Abstract ASON technology is the development of optical transport network a major breakthrough, the paper discusses the advantages of ASON networks as well as the relationship between SDH and OTN, ASON is discussed in detail the transmission plane, control plane, and network management features and progress of the plane, and finally for the optical transport network evolution strategy to the ASON may be analyzed.

  Keywords automatic switched optical network user network interface synchronous digital sequence quality of service

2000 years later, the optical transport network technologies there are new developments, mainly automatic switched optical network (AutomaticallySwitched OpticalNetwork, ASON) the emergence of its most prominent feature is the introduction of an independent transmission network intelligence control plane, control plane to complete the routing using automatic discovery, call connection management, protection and restoration, so as to implement the dynamic call connection to the network management. ASON draws heavily on the exchange and data technology, to exchange, transfer and data in three areas has added a new intersection. Various manufacturers and operators of the technology have been given due attention. This will be the key technology and its progress ASON discussed in detail and based on current national transmission network operators, the characteristics of the technical evolution of the program may be discussed.

1 ASON technical characteristics 1.1 ASON advantages ASON is a service request initiated by the users, automatic routing, signaling control achieved by the connection establishment / removal, financial exchange and transfer as one of the next-generation optical network. Combined with the domestic transmission network operator status, ASON technology can solve the transmission network into three major technical challenges faced:

(1) the issue quickly to provide circuit

ASON most important feature is to quickly provide the circuit, using a distributed control can provide orders of magnitude in the second end of the circuit, the rate for 155Mbit / s, 2.5Gbit / s and so on. Businesses reduce the time help operators gain more customers and profit.

(2) transmission circuit QoS issues Transmission circuit current level of basic services can not be developed in accordance with the appropriate tariff policy, resulting in waste of resources, and ASON on the circuit can easily divide the priority to provide a service level agreement (SLA) of transmission circuits.

(3) can provide fast protection and restoration

Mostly rely on existing transmission network SDH rings to be protected, but the circuit efficiency is low, only 50%, while on the cross-ring circuit can not be effectively protected. The ASON can effectively solve the circuit protection and restoration can be completed in the second magnitude, and the cost of spare circuit less resources, general resources for the work of the circuit for 30% to 60%, well below the SDH ring network.

1.2 ASON and SDH, OTN relationship

Automatically switched optical network is divided into transmission plane, control plane and management plane in three parts. Transmission plane including the exchange of entities from the transmission network composed of network elements, is the realization of the connection establishment / removal, exchange and transfer of the physical plane. The introduction of ASON control plane is different from the traditional transport network is a fundamental point, which includes a series of real-time signaling and protocol system to realize the connection establishment, release control and monitoring, maintenance and other functions, the signaling control plane network support. Management plane is the control plane and transmission of the management plane.

ASON control plane is suited to the OTN (optical transport network), also applies to SDH, the transmission network as a unified control plane. SDH, OTN and ASON in the relationship can be expressed in Figure 1.

Can be seen from Figure 1, a separate SDH / OTN and does not constitute ASON, to constitute the ASON must SDH / OTN + plane + next-generation network management control plane (management and control can also plane and the transmission plane), three are indispensable. SDH, OTN transmission plane only ASON technology, ASON and SDH, OTN and does not contain relations.

2 ASON Technical Development 2.1 Technology transfer plane As the current line rate

reached 1.6Tbit / s, line capacity issue has been resolved. Transmission plane sent the most prominent problem is the node that the transmission network in the optical / electrical cross-machine, optical / electrical cross-machine is the core of transmission plane, the size of its processing capacity related to the ASON throughput and processing power, particle size .

Wavelength cross-current to achieve high capacity in three ways: The first is the all-optical switching, the second is the use of O / E / O (optical / electrical / optical) processing to achieve, the third is the photoelectric hybrid method. All-optical methods due to its stability and fault detection and location problems, is still in the experimental stage, commercialization will take some time. The opto-electronic hybrid approach the challenges facing the same way with all-optical. Now it seems the use of optical / electrical / optical approach is the mainstream product, especially in SDH-based optical / electrical / optical cross-machine (can be cross-VC-4 level). With the advent of large-capacity cross-chip (currently single cross-chip can reach 160Gbit / s and above), the core cross-cutting capacity of Tbit / s is not very difficult. To the market has been commercial-oriented 1.28Tbit / s products as an example, assume that input and output ports of the processing rate of 10Gbit / s, the cross-matrix of size 128 × 128 should be more than the capacity of its external service access 1.28Tbit / s. This rate of capacity is appropriate for the current network, although route on the backbone WDM System is 32 × 10Gbit / s, but the actual with the wavelength is usually 4 to 8, assuming that each line has eight wavelengths need to be processed, the matrix can be cross-direction of the end of the 16 WDM line. Even for such a core transmission node Beijing, currently meet the requirements. Using optical / electrical / optical mode is a characteristic of other low-level VC can cross to achieve a low rate of integration and aggregation, network more easily.

Optical / electrical / optical methods can support high-capacity cross-Machine VC-4 and VC-4-Xc level crossing. In the external interface is generally 2.5 Gbit / s, 10Gbit / s, can be G.707 SDH interface or G.709 OTN interfaces. SDH interface supports 2 fiber, 4 fiber MS-Spring multiplex section protection ring. As the connection status monitoring by the sending side must initiate the connection point and end point detection signal quality; for SDH, OTN, you can use SDH, OTN overhead for performance monitoring and fault management, such as SDH monitoring bytes B1, J0 , control surfaces need

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