Analysis of PTN knowledge in Access Network Technology

The Access Network Technology in China has developed very rapidly. It may be that many people do not know about the PTN in the access network technology. After reading this article, you will certainly have a lot of GAINS. I hope this article will teach you more. As the business needs drive the development of the network to AllIP, the technology of segmented transmission has become the mainstream IP bearer technology of the Next Generation transmission network. In the region where the man business needs are the most complex, the technology collision is the most intense, and new technologies are constantly emerging, the introduction of any advanced technology is not achieved overnight, especially in the face of a large and mature SDH/MSTP network, an ever-expanding IP Man, and the emerging full-service access network technology, the positioning of PTN in the network and its relationship with other networks need to be reconsidered. At the same time, as the PTN enters the commercialization stage, the specific networking strategy based on the PTN device has become the focus of attention of mobile operators.

1. Positioning of PTN in man

1) technical comparison
The SDH/MSTP network based on circuit switching ensures high-quality and secure transmission based on TDM services and supplemented by Ethernet data services through rigid allocation mechanism and single-board IP address, therefore, the bandwidth utilization is low. The kernel IP-based PTN technology has powerful bandwidth statistics reuse capabilities and is more active in the face of sudden and uncertain traffic impact, but compared with MSTP networks, the disadvantage of PTN lies in the access network technology of TDM services. PTN can also support TDM services through simulation, but its access capability is limited and can only be used as a supplementary means for TDM services, therefore, only IP-based services that meet high QoS requirements can truly reflect and take advantage of PTN.

Compared with traditional Ethernet, PTN inherits the end-to-end OAM management capabilities of traditional SDH/MSTP networks, and can provide differentiated services based on different QoS mechanisms, this is exactly what Traditional Ethernet does best. The main disadvantage of PTN is the cost. There is still a big gap between PTN and Traditional Ethernet in the short term.

Compared with the IPoverWDM/OTN technology, IPover WDM/OTN Technology focuses on solving the problem of ultra-long distance and ultra-high bandwidth transmission of IP services, it can provide point-to-point transmission channels for a large number of large particle businesses such as 2.5 Gbit/s, 10 Gbit/s, or even 40 Gbit/s, which is hard to achieve by PTN, however, IP over WDM/OTN bandwidth allocation is rigid and bandwidth utilization is not high. At the same time, the OTN device does not have a layer-2 convergence function. Therefore, the advantage of PTN lies in the flexible access of small particle IP services and convergence of services, it is not good at transmitting a large number of point-to-point large-particle businesses.

2) Network Layer
In the face of the need for a large number of IP-based services at the access layer of the Metropolitan Area Network, using SDH/MSTP or Traditional Ethernet cannot take both transmission efficiency and transmission quality into account, the IP-based kernel of the PTN device can effectively implement convergence and transmission of a large number of small particle businesses. It is very suitable for the features of large and sudden IP-based traffic at the convergence access layer of the Metropolitan Area Network. At the same time, the PTN inherits the powerful protection capabilities and rich OAM of transmission devices, providing carrier-level protection and monitoring management for businesses.

In the core backbone layer and trunk lines of the Metropolitan Area Network, point-to-point transmission of Large-size data services interconnected with various specialized network elements is the main cause. As such services do not require further convergence, therefore, the PTN technology is not suitable for applications above the backbone layer. Therefore, the introduction of the PTN technology will mainly rely on its advantages in business access flexibility, L2 convergence, and statistical reuse, focus on solving the access and transmission problems of the Convergence access layer, IPRAN, and all services of the Metro Transmission Network.

2. Relationship between PTN and other networks

The services that PTN can carry include base station services and leased line services with high QoS requirements, as well as high-bandwidth and burstable data services, this is closely related to and different from SDH/MSTP networks, IP Man networks, and full-service access networks that have been deployed or started in China Mobile Metro.

1) PTN and Metro MSTP Networks
After years of development, the structure of SDH/MSTP networks is mature and stable, and the network scale is also large, considering that SDH/MSTP also has considerable IP service carrying capacity, 2G services will continue to develop in the short term. Before the large-scale PTN deployment, traditional 2g small particles and sporadic small-scale leased lines can still be carried by SDH/MSTP networks to make full use of the previously configured network resources.

After the base station IP process is complete, a large number of base stations are carried by TDM instead of IP. In this case, there will be a large number of idle resources in the Metro MSTP network, considering the excellent service protection and OAM capabilities of the MSTP network and the extensive coverage capability formed after years of construction, the MSTP network can be effectively supplemented as a PTN, which makes the bandwidth demand less high, however, customers with high security and privacy requirements provide leased line access, and can cover areas temporarily inaccessible by PTN.

2) PTN and IP Man and full-service access network technology
PTN, IP Man, and all-service access network technology represented by PON technology. The three networks are unified and integrated under the second layer, but they are only oriented to different business objects. Firstly, the PTN adopts the layer-2 connection-oriented technology and integrates the statistical multiplexing and multicast functions of layer-2 devices. It can implement end-to-end carrier-level Ethernet service protection and bandwidth Planning Based on LSP, therefore, in terms of high-level service transmission and network fault locating, it has obvious advantages over the traditional layer-2 data network, and is especially suitable for carrying high-level base station businesses and large-account leased line businesses.

Due to the lack of QoS and network security of Users' Services, the IP metropolitan area network is mainly characterized by low cost and good scalability, use L2 switching devices to access the Internet and other low-level IP services with low real-time and reliability requirements.

The full-service access network technology focuses on intensive normal user access. According to different user needs, common solutions include PON + LAN, PON + PBX, and PON + switch, the full-service access network technology is used to connect and aggregate voice and data below the OLT. In the initial stage, when the business volume is small, the OLT upstream interface can enter the IP Man through the PTN or switch. during the full-service boom, IPoverWDM/OTN will surely sink further and carry the upstream business of the OLT.

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