WDM metro and long-haul wavelength division due to the different needs of different applications and lead are also different in structure. Focus on ultra-long-haul WDM long-distance transmission and reduce the number of electrical relay, extensive use of all wavelengths OTM way down the back to back, despite the higher costs, but compared with the expensive electrical relay operators easily accept their prices. But the general distance within the local network will not be very long, between 200 ~ 400km, focusing node, rather than the line, the distance and transmission specifications reduce the number of small electrical relay, when the cost of business down the way it is is very important. If long-wave score back to back OTM clearly inappropriate way in the whole network, and therefore the introduction of metro WDM down OADM OADM (Optical Wavelength Add / Drop Multiplexer), make the desired wavelength selective channel without affecting the transmission of other wavelength channels. OADM avoid the traditional light - electricity - light conversion, directly in the optical domain of traditional SDH equipment electrical OADM function in the time domain; in addition OADM has a low insertion loss and improve the group network capacity. It can be said, OADM the wave subsystems from the initial point to point connections and develop into a multi-multipoint-to-multipoint connections, make DWDM system in the local network is more flexible and convenient, greatly reducing the metro WDM construction costs, and ultimately become the future optical network indispensable key components.
OADM applications in local network
Note the local gateway is how to reduce the cost of network construction and improve operational capability, so when OADM system in the local network, you should develop toward low-cost, high cost of direction as much as possible. On the basis of the original OADM based on the combination of the characteristics of the metro, and the introduction of tunable OTU C/DWDM integration and other features, greatly reducing network construction and maintenance costs, and further optimize the metro WDM.
Transmission network construction and operating costs is a major problem that must look into the current developments. Only both meet the development needs but also significantly reduce the cost of technology, will have a market and vitality. Metro WDM OADM design using a large capacity, multi-service, low-cost, scalable and management features, has become an important means of local network transmission solutions. Tunable OTU technologies emerge, bringing a new model GE business transfer, combined with C/DWDM integration and flexible design, greatly reducing the cost of network construction, bound with the development of data services widely available.
1. WDM equipment data transmission network solutions business
In the construction of the metro / local network, it is often at the core layer of the network selection is important to build OADM ring network backbone nodes. As the most senior of the core network, which is an integrated optical transport platform for voice, data and other services, plays a vital role in the transmission, dispatch, convergence and other aspects of the business.
Metro / local network data transfer has several OADM Figures 1 solution shown in Figure 2, the main features are as follows:
Figure 1 metro / local network data transfer solutions 1
Figure 2 Metro / local network data transmission solution 2
● Use ring network instead of optical fiber direct-drive, save a lot of valuable Metro / local fiber resources.
● System is flexible, scalable, supporting a variety of business rates and signal formats, providing transparent wavelength units of service scheduling, post-expansion of new business by simply increasing the wavelength without affecting the original operating wavelength, greatly enhanced the market competitiveness of the network.
● The number of wavelengths and down according to the actual needs of the early system planning, post-expansion easy to upgrade, the system bandwidth of up to 800G, the greatest degree of protection of the operator's construction investment.
● Network node scalability, and provide a variety of services, multi-rate interface, you can access to STM-1/4/16/64, FE, GE / 10GE, POS, ATM, FC, FICON, ESCON, DVB and 10M ~ 2.5G any rate business.
● For large particles service convergence convergence, such as 4 × STM-1/4 / 16,2 / 8 × GE, 8 × any summarization.
● For GE, 10GE and other important data services can provide a variety of protection on the optical layer, compared to conventional dual-homing protection, and efficient.
2. Metro / local network data transfer solutions
Between IP MAN core routing layer using OADM ring network (Figure 1), focused on solving network bandwidth bottlenecks and routing protection and other issues, the business mainly in GE, 10GE or POS business oriented. OADM not solve the core network data transmission, but also to carry voice traffic Metro / local transport network The following SDH ring. In addition, the metro / local network of large particles of business (such as 155M private line services, etc.) to provide convergence processing, efficient use of channel resources. For critical data services can provide two-fiber bidirectional channel shared protection on the optical layer, 1 + 1 optical channel protection technology.
3. Metro / local network data transfer solutions
In the metropolitan area or local network IP core routers, three switches using OADM network (Figure 2) between (different regions converged data services Switch), solve network bandwidth, long-distance transmission, fiber optic and other resource-constrained issues, business mainly in GE based. In the OADM ring network to transmit data traffic, you can put GE business planning usually dual-homed to single ownership, saving on expensive long-distance data port facilities, the business offers a variety of optical layer protection (ms level), the data than the traditional double attributable to protect more efficiently and quickly (seconds).
4. Metro / local network data transfer solutions
Between different regional or local network using IP MAN OADM network (Figure 3), to solve the problem of network bandwidth service protection, long-distance transmission, and GE single ownership. OADM ring network to build a large local network provides data transfer solutions. Because of equipment condition data network and cable resources, core routing switch data traffic may be attributable to a single GE connectivity, and can not form a ring. By OADM ring network group, can provide a variety of protection based on the optical layer for secure transfer of business to provide a reliable guarantee. In addition, OADM technology can solve the problem of long-distance transmission of data services across the prefectures and cities.