With the continuous improvement of network bandwidth and the continuous development of terminal equipment, high-definition video conference, cloud services, massive data exchange, mobile office and so on, make enterprises become more efficient and more open platform, so as to promote the intelligent and Information Office of enterprises, and the requirements of network bandwidth and speed are also higher and higher. The traditional enterprise and park LAN are facing these applications When the bandwidth challenges, there are demands for network upgrading; then the traditional generic cabling system has gradually failed to meet the needs of the times after nearly 30 years of rapid development; the infrastructure network construction of large-scale parks and buildings mainly faces the following challenges:
 

·A large number of switches occupy the space of the computer room, which has high power consumption and difficult heat dissipation
 

·The connection between convergence routers is complex, and takes up pipeline space, which makes routing and maintenance difficult
 

·Switch location is scattered, management is complex, and requires a large maintenance team
 

·Limit of transmission distance
 

·The operation of new network equipment is complex
 

·Difficult to upgrade and expand
 

In terms of transmission distance, smooth network upgrade, high reliability, flexible networking, easy deployment, simple operation and maintenance, the traditional generic cabling system has completely lagged behind all-optical network (POL). The all-optical network integrates the transmission of traditional generic cabling and optical fiber to desktop, optical fiber to user unit, and optical fiber to public area. In addition, network equipment is added to the original 3 Layer network becomes a flat two-layer architecture. All optical network (POL) network converges with Park + edge cloud. Enterprises can integrate different systems such as data, voice, video security and wireless into one optical network, which has incomparable advantages over traditional generic cabling.

 

Composition and transmission mode of all optical network
 

PON (passive optical network) is a point to multipoint (p2mp) passive optical network, which consists of three parts: OLT, ODN and ONU

 

POL： Passive Optical LAN
 

In the pol network, the convergence switch in traditional LAN is replaced by OLT; the horizontal copper cable is replaced by optical fiber; the access switch is replaced by passive optical splitter; ONU provides two / three layer functions to access users' data, voice and video services through wired or wireless.
 

The downlink of PON network adopts broadcast mode: the optical signal sent by OLT is divided into multiple optical signals with the same information by optical splitter and transmitted to each ONU; ONU selectively receives its own message according to the label in the message, and discards those with inconsistent marks.
 

Uplink direction of PON network: OLT side uniformly allocates a time slice to each ONU. ONU sends signals in strict accordance with this time slice window, and the optical port is turned off by its own time slice. The scheduling mechanism of uplink time window highly depends on the ranging technology of PON.
 

The understanding of PON technology principle is helpful for us to apply this technology more skillfully in electrical design, especially the passive (no power supply) characteristics of optical distribution network and the difference between traditional switch and point distribution design should be paid attention to. In order to ensure the forwarding of two direction traffic packets on one core optical fiber, PON adopts wavelength division mode; after developing to 10 Gigabit PON, four wavelength segments are actually used for optical fiber multiplexing.
 

Super long transmission capability of Pol network
 

Pol adopts hub spoke structure, while switch is multi-layer tree / star structure. In general, pol optimizes the basic wiring and network structure of LAN, and the network structure is more flat and concise.

 

The maximum transmission distance of ODN is up to 20km, which is far more than the transmission distance of traditional generic cabling. For the network construction of large buildings such as parks, airports, gymnasiums and super high-rise buildings, the traditional generic cabling needs to add additional active equipment and space to deploy network facilities to make up for the shortage of transmission distance, while all-optical network (POL) network reduces the same number of active equipment Can easily solve difficulties.
 

The easy deployment property of Pol network
 

Traditional generic cabling system needs weak current room, cabinet, power supply and other supporting facilities when deploying access switch, while all-optical network (POL) does not need special weak current room; the splitter can be flexibly arranged according to the user's site environment without supporting facilities such as weak current room, cabinet and power supply; the active equipment is concentrated in the central machine room and terminal user side, so that the operation and maintenance points are more centralized Zhonghe is closer to users, making operation and maintenance more simple and efficient.
 

The ONU is pre configured according to the deployment plan. When the ONU hardware installation is completed and the system is powered on, OLT can automatically discover and add ONU, complete ONU equipment deployment and remote soft tuning, greatly improving the deployment efficiency and reducing the network construction cost.

 

Because pol breaks through the limitation of 100m distance of twisted pair in traditional generic cabling network and the demand for weak current room, and simplifies the three-layer network topology structure into two layers, thus saving 80% of the weak current room space and 60% of the power supply energy consumption, reducing the network construction cost by 30%, and reducing the network operation and maintenance expenses by more than 60%.
 

The upgradability of Pol network
 

At present, according to the traditional generic cabling system, the network service life is about 10-15 years, and the system is gradually eliminated in the application process. However, with the rapid development and popularization of intelligent buildings and the Internet of things, we have to re-examine the continuous availability of network construction. In the future, terminal access equipment will grow exponentially, bringing huge pressure on bandwidth. The traditional generic cabling system does not All optical network (POL) network optical fiber can provide GPON, 10gpon, 50gpon / 100gpon bandwidth and speed for smooth upgrading, so that the network service life of the park and buildings can be prolonged by multiple times, ensuring the network availability, and maintaining the network foresight.

 

The speed of equipment iteration is a major problem in network construction. The old equipment can only be discarded, which will lead to a huge waste of assets. However, all optical network is based on optical fiber network, which can meet all kinds of broadband requirements in the park. For example, the current popular Wi Fi 6 service needs 2.5Gbps or 10gpbs service interface, corresponding to 10g PON solution or 50g PON can be easily carried with large uplink bandwidth. The upgrade of all-optical networking network only needs to replace the board card or even replace the optical module. In addition, the optical fiber has the characteristics of corrosion resistance, high and low temperature resistance and anti-interference. The service life of Pol all-optical network can be up to 30 years. The ultra long network service cycle can optimize the investment cost in the whole life cycle of the network.
 

High reliability of Pol network
 

Pol adopts PON solution architecture, OLT is deployed in the core computer room. From the core computer room to the user, the middle layer adopts passive optical splitter, which does not need independent machine room deployment and power supply. It reduces the fault points of active equipment in the middle. ONU is close to users and connects users through copper wire. Pol all-optical network is widely used in large and medium-sized enterprises, government agencies, science and technology parks / industrial parks, schools, hospitals, as well as various scenarios in which local area / local broadband networking is needed. According to their business needs and networking scale, pol all-optical networks are widely used.
 

Pol ensures the continuous availability of the network through a variety of networking methods, as shown in the following figure:

 

Security protection of Pol network
 

Pol network effectively avoids electromagnetic interference, electromagnetic leakage and other issues, supports AES 128 encryption to ensure the security of data optical fiber transmission; POL equipment supports MAC binding, 802.1x authentication, user isolation, broadcast suppression, and prevents DoS attacks, effectively eliminating illegal user access and other user attacks.
 

·Support port and ONU isolation function
 

·Support MAC filtering
 

·Support DoS attack prevention
 

·Support user classification to prevent unauthorized user's intrusion
 

·Support port broadcast / multicast packet suppression
 

·It supports flow classification and flow definition based on source / destination MAC address, VLAN, 802.1p, TOS, diff serv, source / destination IP (IPv4 / IPv6) address, TCP / UDP port number, protocol type and other IP header information
 

·Support L2-L7 ACL stream classification with depth of 80 bytes in header
 

·Support business flow policies, including mirroring, redirection, statistics and filtering
 

Andre kindness, chief analyst of Forrester, pointed out in his speech that pol PON uses optical fiber to reconstruct the traditional campus network, extending the optical fiber to the last meter, highly matching the demands of deployment, maintenance and evolution. With the fast development of IFNET, the network will grow more efficiently and more efficiently in the future In the new era, F5G has become the best choice for digital transformation of education, Anping, hotels, government, transportation, factories, comprehensive parks (intelligent buildings, commercial complexes, residential communities and industrial smart parks).