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title: "Provincial Political-Legal Broadband Fiber-Optic Information Communication Network"
industry: "Enterprise"
images:

• "/images/imports/img-fc1d6bd5.jpg"
• "/images/imports/img-b0386730.jpg"
• "/images/imports/img-6e80eb8b.jpg"
  brief: "The third-level and fourth-level communication networks of the XX Provincial Public Security Bureau have undergone multiple upgrades, from leased DDN and E1 channels between county bureaus and police stations to a PDH 100M fiber-optic communication network. With the construction of the Skynet Project, increasing transmission bandwidth is required, and the fiber-optic transmission bandwidth is now being upgraded to achieve multiple line-rate Gigabit Ethernet transmissions. Due to the confidentiality requirements of the public security private network, several Ethernet networks with different functions require physical isolation and must achieve line-rate 100M or 1000M. Among the public, procuratorial, judicial, and law-enforcement agencies in the political-legal system, only the public security bureau has its own technical capabilities to establish its own communication system in its own equipment room. In other provinces, relying on the public security bureau's infrastructure, a dedicated communication network for the public, procuratorial, judicial, and law-enforcement systems is built, providing each system with its own physically isolated Ethernet network while sharing the Ministry of Public Security internal telephone system of the political-legal system. Currently, in XX Province, apart from the public security system, other political-legal systems generally use operator VPN private networks for data transmission, which is relatively single-purpose, weak in confidentiality, and not conducive to business expansion."
  slug: "fiber-communication"
  publishDate: "2015-05-05"
  featured: false

一、 Current Status

The third-level and fourth-level communication networks of the XX Provincial Public Security Bureau have undergone multiple upgrades, from leased DDN and E1 channels between county bureaus and police stations to a PDH 100M fiber-optic communication network. With the construction of the Skynet Project, increasing transmission bandwidth is required, and the fiber-optic transmission bandwidth is now being upgraded to achieve multiple line-rate Gigabit Ethernet transmissions. Due to the confidentiality requirements of the public security private network, several Ethernet networks with different functions require physical isolation and must achieve line-rate 100M or 1000M.

Among the public, procuratorial, judicial, and law-enforcement agencies in the political-legal system, only the public security bureau has its own technical capabilities to establish its own communication system in its own equipment room. In other provinces, relying on the public security bureau's infrastructure, a dedicated communication network for the public, procuratorial, judicial, and law-enforcement systems is built, providing each system with its own physically isolated Ethernet network while sharing the Ministry of Public Security internal telephone system of the political-legal system. Currently, in XX Province, apart from the public security system, other political-legal systems generally use operator VPN private networks for data transmission, which is relatively single-purpose, weak in confidentiality, and not conducive to business expansion.

Building the systems together not only saves communication equipment rooms, communication equipment, and reduces maintenance personnel, but also enables the use of the same fiber core, saving fiber line rental costs. Generally, public, procuratorial, judicial, and law-enforcement agencies at the township level are usually located in the same compound or not far apart. In 2010, the Hebei Provincial Political-Legal Network organized a provincial bidding to uniformly procure equipment for municipal political-legal networks. Township-level judicial units were provided with Ministry of Public Security internal telephones and telephone numbers from the same exchange prefix as the political-legal system's local telephone network, which not only unified the external image but also facilitated centralized management. As this system was built relatively early, the transmission bandwidth generally used a 155M SDH ring network system, leaving limited reserved bandwidth for Skynet Project video transmission. Later bidding regions adopted a 622M SDH ring network system.

二、 Recommended Structure for the Fourth-Level Network

In this fourth-level network upgrade, the central end is equipped with SDH ring network protection interface aggregation, and can access the public security telephone switching network and the local telephone switching network via No.1, No.7, and PRI signaling. Point-to-multipoint multi-Gigabit fiber access equipment is adopted for each township.

Since video big data storage, processing, and server processing can be placed at the county bureau, while townships have weak technical capabilities and limited equipment room conditions, only the links from county bureaus to townships require multiple line-rate Gigabit network transmissions. The county bureau to municipal bureau links use 622M SDH ring transmission for processed video big data, as well as the public security internal network and video conferencing.

The fiber-optic transmission system upgraded in this fourth-level network of the XX Provincial Public Security Bureau adopts a 2.5G or 5G transmission rate, providing 2 or 4 line-rate 1000M physically isolated Ethernet channels over the fiber, meeting the high-bandwidth requirements from county bureaus to townships. This large-capacity bandwidth also provides ample channels for video transmission, including video conferencing and video surveillance.

2.5G optical transmission offers longer transmission distances than 5G optical transmission. Typically, optical transmission above 5G has a distance of generally less than 10KM, and expensive optical amplifiers are required for longer distances. 2.5G, however, can typically transmit over 20KM, 40KM, 60KM, etc.

Currently, each county conducts bidding separately, with inconsistent technical requirements. Telephone access still uses FXO and FXS distribution frame access methods, resulting in high costs, multiple failure points, and low telephone switching efficiency. In bids such as the Hebei Political-Legal Network, remote telephones are required to be aggregated and connected to the public security telephone access system via China No.1 signaling, and to the local operator telephone network via China No.7 signaling and PRI signaling.

Additionally, adopting standard SDH technology allows direct access to the operator's telephone switching system.

In some important locations, fiber loop protection is also required, meaning that if one fiber break occurs on the fiber loop, all devices can still continue communicating in a chain network. Although some locations do not use ring networks, dual optical port backup is required on the fiber interfaces.

Providing high-definition video interfaces in fiber-optic equipment is very convenient.

三、 Public Security Checkpoint System

Nowadays, public security agencies across the country have established public security convenience kiosks, which should be connected to the public security internal information network and the public security internal telephone system. At the same time, to facilitate public service, Internet access and local telephone services should also be provided. That is, 2 physically isolated Ethernet channels and at least 2 telephone lines should be provided; some require two networks: a road surveillance network and a public security internal office network. Typically, 1 bidirectional video channel is also required for simple video conferencing.

Our company's NTD421 is a data terminal with a fiber line rate of 250M, capable of providing the above services. It can be used in point-to-point pairs or connected to the upper-level network via the GP_MPconv device. The GP_MPconv is a device that can be used standalone or inserted into our company's G3CP integrated service platform. It also provides 2 telephone line accesses and 1 RS485 channel access.

When the number of remote NTD421 units is small, they can also be accessed by inserting the GPuser card into the MP200 optical interface card on the G3CP.

Additionally, our company's GTD441 is a device with a 2.5G fiber line, capable of outputting two groups of line-rate Gigabit interfaces (each Gigabit group consists of 1 optical port and 1 electrical port, which can be switched), with dual optical ports supporting mutual backup; it can also form a chain network or ring network, where the 2 Gigabit electrical ports and the optical port are on the same Gigabit channel and can switch with each other, while the other Gigabit channel passes directly between the optical ports. The GTD441 also provides 4 telephone line accesses and 1 RS485 channel access.

The GTD441 can be accessed by inserting the GPuser card into the GP2000 optical interface card on the G3CP.