What is the use of VPC? There are two types of network services provided on the market: classic network and private network. VPC private network can help customers build a secure and isolated network environment on the public cloud. In the VPC network, customers can fully control their own exclusive network, including flexible customization of IP address range, configuration of routing tables and gateways, creation of subnets, etc., and create various cloud resources such as bare metal servers, databases, big data, etc. in the subnet to achieve secure and easy resource access and application access.
　　Private network (VPC) is a completely isolated network environment with flexible configuration to meet different application scenarios. You can host applications that provide services to the outside world in VPC, or you can perform access control isolation between application servers and databases, deploy web servers in subnets that can be accessed by the public network, and deploy the application database in a subnet that is not configured for public network access.
　　1. What are the specific uses of VPC?
　　1. Cross-regional high-speed interconnection: Cloud services are built entirely on VPC, helping users to achieve cross-VPC network interconnection services for office data synchronization, so that private network IPs can route traffic between peer VPCs, and achieve VPC network interconnection in the same region or across regions. Support VPC intranet interconnection, and VPC intranet interconnection in different regions and users can be achieved through high-speed channels. You can achieve cross-availability zone disaster recovery by deploying resources in switches in different availability zones.

　　2. Hybrid cloud environment deployment: logical isolation between different VPCs. If you have multiple business systems such as production environments and test environments that need to be strictly isolated, you can use multiple VPCs for business isolation. For example, by building a VPC private network hybrid cloud environment, the user's core data is deployed in the local data center under the cloud, and high-speed channel transmission is used to ensure fast synchronization of cloud data, so as to achieve data interconnection between the cloud and the cloud. You can also load dynamic IPs, configure firewalls and load balancing rules for any bare metal server.
　　3. Smooth migration: VPC provides a dedicated network connection, which can connect the local data center and VPC to expand the local network architecture. In this way, you can seamlessly migrate local applications to the cloud without changing the access method of the application. It supports the interconnection between the local data center and the VPC on the cloud, and the smooth migration of business to the cloud, realizing ultra-large-scale hybrid cloud deployment.
　　4. Second-level delivery: If your application bandwidth fluctuates greatly, you can configure DNAT forwarding rules through the NAT gateway, and then add EIP to the shared bandwidth to realize multi-IP shared bandwidth, fast and automated deployment, and complete the docking with a simple configuration of the  device in the user's data center, reducing the peak and trough effect, thereby reducing your costs.
　　The use of private network vpc
　　5. Multi-tenant security isolation: Through the VPC network, an isolated network with strict security access control is built. Users can deploy the core server or database system that processes core data and business in a subnet that is inaccessible to the public network, build an access control policy that fully meets industry standards, and meet the high-security isolation specifications of government affairs, finance, etc., so that the business is safe and worry-free.
　　6. Visual management: The network performance status is intuitively displayed in a graphical form, and the visual multi-dimensional monitoring alarm is convenient and efficient in the background management.
　　7. Public network access: SNAT configuration can be performed on the bare metal server in the VPC private network. Multiple bare metal servers can access the Internet through the same public network IP, and the public network IP can be replaced at any time to avoid being attacked by the outside world.
　　In the existing network environment, security is difficult to maintain, some business scenarios cannot be supported, and costs cannot be effectively controlled. Problems such as the emergence of VPC private networks have proposed a better solution to solve existing network problems. The advantages of security and smooth migration provided by VPC private networks are very important for the hot bare metal servers.
　　II. What other special features does the private network VPC have?
　　Routing table: VPC network can support management functions such/tunnel/DNS/port forwarding, as well as flexible scheduling, management, and control of traffic within VPC.
　　Hybrid cloud: Support VPC and multiple IDC environments to build tunnels to form a hybrid cloud environment that takes into account both public and private. Users can elastically expand bare metal servers and other resources of applications according to business volume, which not only reduces enterprise IT operation and maintenance costs, but also avoids the proliferation of enterprise core data.
　　Software-defined network: supports administrators to create and manage bare metal servers in VPC private networks, and flexibly manage network forwarding traffic of resources such as public networks and hybrid clouds in VPC by setting routing policies reasonably.
　　Load balancing: quickly improve service capabilities and enhance security; eliminate single points of failure; free DDoS attack defense function, dynamic startup without delay.
　　DNS configuration: through DNS configuration, bind domain names to resources in private networks, and each domain name can specify multiple private IPs at the same time.
　　NAT gateway: share public IP, support access to VPC external services, support high-speed bandwidth, high availability of dual-machine clusters, and easily break the Internet access performance bottleneck.
　　Elastic public IP: highly available elastic public IP address, which can be bound to a specified bare metal server on demand, or port mapping with a bare metal server.