The development of OTN can be divided into three aspects: long distance, metro and OTN interfaces.
1. OTN in long-distance network applications
In long-distance networks, OTN equipment focuses on cross-capacity, and OTN has the ability to have large crossovers to build an end-to-end OTN crossover network. Among them, the provincial 40GWDM system may require a 10Tb/s cross rate; the provincial long-distance network can be integrated with the WDM system.
2. OTN application in metropolitan area network
In the metropolitan area network, there are mainly three usage scenarios.
Build a brand new OTN network to carry IP services, including between core routers and between BRAS and core routers;
Integrated with WDM systems, OTN devices can provide county-to-city connections;
OTN devices focus on business mapping aggregation and reorganization.
3. Application of OTN interface
OTN interfaces will become more and more common, including the progress of P-OTN; routers may use channelizeOTN to connect to the transport network.
China Telecom OTN test progressChina Telecom has organized several rounds of OTN testing. Currently, OTN equipment of various manufacturers is basically mature, and it has the ability to be tested and evolved in the trunk line. The test progress is as follows:
Currently, ODU1, ODU2, STM-16, STM-64, and 10GELAN (GFP-F) service interworking and protection interworking are implemented among vendors.
The STM-64 interconnect interface is used between the OTN device and the SDH device to verify the support capabilities of GE, STM-16 and STM-64 services, and end-to-end protection and segmentation protection.
First, the electrical layer cross capacity and granularity: 2.56 TOTN overhead capacity and networking capability: the overhead processing is perfect and the interoperability is good;
Second, the OTN branch line separation and protection capabilities: rich protection type, good interoperability;
Third, the OTN-based ASON application capability: the control plane is basically mature;
Fourth, the interoperability of OTN and SDH: Huawei can support it.
OTN backbone network application scenario1. Provincial backbone network:
Combined with the construction of the backbone 40GWDM, the application of the WDM equipment based on the OTN cross-scheduling branch line is promoted to meet the requirements of independent evolution and development of the service network and the transport network, and the network construction cost is reduced;
The crossover capability of the existing OTN equipment is up to 2.56T, and it is still impossible to implement non-blocking full cross scheduling of all channels in one node. For the 80&TImes; 40GWDM system, in the extreme case of no landing service, two devices are still needed.
2. Provincial backbone network:
Firstly, the application of branch line separation WDM equipment based on OTN cross scheduling in the provincial bone network is promoted.
Establish a backbone OTN network in the province when the cross-capacity of the equipment meets the application requirements.
At present, the 2.56T crossover capacity is suitable for applications in a 10GWDM system-based network, and can terminate 10GWDM systems in several directions.
OTN equipment improvement direction and goalsIt is recommended that the manufacturer be provided with the correct configuration template for OTN overhead and alarm handling so that maintenance personnel can complete the configuration work more easily. Standardize the mapping and encapsulation of GE services and verify their interoperability. It also promotes the vendor's support for the GFPCMFFDI/RDI delivery mechanism defined by ITU-T G.7041/Y.1303 (10/2008) to prevent single-pass state when unidirectional transmission failure occurs in GFP-F non-transparent encapsulation. At the same time, the normative content of the protection switching conditions is revised and clarified to avoid misunderstanding. Finally, in order to meet the application requirements of large dispatch nodes in the provincial backbone network, the crossover capacity needs to be further improved.
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