China's IP routers are developing very rapidly, and their market applications are still many. So I studied the evolution of optical networks in IP routers to all-IP transport networks. The change in the type of service determines how the network evolves. In the business evolution, voice becomes an additional service, while the traditional telecommunication network is a network with voice service as the core, so the future network will be built around multiple services. Business IT and bearer IP routerization are the trend of network development, and should be considered comprehensively in the target network architecture. The industry's more all-IP routers are a general term, and more emphasis is placed on the widespread adoption of IP router formats for various service signals in the future, but this is not the same as the network is an end-to-end IP router network. It may be carried over Ethernet or transport network. An all-IP router cannot be understood as a replacement for all router networking. All-IP focuses more on the access layer and information format, that is, the service expressions that users feel, such as VoIP and IPTV. At present, the backbone network of the optical transport network is only providing end-to-end optical wavelength resources, and its core is IP/MPLS (multi-protocol label switching) network, but does not provide protection and recovery for IP. It is dedicated TDM (time division multiplexing). A comprehensive hosting platform for the business. The current status of the metropolitan area network is to provide integrated bearer tasks. Currently, it is a comprehensive bearer platform for non-DSLAM (Digital Line Subscriber Access) services. The main competitor is the new Ethernet technology. The transmission capacity of the transport network is increasing in the way of 10G to 40G and then to 100G and 100G+. The current 10G optical network is no longer able to meet the needs of service transmission. In 2006, 40G router applications have emerged, and the development of 40G optical networks has lagged behind the development of data services. Various broadband applications are the main driving force for the development of 40G transmission technology. On the one hand, the backbone bandwidth of the Internet has increased by 40%; on the other hand, the bandwidth capacity of services such as IPTV, triple play, and P2P is increasing according to Moore's Law, and relaying Bandwidth expansion. The 40GWDM system is the mainstream solution. At present, the main obstacles of 40G optical network are high system cost, complicated technology, high performance requirements of components, and high objective cost. The main reason is the commercial scale of products, because the procurement volume is small and the cost is low. It can't be lowered. At the end of 2007, mainstream manufacturers launched commercial solutions for 40G optical networks, 40 waves & TImes; 40G systems achieved a relay distance of approximately 1000 km, 80 waves & TImes; 40G systems achieved a maximum relay distance of 600 km - 800 km. Each vendor will provide an upgraded version at the end of 2008, supporting ULH (ultra-long-span DWDM technology) transmission, 40-wave & TImes; 40G system supporting ULH transmission over 1500 km, 80-wave & TImes; 40G system achieving ULH transmission over 1200 km. In areas where 40G business needs are concentrated, 40G optical networks will be built in batches. The newly built 10GWDM system should consider the possibility of upgrading to 40G, and design according to the 40G transmission index to support 10G/40G hybrid transmission. In the near future, 40-wave x 40G systems with 100 GHz spacing can be considered. In the next one to two years, 40-wave 50-GHz optical networks with 50 GHz spacing will become mainstream. The cost is mainly determined by the amount used, and the expected cost can be reduced to an acceptable level. OTN (Optical Transport Network) specifies a complex frame structure similar to SDH, with rich bytes for OAM (Information Field), similar to SDH, supporting mapping, multiplexing and cross-connection of sub-rate services, virtual cascade. OTN is more suitable for any customer service including SDH, Ethernet, video service adaptation, etc. It adopts asynchronous mapping and asynchronous multiplexing, and does not require system-wide synchronization. OTN is more suitable for building an end-to-end broadband service bearer network based on IP router services. The large number of data network service interfaces in the existing metropolitan area network are GE/10GE (G capacity Ethernet port). From the service and application level, GE will become a common interface interface similar to today's 155M. Since OTN processes large particles without the need to treat similar VC-4/12 fine particles, theoretically OTN can do more exchange capacity. The application of OTN in the metropolitan area network is not optimistic. People have an inert dependence on SDH. Except for the IP router service, the scheduling granularity in the metropolitan area network is mainly below 155M, and the SDH equipment can be satisfied. GE's processing is currently used for fiber-optic direct connection or WDM systems. The metropolitan area network Layer 2 network is a converged network and rarely needs to be scheduled within the metropolitan area network. GE services are mainly convergent and rarely cross-connected. At present, the networking between routers is directly connected by wavelength, and the transit node is not scheduled by the transmission device. The use of large-capacity crossover of OTN above 2.56 Tbps is a way to build a backbone network IP router network scheduling network. Initially, protection recovery and a small amount of redundancy can be avoided. After the technology of multi-layer recovery is improved or GMPLS technology is improved. Then carry out unified control and recovery. OTN is gradually maturing, and WDM devices with OTN interfaces have also been applied. It is worthy of attention whether the routers are going to OTN interface. In addition, whether an OTN network appears in the metropolitan area network needs to be observed, because the service type of the metropolitan area network is convergence, the scheduling amount is not large, and a large OTN network may appear on the backbone network. For OTN distributed control, Unified consideration. Semiconductor Plastic Package.Refers to the material whose conductivity is between the conductor and the insulator at room temperature. Semiconductors have a wide range of applications in radios, televisions, and temperature measurement. Diodes are semiconductor devices. 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