CWDM (Coarse Wavelength Division Multiplexing) system, namely sparse wavelength division multiplexing system, also known as coarse wavelength division multiplexing technology, as an economical and practical short-distance WDM transmission systems in MAN applications increasingly being recognized and has practical. Development of information technology, especially in high-growth represented INTERNET IP data services, resulting in the need for a transmission line bandwidth is growing. DWDM technology as one of the most effective methods of line bandwidth expansion in the long-distance backbone network has been widely used, has been basically meet the current demand. Network bandwidth bottlenecks gradually shifted to the MAN, MAN built into the current hotspot network construction. Coarse wavelength division multiplexing system (CWDM) with its unique advantages in the construction of the metro more attention.
Coarse wavelength division multiplexing system (CWDM) optical fiber can effectively save resources and networking costs, which solves the fiber shortage and multiservice transparent transmission of two issues, mainly used in metro aggregation and access layer, and can in a short time in the construction of the network and conduct business. CWDM low cost, low power, small size and many other advantages, currently has a large metropolitan transport applications. Combined with market demand, the development of applied G.652, G.653, G.655 fiber EXP λ series CWDM equipment to major operators and system integrators to provide a low-cost, high-performance transmission solutions, is the ideal choice for a growing metropolitan area networking.
CWDM system, flexible networking, can form point to point, star, chain, ring and other topologies, for operators to compete with larger regional attraction. CWDM market currently in the industry has been more and more applications.
1. The domestic institutions of higher learning old and new campus expansion application (point networking)
The figure is the case of a university CWDM system is applied, the old campus network center for the provincial network of nodes and resources; old and new campus distance 40km, hire local operators a pair of fibers. Customer requires on a pair of two-way fiber optic expansion of the six-way data services, each speed 2.5G.
Program simple explanation:
1. A typical point to point transmission scheme.
2.CWDM WDM equipment can do a full business: expansion of 8, that the use of a core optical fiber can carry four 8-wave two-way business, two-core fiber can carry 8-channel 16-wave two-way business.
3. Each path can reach a maximum speed 2.5G, backward compatible to 100M.
4.CWDM relay transmission equipment without the farthest reach 100km.
5. This program does not use the traditional single-fiber unidirectional transmission, the six-way business in two separate groups were Bidirectional transmission, if a fiber fails, another one will not affect the fiber business.
A video transmission network expansion application (star, chain-shaped networking)
1.Customer demand: 1.B, C, D, E, F, G each node requires two-way video and two-way video signals to a central node A convergence.
2. Each signal requires speeds of up to 2.5G.
3. provide duplex fiber between nodes. As shown below:
Pictured shows the star, chain-shaped networking
1.A point as the center of the engine room, and the room BDFG each node constitutes a star topology.
2. Due to AC, AE node has no direct optical fiber link, to be, respectively, after B, D are two routes to the A, to reduce the number of transmission cascade, ABC, ADE constitute chain-shaped topology, using OADM technology.
1. expresses its trunk single fiber, expresses a fiber business.
2. In this scenario, F, G, respectively, with only a two-core fiber, customers can stay out of a core as a backup or expansion.
3. The scheme of the B, C and points D, E, respectively, with a two-core optical fiber transmission, so that only in B, D OADM using two techniques, which can effectively reduce the number of layers due OADM cascade caused by trunk optical signal loss; in addition, for clients to stay out of a core fiber for backup or expansion.
4. all use single-way technology to isolate the business, if a fiber fails, another one will not affect the fiber business.
5. This program provides two bi-directional optical business in B, C, D, E, F, G points, all point to the A convergence.
3. a research institute of experimental network applications (ring networking)The experimental network has eight nodes, by a series into a core fiber ring network.
1. Provide a three-way light business each node.
2. Each business rate 2.5G.
3. require the use of a minimum number of CWDM wavelength transmission.
4. Provide node power-down service protection plan for future upgrades.
5. Provide fiber optic ring network protection program for future upgrades.
6. Project routing logic is as follows:
1. Look at the logic diagrams, each node distribution business, the routing logic is strong.
2. Because it is a ring network, this project required at each node using OADM technology.
3. The transmission route planning: Consider the shortest cross-point routing, can effectively reduce the transmission of light loss at the node;
4. Wavelength Assignment: between adjacent points using point to point mode, using two wavelengths, in the middle of the four cross-node routing, use the chain of transmission, because they do not intersect, you can use the public four wavelengths, so the total wave with a wavelength of 6 .
5. Node Power-down service protection plan: Each node in the passive input and output with a 2 × 2 non-locking type optical switch, protection principle is as follows:
With this protection scheme, if the transmission device is powered down, figure 1-2 switch is closed, cutting off the node from the network, the protection of the business being transferred, and the route is clear.
6. The fiber optic ring network protection schemes: a lower offer multi-core optical fiber ring network in client case, you can implement this program;
Out at both ends of each node access my company OPS-1-1 optical path protection switching device automatically when the main route fiber failure, can automatically monitor the identification, the transmission business as a whole switched to standby fiber, switching time of less than 15ms, completely affect the transmission business. Switching diagram is as follows:
According to the analysis, the formation of the program is as follows:
1. This program uses CWDM OADM and technology, multi-service transmission between eight nodes on a ring fiber.
2. This program logic is strong, each node can achieve three-channel two-way route, the rate per channel 2.5G.
3. The program in each node are used OADM technology, and optimized routing.
4. Each color wiring diagram represents a wavelength of physical connection, using a total of six wavelengths.
CWDM (OADM) also with RPR, SDH ring network, which not only can achieve double the capacity of the existing network, but also the use of self-healing RPR, SDH equipment, protection switching and scheduling of flexible features, so as to constitute a high-efficiency, high reliability and large-capacity information highway.