The key to the integration of PTN and TD maintenance under the FTTH trend

In the PTN network era, the integration of transmission and wireless maintenance must be put on the agenda. First, the core technology of the PTN network is packet switching. The "elastic pipe" feature enables the technology to have the advantages of statistical multiplexing, which greatly improves the resource utilization of the network. At the same time, it also brings about the problem of how to analyze network traffic and realize emergency communication guarantee without affecting the transmission network structure. Secondly, the technology deploys a powerful HQoS (Hierarchical Quality of Service, hierarchical QoS) function. Different types of services must be configured with different QoS attributes. How to reasonably formulate the QoS strategy of the service to achieve the service quality required by the wireless side will also become very urgent. In addition, compared with the SDH circuit, the reasons for the failure of the PTN transmission circuit, such as packet loss caused by network congestion, have become more complex and hidden. The above three points require that the transmission side must abandon the backward maintenance concepts and working methods of the traditional SDH network era, effectively strengthen communication with the wireless side, and timely understand the attributes of the wireless side services (including traffic, QoS and other characteristics), so as to give full play to the advantages of PTN technology.

　　Implement joint deployment on QoS policies

　　Quality of Service (QoS) refers to a network capability, that is, providing the required services for specific services on a network spanning multiple underlying network technologies (MP, FR, ATM, Ethernet, SDH, MPLS, etc.), and obtaining predictable service levels in terms of packet loss rate, delay, jitter, and bandwidth. PTN equipment has a powerful HQoS (hierarchical QoS) function, which can deploy 5 levels of QoS policies, including UNI, V-UNI, PW, Tunnel, and NNU, to achieve 7 different service levels, including CS7, CS6, EF, AF4, AF3, AF2, AF1, and BE, fully meeting the service level requirements of different types of services in all business scenarios.

　　

　　As China Mobile deepens its full-service strategy, the types of services provided by China Mobile will become increasingly diverse in the next few years. In addition to traditional voice services, home Internet services, group data services, videophone services, etc. will also become part of the company's revenue. Services with different service levels also have different requirements for transmission networks (such as bandwidth, latency, etc.).

　　In the past, the SDH/MSTP network was a "hard pipe". Regardless of whether it carried actual services, it would occupy the resources of the transmission network, and the utilization rate of network resources was not high. SDH/MSTP technology is a technology that meets specific needs in a specific era, and it is also outdated. PTN technology provides a "soft pipe". Its biggest advantage is that if the pipe does not carry actual services, it will not occupy transmission resources, which greatly enhances the flexibility of the network and maximizes the utilization rate of transmission resources. Therefore, for various wireless services with different service quality requirements, it is no longer reasonable to expect that all services can be transmitted with the same quality on the transmission network as in the past. The transmission side and the wireless side should reach a consensus on the QoS strategy (as shown in Table 1) to achieve more economical transmission of wireless services with different service quality requirements in the transmission network.

　　Realize synchronous switching of LAG protection between PTN and RNC

　　There is a problem of asynchronous switching of LAG (link aggregation group) protection between Huawei PTN3900 equipment and Huawei DRNC820 equipment. If the PTN equipment receives light at -35db, the equipment reports an ETH-LOS alarm (it may be anti-jittered, but it does not affect the switching), but the code streams sent by both parties are still normal. At this time, the switching has occurred on the PTN side, but the opposite RNC has no response and no switching has occurred. The asynchronous switching of LAG protection will cause all the sites carried by the RNC port to be out of service, which has a great impact. For the above faults, the transmission side and the wireless side need to strengthen communication and jointly develop solutions.