardization progress
GPON vs EPON
|
P2MP |
P2P |
|
|
GPON |
EPON |
|
Standard |
ITU.T |
IEEE |
IEEE 802.3ah |
Rate |
2.488G/1.244G |
1.25G/1.25G |
100M~1G |
Split ratio |
1:64~1:128 |
1:16~1:32 |
1:1 |
Bearer |
ATM, Ethernet, TDM |
Ethernet |
Ethernet |
Bandwidth efficiency |
92% |
72% |
80% |
QOS |
Very good, including Ethernet, TDM, ATM |
Good, only ethernet |
Good, dedicate bandwidth |
Optical budget |
Class A/B/C |
Px10/Px20 |
/ |
Ranging |
EqD Logical equidistance |
RTT |
/ |
DBA |
standard format |
Manufacturer custom |
/ |
TDM |
TDM over Ethernet |
TDM over Ethernet (PWE3, CESoEthernet) |
Good, dedicate bandwidth |
ONT |
OMCI |
/ |
None |
OAM |
ITU-T G.984(powerful) |
Ethernet OAM(Weak, factory expansion) |
IEEE 802.3ah |
OPEX |
Low OPEX |
middle OPEX |
/ |