NLB-network load balancing

Network Load Balancing

What is Server Load balancer? A server Load balancer consists of multiple servers in a symmetric manner. It has an equivalent position, and can provide external services independently without the assistance of other servers. Through Load Balancing Technology to evenly distribute external requests to a server in a symmetric structure The server that receives the request independently responds to the customer's request. The server Load balancer can evenly distribute customer requests to the server array, so as to quickly obtain important data, Solve a large number of concurrent access service problems. This cluster technology can be achieved close to large ones with minimal investment Host performance. Advantages of network load balancing First, network load balancing can spread incoming requests to up to 32 servers, that is, a maximum of 32 servers can be used to share external network request services. The Network Load Balancing Technology ensures that the server can respond quickly even when the load is heavy; Second, network load balancing only needs to provide one IP address (or domain name ); Third, when one or more servers in the network load balancing are unavailable, the service will not be interrupted. When the Network Server Load balancer automatically detects that the server is unavailable, it can quickly re-assign Client Communication to the remaining servers. This protection can help you provide uninterrupted services for key business programs, and increase the number of Server Load balancer instances based on the increase in network traffic; Fourth, network load balancing can be implemented on normal computers. Implementation process of network load balancing In Windows Server 2003, network load balancing applications include Internet Information Service (IIS) ISA Server 2000 firewall and proxy server, VPN virtual private network, Terminal Server, Windows Media Services (Windows VOD, video broadcast) and other services. At the same time, network load balancing helps improve the performance and scalability of servers to meet the increasing demand for Internet-based clients. Network Load Balancing allows clients to access the cluster with a logical Internet Name and virtual IP address (also known as the cluster IP address), while keeping the names of each computer. Next, we will introduce the implementation and application of network Load balancer on two general computers with Windows Server 2003 installed. Of the two computers, one is named A, the IP address is 192.168.0.7, and the other is named B, and the IP address is 192.168.0.8. Set the private virtual IP address of the Network Server Load balancer to 192.168.0.9. When the application is formal, the client only needs to use the IP address 192.168.0.9 to access the server. Network Service balancing automatically selects 192.168.0.7 or 192.168.0.8 to provide external services based on the load of each server. The specific implementation process is as follows: Only TCP/IP protocols can be installed on each computer that implements network load balancing. Do not install any other protocols (such as IPX or netbeui ), this can be viewed from "Network Connection Properties. Step 1: log on to server a and server B as administrators and open the local connection interface of the two machines, select the "Server Load balancer" option in "Use the following items for this connection" and enter the "properties" dialog box to set the IP addresses to 192.168.0.9 (that is, a dedicated IP address for Server Load balancer ), set the subnet mask to 255.255.255.0; Step 2: Go to the "Internet Protocol (TCP/IP)" attribute settings page of server a and server B, and click "advanced, in the displayed "Advanced TCP/IP Settings" interface, set the IP address 192.168.0.9 and subnet mask to 255.255.255.0. Step 3: exit the "Local Connection Properties" Window of the two computers and wait patiently for the system to complete the settings. In the future, if the two servers cannot meet the requirements, you can add the third and fourth computers to the Network Load Balancing System in the above steps to meet the requirements. Use IIS to verify network load balancing After the network load balancing is configured, in order to implement a specific service, you need to install the corresponding service on the network load balancing computer. For example, to achieve Load Balancing for IIS websites, you need to install the IIS service on the corresponding network load balancing server. To allow each user to access consistent data when accessing different computers through network load balancing, data consistency must be maintained on each computer of network load balancing. For example, the network load balancing of IIS on two nodes is realized. To ensure the consistency of the content of the two websites, in addition to the same configuration of the two IIS servers, the corresponding website data must be consistent. To verify the network load balancing, we can use IIS for verification. Other applications, such as terminal services, Windows Media Services, and IIS applications, are similar. In the IE browser of another computer, type 192.168.0.9. According to the network load, the network load balancing will automatically forward to machine A or machine B. To verify the effect, you can unplug the network cable of the first computer or the network cable of the second computer during browsing. Different contents may be displayed. Of course, during the test, in order to verify the effect of network load balancing, we set the two websites as inconsistent content, while in the formal application, the content of each node and computer in the network load balancing cluster will be consistent, so that no matter which node is used for response, the accessed content will be consistent. Application of Server Load balancer in Campus Network In addition to teaching, scientific research, management, and retrieval of books and information, the campus network is also used for internal and external information exchanges, email, announcements, and news releases, and access to various public network ports. As the information transmitted over the network is not only numbers, text, and graphics, it will gradually increase applications with high bandwidth as the application level increases. Therefore, the construction of the network, especially the backbone network, requires high bandwidth and high speed. Applying the Server Load balancer technology to campus network servers is a cheap solution.