1, the current situation of the communication network and construction background

Beijing-Shanghai Expressway (Hebei section), as an important part of 104 National Highway and Hebei Provincial Expressway Network, its communication system is not only responsible for the data, voice and video communication of this expressway, but also lays the foundation for the establishment of Hebei province's network charging and the province's communication network.

As early as in 2002, the Beijing-Shanghai Expressway set up and opened the first set of communication system, in which the fiber optic digital transmission system adopts SMA series2 2nd generation synchronous multiplexer produced by Siemens Guangzhou, with a transmission rate of 622 Mbit/s; the integrated service access network system adopts ULC-1000AN (OLT, ONU) produced by Taiwan Rongqun Telecom Co. The integrated service access network system adopts ULC-1000AN (OLT, ONU) equipment manufactured by Taiwan Rongqun Telecom Co.

In recent years, in order to meet the development requirements of broadband data, NGN, 3G and other comprehensive services on the survivability and expandability of the transmission network, as well as the realistic needs of the province's networked toll collection and the construction of the province's communication network, most of the newly-built or reconstructed high-speed road sections in Hebei Province have adopted Huawei's Optix Mertro 3000/2050/1000 series of equipment to set up the SDH transmission system, so that a technologically advanced, integrated and strong network can be built up, with a high speed and high quality. This has resulted in the construction of a technologically advanced, highly integrated and high-efficiency transmission platform. Therefore, in order to realize a "seamless" connection with adjacent road sections and centralized management of the province's network layer, it is imperative to carry out a technical transformation of the existing communication system of the Beijing-Shanghai Expressway.

2, OSN intelligent optical network equipment features

OSN intelligent optical network equipment is an ASON-basedMSTP (Multi-Service Transmission Platform) platform launched by Huawei Shenzhen in October 2003, which is a future-oriented device. Ultimately, it can realize fast service service and dynamic bandwidth management for the entire network at the optical and customer layers end-to-end, and the whole network is intelligent: it supports end-to-end service configuration; it supports auto-discovery of optical fibers and service links; it supports Mesh grouping protection, which strengthens the network's survivability; it supports differentiated services, and it can decide on the required protection level according to the service level of the signals at the customer layer It supports traffic engineering control, and the network can be dynamically adjust the logical topology of the network in real time according to the service requirements of the customer layer, realizing the optimal configuration of network resources. It is both the inheritance and the development of traditional SDH services. Therefore, it can completely group the network together with the equipment in the existing network, which not only reduces the investment, but also realizes the requirements of intelligent development of the network, which is mainly reflected in the following aspects.

(1) Inheritance of MSTP Characteristics

OSN series products inherit the leading MSTP features of Huawei's Metro series products, including GFP encapsulation, full-particle virtual cascade and LCAS, MPLS, and RPR, etc., and have been enhanced in some aspects, such as realizing pure RPR networking, and also coexisting with traditional network networking methods to enhance network robustness. It can build a unified MSTP platform with Metro series equipment, provide flexible and changeable service carrying capacity and networking scheme, and achieve unified management of the whole network and end-to-end scheduling and generation of data services. In terms of hardware, OSN series equipment is a cost-effective series platform, superior scalability to maximize the protection of user investment, business boards are fully compatible, constituting a unified platform; 2.5Gbit/s system can be smoothly upgraded to 10 Gbit/s system, STM-1/STM-4 can be smoothly upgraded to 2.5Gbit/s system; and has the ability to upgrade to 10 Gbit/s system, 2.5Gbit/s system, and 2.5Gbit/s system. Gbit/s system; and has a small size, low power consumption; free testing, optical modules can be plugged and unplugged on site; optical power detection, software package loading and other rich maintenance functions. This not only reduces the investment, but also reduces the difficulty of maintenance and saves maintenance costs. Adopting multi-ADM design for high-capacity high-low-order scheduling, OSN3500/OSN2500/OSN 1500 support 15/12/12 service slots respectively, providing powerful multi-service access, aggregation and scheduling capabilities, which can be applied in the access layer (e.g., OSN1500 and OSN2500 ), aggregation layer (e.g., OSN3500 ), backbone layer (e.g., OSN7500 and OSN2500), and backbone layer (e.g., OSN3500 and OSN3500). OSN7500 and OSN9500).

(2) Introduction of intelligent features

Supports automatic discovery of fiber optic and service links. When the fiber optic of the whole network is correctly connected, the network manager can automatically search for the fiber optic and create all fiber optic links at once. Auto-discovery of link topology enables fast end-to-end service configuration (SPC/SC), shortens service establishment time, and realizes dynamic application and release of bandwidth; Mesh rerouting with path recovery/link protection enhances network survivability and improves bandwidth utilization; Recoverable rerouting design is conducive to network optimization; Real-time service level/service path adjustment implemented by Bridge & Roll facilitates network planning; and real-time service level/service path adjustment implemented by Bridge & Roll facilitates network planning. /service path adjustment, convenient network planning; static network to dynamic network (service) online conversion, to avoid network upgrades/service upgrades brought about by network turbulence; the use of traffic engineering technology to avoid the lack of network-wide concept of the previous manual planning of the network, the network is prone to link resource constraints shortcomings, so that the entire network traffic balancing, to facilitate the future increase in service and expansion of the service to provide a differentiated level of service.

(3)OTN/" target="_blank" >WDM Feature Expansion

The OSN3500, OSN2500, and OSN1500 series can be extended with the addition of an optical add/drop multiplexing (OADM) board and a wavelength converter board to realize the OTN/" target="_blank" >WDM to solve the problem of insufficient fiber resources and large-grain data service transmission in some areas, and can provide chain or ring-type networking, and can also realize the protection of wavelength converter boards and the protection of the converter boards, the network security is very high.

3、Solutions

(1) OSN system function

OSN intelligent optical network system should provide transmission channels for voice services between facilities along Beijing-Shanghai Expressway and data, images and control signals of toll collection and monitoring system, and at the same time, it should also meet the requirements of network toll collection and the formation of a province-wide communication network, and network with the SDH transmission systems of neighboring road sections, such as Shihuang, Canghuang, Jinshang, and Baocang (2 under construction), etc., and make reservation for inter-provincial networking between Hebei Province and Tianjin and Shandong Province. It also reserves the access conditions for Hebei Province to realize inter-provincial networking with Tianjin, Shandong Province and other neighboring provinces and cities (i.e., providing STM-1 or STM-4 grade optical interface boards). It can be seen that the existing network should not only provide a transmission channel for charging, monitoring and information management, but more importantly, it should meet the requirements of future province-wide networking and even inter-provincial networking. Then the future network must have a high degree of intelligence, automation, broadband, SLA requirements. It is precisely OSN equipment can well meet such needs. For example: the flexible access of Mesh networking, coupled with topology auto-discovery, will make the expansion of the network simpler and safer; traffic control engineering, which can provide differentiated services for provincial centers, road centers, and road toll stations.

(2) OSN system networking

There are 1 communication center and 13 unmanned communication stations under Beijing-Shanghai Expressway. The communication network of this road section adopts SDH fiber-optic digital transmission system (composed of ADM equipment, REG optical repeater, network management equipment and single-mode optical fiber) and integrated service access network system (composed of OLT (optical line terminal), ONU (optical network unit), network management equipment and single-mode optical fiber) combined with the networking mode, and its network composition is shown in Figure 1.

Figure 1 OSN system network structure of Beijing-Shanghai Expressway

(3) OSN system configuration

Optix OSN3500/2500 ADM split-insert-multiplexing equipment

Based on the specific requirements of Hebei Province's networked toll collection and the implementation plan for the formation of the province's communication network, and combined with the actual demand for transmission channels for 2 Mbit/s services in this road section and adjacent nodes, this program sets up 1 set of Optix OSN 3500 optical network transmission equipment in Cangzhou Communication Center, configures the ADM according to the STM-4 level and establishes a 1+1 multiplexing segment protection chain.

At the same time, considering the service demand for networking with three areas (Qinhuangdao), one ADM node is set up in Qingxian mainline station, but because of the limited capacity of this node for sub-down/insertion service, one set of Optix OSN 2500 optical network transmission equipment is selected, and the redundant configuration of boards such as optical/electrical interfaces is reduced accordingly, so as to appropriately reduce the investment in the project.

In addition, in view of the possibility of realizing "inter-provincial networking" with Shandong Province in the near future, no ADM or REG equipment is configured in Wuqiao mainline station, but the optical channel has been implemented through.

Optix OSN1500 SDH transmission equipment.

When the integrated service access network system is implemented, the first thing to consider is the compatibility of equipment resources, such as whether the service board can be mixed and inserted, whether the network management software is compatible, etc., so as to ensure the "seamless" combination of the same series of products; the second thing to consider is the unity and coordination of the overall appearance of the equipment style, the Optix OSN1500 product was selected as the integrated service access network product. Optix OSN 1500 is selected as the built-in SDH transmission equipment for the integrated service access network system.

In general, OSN 3500/2500/1500 series products are based on intelligent optical network design, using high-capacity, generalized platform design, can realize the traditional network form to Mesh intelligent form of evolution, to achieve network intelligence and business intelligence, to provide multi-level, multi-service types of new services, and with the traditional SDH, MSTP network to maintain compatibility, integration of SDH, PDH, Ethernet, WDM, SDH/ " target="_blank">ATM, ESCON, FC/FICON, DVB-ASI, RPR and other technologies as a whole, to facilitate unified networking and centralized network management, so as to make the formation of the communication system more consistency, integrity and scalability.

(4) Network protection and self-healing

In the application practice of communication network, a prominent problem is how to realize network protection to ensure normal operation of the system. The method adopted in this scheme is to utilize pre-allocated redundant lines between network nodes to implement protection and form self-healing rings. In this way, when the future Mesh network is really established, according to the demand, automatically converted to gold level or other levels of service, and to achieve damage-free conversion.

For fiber-optic digital transmission system, 4-core fiber to form a 1+1 channel protection chain. As shown in Figure 2. During normal operation, the primary channel (W) of the 4 stations A, B, C, D work, the backup channel (P) is in hot standby, when the primary channel of a station is interrupted, it automatically switches to the backup channel to work, and then backs up after the primary channel is restored.

Figure 2 4-fiber 1+1 channel protection chain

The integrated service access network system adopts 2-core fiber to form a protection network by forming a ring across the station. As shown in Figure 3. During normal operation, the optical paths of stations A, B, C and D are A-C-B-D-A, and when the optical fibers of stations A and B are interrupted, the optical paths of station B and station A are B-D-A. Since the self-healing ring does not require human intervention, the communication function can be restored automatically in a very short time, so that human beings do not feel that the network has been faulty, and the service can be reversed without interruption.

Figure 3 2-fiber spacing station ring channel protection

(5) Network Management System

As the communication network has high availability, there is inevitable vulnerability, therefore, strengthening the management of each level of the network and equipment is also the main means to improve the quality of information transmission services and reduce maintenance costs.

This solution sets up a Huawei iManager T2000 network management system in the Cangzhou Communication Center to complete the network management of Optix OSN 3500/2500/1500 series transmission equipment in this section. At the same time, a Huawei iManager N2000 network management system is set up to complete the maintenance and management of HONET-FA16 equipment, power supply equipment and C&C08 program-controlled digital switches in the integrated service access network system, thus realizing the centralized management of "Three Networks in One" in the true sense of the word.