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The current operation of the DCI network(Part Two)

3 Configuration Management

During channel configuration, service configuration, optical layer logical link configuration, and link virtual topology map configuration are required. If a single channel may be configured with a protection path, the channel configuration at this time will be more complicated, and the ensuing Configuration management will also be more complicated. A dedicated service table is required just to manage channel direction, and business directions must be distinguished in the table, using solid and dashed lines. When the correspondence between OTN channels and IP links is managed, especially in the case of OTN protection, one IP link needs to correspond to multiple OTN channels. At this time, the management amount increases and the management is complicated, which also increases the management of excel tables. Requirements, to completely manage all elements of a business, up to 15. When an engineer wants to manage a certain link, he needs to find out the excel form, and then go to the manufacturer's NMS to find the corresponding, and then perform operation management. This requires the synchronization of information on both sides. Since the NMS platform of OTN and the excel made by the engineer are two man-made data, it is easy for the information to be out of sync. Any mistake will cause the business information to be inconsistent with the actual relationship. Correspondingly, it may affect the business when changing and adjusting. Therefore, the equipment data of the manufacturer is collected to a management platform through the northbound interface, and then the information of the IP link is matched on this platform, so that the information can be automatically adjusted according to the service changes of the existing network, and the centralized management of the information is ensured. and a single source of accuracy to ensure the accuracy of configuration management information.

When configuring OTN service provisioning, prepare the information description of each interface, and then collect OTN information through the northbound interface provided by the OTN NMS, and pair the relevant description with the port information collected by the IP device through the northbound interface. The platform-based management of OTN channels and IP links eliminates the need for manual information update.

For the use of the DCI transmission network, try to avoid the use of electrical cross-connect service configuration. This method is extremely complex in management logic, and it does not apply to the DCI network model. It can be avoided from the very beginning of DCI design.

4 Alarm management

Due to OTN's complex management overhead, signal monitoring during long-distance transmission, and multiplexing and nesting of different service particles, a fault may report dozens or hundreds of alarm messages. Although the manufacturer has classified alarms into four levels, and each alarm has a different name, it is still extremely complicated from the perspective of an engineer's operation and maintenance, and it requires experienced personnel to determine the cause of the failure in the first place. The fault sending function of traditional OTN equipment mainly uses SMS modem or email push, but the two functions are special for integration with the existing network alarm management platform of the Internet company's basic system, and the cost of separate development is high, so more needs to be done. The standard northbound interface collects alarm information, expands the functions while retaining the company's existing relevant platforms, and then pushes the alarm to the operation and maintenance engineer.

 

Therefore, for the operation and maintenance personnel, it is necessary to let the platform automatically converge the alarm information generated by the OTN fault, and then receive the information. Therefore, first set the alarm classification on the OTN NMS, and then perform the sending and screening work on the last alarm information management platform. The general OTN alarm method is that the NMS will set and push all the first and second types of alarms to the alarm information management platform, and then the platform will analyze the alarm information of a single service interruption, the main The optical path interruption alarm information and (if any) protection switching alarm information are pushed to the operation and maintenance engineer. The above three information can probably be used for fault diagnosis and processing. When setting up reception, you can set up telephone notification settings for major alarms such as composite signal failures that occur only when optical fibers are broken, such as the following:

 

DCI network

Alarm Chinese description

Alarm English description Alarm type Severity and limitation
OMS Layer Payload Signal Loss OMS_LOS_P Communication Alarm Critical (FM)
Input/Output Combined Signal Loss MUT_LOS Communication Alarm Emergency (FM)
OTS Payload Loss of

Signal OTS_LOS_P Communication Alarm Critical (FM)
OTS Payload Loss Indication OTS_PMI Communication Alarm Urgent (FM)
The northbound interface of the NMS, such as the XML interface currently supported by Huawei and ZTE Alang, is also commonly used to push alarm information.

5 Performance Management

The stability of the OTN system is highly dependent on the performance data of various aspects of the system, such as the optical power management of the trunk fiber, the optical power management of each channel in the multiplexed signal, and the system OSNR margin management. These contents should be added to the monitoring project of the company's network system, so as to know the system performance at any time, and optimize the performance in time to ensure the stability of the network. In addition, long-term fiber performance and quality monitoring can also be used to discover changes in fiber routing, preventing some fiber suppliers from changing fiber routing without notification, resulting in blind spots in operation and maintenance, and the occurrence of fiber routing risk. Of course, this requires a large amount of data for model training, so that the discovery of routing changes can be more accurate.

6. DCN management

The DCN here refers to the management communication network of the OTN equipment, which is responsible for the network structure of the management of each network element of the OTN. The OTN network will also affect the scale and complexity of the DCN network. Generally, there are two methods of DCN network:

1. Confirm the active and standby gateway NEs in the entire OTN network. Other non-gateway NEs are ordinary NEs. The management signals of all ordinary NEs reach the active and standby gateway NEs through the OSC channel across the OTS layer in the OTN, and then Connect to the IP network where the NMS is located. This method can reduce the deployment of network elements on the IP network where the NMS is located, and use the OTN itself to solve the network management problem. However, if the trunk fiber is interrupted, the corresponding remote network elements will also be affected and will be out of management.

2. All the network elements of the OTN network are configured as gateway network elements, and each gateway network element communicates with the IP network where the NMS is located independently without going through the OSC channel. This ensures that the management communication of the network elements is not affected by the interruption of the main optical fiber, and the network elements can still be managed remotely, all of which are connected to the IP network, and the operation and maintenance costs for traditional IP network workers will also be reduced.

At the beginning of DCN network construction, network element planning and IP address allocation should be carried out. In particular, the network management server should be isolated from other networks as much as possible when deploying. Otherwise, there will be too many mesh links in the network later, and the network jitter will be normal during maintenance, and ordinary network elements will not be connected. Problems such as the gateway network element will appear, and the production network address and the address of the DCN network will be reused, which will affect the production network.


Post time: Dec-19-2022