Hi, welcome back to the course! This section will introduce you to Alibaba Network Services Portfolios as a business unit of Alibaba group, Alibaba Cloud provides a comprehensive suite of global cloud computing services to power both their international customers online businesses and Alibaba Group's e-commerce ecosystem. Alibaba Cloud has been working hard for the slogan “more than just a cloud” by breaking down barriers of emerging technologies and redefining the digital world. Throughout Alibaba services, the whole development process of Alibaba service can be roughly divided into four stages. Stage one: migrate IT system on cloud. The initial products of Alibaba Cloud are to provide flexible and scalable cloud servers for enterprises through hybrid cloud with existing IT architecture. Thus, realizing the migration of IT systems in the cloud, the results of this phase meet the enterprise pursuit of cloud services. Many enterprises purchase servers and deploy non-core enterprise applications on Alibaba Cloud. The second stage: core business on global cloud. After the first step of service cloud, Alibaba Cloud strives to provide customers with more global cloud services. Nowadays, many regions have been deployed in China and even in the world, and then these IT resources have been utilized to realize the global public cloud and the global service strategic deployment of itself and its customers. At this stage, more companies are willing to deploy enterprise productivity or office applications on the cloud. The third stage: MicroServices on cloud. With more and more applications coming to the cloud, deploying cloud servers is cumbersome. Alibaba Cloud provides customers with better cloud MicroServices so that enterprises do not have to worry about complicated server operations and maintenance work, but focus on the purchase of MicroServices they need and improve the enterprise in the cloud office efficiency. The fourth state: Intelligent Cloud. With the advent of the era of big data, Alibaba Cloud is also embracing the challenge. Give full play to the advantages of many years of experience and provide customers with intelligent learning and large data service based on IoT so that they can promote visits through Big Data or AI. The continuous progress of cloud service is inseparable from the continuous development of network solutions. The development of Alibaba Cloud network solutions can also be roughly divided into three stages. Stage one: Internet access to cloud. The early solutions combined the virtual machine's network with the physical network to form a flat network architecture, such as the large layer two network. With the increase of virtual network scalability, problems are getting more serious for the early solutions. These problems include ARP’s proofing, broadcast storms, host scanning and more. Various network isolation technologies emerged to solve these problems by completely isolating the physical networks from the virtual networks. One technology isolates user with VLAN, but VLAN only supports up to 4,096 nodes. It cannot support the huge number of users in the cloud. The second stage: Private Hybrid Cloud. With the continuous development of cloud computing, virtual network requirements are getting higher and higher, such as scalability, security, reliability, privacy and higher requirements of connection performance. This gives a rise to a variety of network virtualization technologies. With the tunneling technology, Alibaba Cloud has developed V-Switch, Software-Defined Network (SDN) and Hardware Gateway, and thus created VPC. V-Switches are distributed the nodes. The gateway and the controller are deployed in clusters, and all links have redundant disaster recovery. This improves the overall availability of the VPC. The third stage: Global Cloud Network. In order to meet the needs of a global deployment, Alibaba Cloud provides CEN, GA and other services to provide users with a high-quality, efficient and stable network transmission environment. Cloud enterprise network CEN will provide a global network that can quickly build hybrid cloud and distribute business systems to help users build a cloud and network with enterprise skills and communication capabilities. Alibaba Cloud networking services provide you a highly stable, low latency and high-speed network with flexible hybrid cloud connections. Alibaba Cloud networking services deliver secure and reliable communication to and from RDCs in 19 regions globally. With more than 60 areas deployed globally, Alibaba Cloud’s large node network gives you access to close by nodes-shortening geographic distances. Alibaba Cloud has the following advantages in network service solutions – Cross-Region Global Network Connection. Alibaba Cloud provides fast and cost-effective networking services for multinational enterprises to build cross-region network connections. We ensure that your cross-region interconnections are legal and compliant. Fast deployment: Set up a multi-region networking environment in four easy steps and within five minutes. Cost effective: The cost depends on the demands of your network needs. No extra charges are required. Superior speed: It significantly reduces network latency, and it improves business processes and overall communication. China gateway: As a leading cloud provider in China, we provide reliable network connections at home and in China. For any industry, Alibaba Cloud hybrid cloud network solution enables you to connect your on-premise data from IDC, headquarters, branches, or offline stores to Alibaba Cloud. The hybrid network connections ensure that you are a cross-region interconnections are secure, reliable and flexible. Alibaba Cloud provides you with an easy-to-use interface to manage your networking services, such as Cloud Enterprise Network. You can set up a multi-region networking environment in four steps within five minutes. To sum up, selecting Alibaba Cloud service is to select the best quality and reliable service. Let's have a look at Alibaba Cloud network services portfolios. Alibaba Cloud network technology system is divided into three parts -- Cloud Network, Interconnected Cloud Network and Connect-to-Cloud Network. Cloud Network provides rich network functions on Alibaba Cloud and the management of access to public network traffic.