Huawei OTN Optical Transmission Unit Network Application

OTN-based intelligent optical networks provide an ideal solution for large-granularity broadband transmission. The transmission network primarily consists of provincial backbone transmission networks, intra-provincial backbone transmission networks, and metropolitan area transmission networks (local). The metropolitan area transmission network (local) can be further divided into the core layer, aggregation layer, and access layer. Compared to SDH, OTN technology’s greatest advantage lies in its ability to provide large-granularity bandwidth scheduling and transmission. Therefore, the adoption of OTN technology at different network layers depends on the bandwidth scheduling granularity of the primary services. Based on current network conditions, the scheduling granularity of provincial backbone transmission networks, intra-provincial backbone transmission networks, and prefecture-level (local) core layer transmission networks is generally above Gb/s. Therefore, OTN technology, with its superior advantages and scalability, is prioritized for construction at these layers. For metropolitan area transmission networks (local) and access networks, OTN technology may also be a preferred option when the primary scheduling granularity reaches Gb/s.

1. National Trunk Optical Transmission Network

With the development of IP networks and services, the emergence of new services, and the rapid growth of broadband users, IP traffic has surged, and the demand for national trunk bandwidth has doubled annually. Wavelength division multiplexing (WDM) national trunk lines carry national backbone services such as PSTN long-distance services, NGN/2G/3G long-distance services, and the Internet. Due to the massive volume of traffic carried, WDM national trunk lines have a pressing need for service protection.

With the adoption of OTN technology, the IP over OTN transport mode for national trunk lines can implement various network protection features, including SNCP protection, SDH-like ring network protection, and mesh network protection. Its protection capabilities are comparable to SDH, while significantly reducing equipment complexity and cost.

2. Provincial/Regional Backbone Optical Transmission Network

Intra-provincial/regional backbone routers carry long-distance services (such as NGN/3G/IPTV/private lines for VIP customers). By building a provincial/regional backbone OTNS optical transmission network, secure and reliable transmission of large-granularity services such as GE/10GE, 2.5G/10GPOS, and more can be achieved. Ring, ring, and mesh networking are supported, and the network can be expanded on demand. Wavelength/sub-wavelength services can be scheduled and directed, providing wavelength/sub-wavelength dedicated line services for key customers. Other services, such as STM-64/1/4/16/SDH, ATM, FE, DVB, HDTV, and any other services, can also be transmitted.

3. Metropolitan/Local Optical Transport Network

At the core layer of the metropolitan area network, the OTN optical transport network enables large-granularity broadband transmission between metropolitan area aggregation routers, C4 network (central district/county) aggregation routers, and metropolitan area core routers. Router uplink interfaces are primarily GE/10GE, but may also be 2.5G/10G. In addition to enabling large-granularity transmission of telecom services such as 10GE/40G, 2.5G/10G, the metropolitan core layer OTN optical transport network can also access other broadband services, such as STM-64-0/1/4/16/SDH, ATM, FE, ESCON, FICON, FC, DVB, HDTV, and ANY. For Ethernet services, it can achieve Layer 2 convergence, improving Ethernet channel bandwidth utilization. It can also channelize wavelength/sub-wavelength services, enabling access to wavelength/sub-wavelength-specific services. It can also implement on-demand bandwidth allocation and optical virtual private networks, thereby achieving centralized bandwidth allocation. From a network perspective, it can also transform the complex network structure of the metropolitan area transmission network, clarifying the transmission network hierarchy.

4. Private Network Construction

With the increasing demand for enterprise network applications, large enterprises and government departments are increasingly demanding the operation of high-granularity circuits. However, private networks are significantly limited compared to carriers’ fiber network resources. The introduction of OTN increases circuit scheduling flexibility, not only increasing the number of high-granularity circuits but also saving significant fiber resources. At the metropolitan area network (MAN) access layer, ADSL2+/VDSL2 DSLAMs will be widely used for downlink broadband access equipment, with GE uplink being adopted. With the growing number of GE line users, the number of GE interfaces will increase significantly. ADSL2+ equipment is typically located 500 to 1000 meters from users, while VDSL2 equipment is ideally located within 500 meters. A large number of GE services need to be transferred to the BAS and SR at the central office. Using OTN, or a combination of OTN and OCDMA-PON, for transmission is a good option. This significantly reduces the rapidly depleted fiber resources directly from the fiber. OTN can also protect services and enhance the manageability of bandwidth resources and capacity at the MAN access layer.