With the explosive growth of mobile communication services and broadband services, the traditional PTN and OTN network models are facing huge challenges. The new generation transmission technology - POTN (Packet-Optical-Transport-Network) has broad application prospects. This article introduces the shortcomings of PTN networks and OTN networks in the traditional local network mode, studies the necessity of the new generation transmission technology POTN, and discusses the application methods and application scenarios of this technology.

  New generation transmission technology POTN

   With the rapid growth of full-service access business volume, it has had a huge impact on the current mainstream transmission and bearer networks. The packetization evolution of optical transport networks is imperative, and POTN has emerged as a new generation of full-service transmission and bearer technology.

   In recent years, my country‘s three major operators and domestic and foreign manufacturers represented by Cisco, ZTE, Huawei, etc. have also initiated research on POTN, jointly discussed the application and development prospects of POTN in operators, and actively developed POTN products and solutions. , the POTN industry chain is gradually maturing, and large-scale commercial deployment is about to begin.

   1. Shortcomings of traditional networks and the necessity of POTN

In recent years, the independent networking modes of traditional PTN networks and OTN networks, which are mainly deployed in trunk lines and metropolitan area networks, have gradually exposed their shortcomings. First of all, PTN networks and OTN networks that focus on different network levels often have high construction and operation and maintenance costs due to different suppliers and different construction periods, and the difficulty of scheduling and management continues to increase. In addition, PTN networks lack the ability to carry large-granular services and large-scale services. Bandwidth, low cost, and long-distance transmission capabilities. OTN networks lack flexible bandwidth management capabilities and L3 VPN functions. Both have shortcomings in carrying services. Finally, the separate networking of PTN and OTN changes the structure and hierarchy of the transmission bearer network. It is complicated and takes up a lot of computer room space, power supply and pipeline resources, which is not conducive to the sustainable development of the transmission and bearer network.

The new generation transmission technology POTN is a platform for unified switching architecture, a platform for optical and packet integration, and a platform for unified carrying and unified management of all services. It can realize unified and flexible scheduling and interoperability at the optical layer and packet circuit layer. POTN is equipped with universal board slots, which can support a variety of service interfaces and line interfaces, and can flexibly configure OTN, SDH, packet data and other services according to needs. POTN can complete the functions of two or more planes, greatly simplifying the network level and complexity; POTN can also realize the access and long-distance transmission of large-granularity services such as 10GE, 40GE, and 100GE. In addition, POTN can save computer room space and reduce expenditures on computer room power supplies, pipeline resources, etc.

   2. Application methods and application scenarios of POTN

In the existing network, PTN and OTN networks are mainly used in the backbone aggregation layer. As the bandwidth demand gradually increases, there are the following two methods to apply the POTN network to the existing network:

1. Add DWDM interface to the existing network PTN equipment to realize long-distance and large-capacity service transmission;

2. Based on the PTN packet switching plane, add the ODUk switching plane to realize flexible service scheduling between packets and ODUk channels. Through the above method, the packet switching PTN network in the existing network can be smoothly upgraded to the POTN network. In addition, operators can also directly deploy POTN networks at the backbone aggregation layer.

POTN application scenarios can be divided into four major categories according to network level and business requirements.

Trunk line: In this scenario, POTN can complete the flexible scheduling and aggregation function of small and medium-sized granular services based on L2/L3 and the large-bandwidth, large-granularity, and long-distance transmission functions. In addition to meeting the needs of traditional trunk OTN and group business interface needs, it can also implement L3 VPN functions for LTE services.

Metro transport network: In this scenario, POTN can meet the flexible scheduling and aggregation of various small and medium-sized particle services, and has functions such as L3VPN and Ethernet. In addition, POTN can increase network-side bandwidth through technologies such as PIC, which can meet the bandwidth requirements of base station backhaul services.

Home broadband: PON networks have been widely deployed. Most OLT uplinks still use GE interfaces, but 10GE interface OLTs are becoming popular. POTN can be used to converge the OLT‘s upstream home broadband services and carry out large-bandwidth and low-cost transmission and scheduling of these services.

Group customers: For ordinary inbound services, MPLS-TP boards can be used to access the POTN network and transmitted through flexible pipes, which can meet the needs of flexible forwarding and flexible access of services. For high-value inbound services, CBR boards can be used to access the POTN network and transmitted through rigid pipes, ensuring large bandwidth, low latency, and high security.

   3. Conclusion

With the explosive growth in the number of LTE services and home-based customer services, the traditional network structure has been severely tested. A new generation of transmission technology, POTN, has emerged and has gradually been recognized and valued by peers. POTN can greatly simplify the network layer and network complexity, and can realize long-distance transmission of large-granularity services, and has very broad application prospects. POTN technology has obvious advantages over the independent networking modes of packet transmission network and OTN network in traditional transmission networks. It can be smoothly upgraded from the existing network to the POTN network. It has rich application scenarios and can meet various needs of the existing network.