Server Load balancer technology Overview

Server Load balancer

SLB Load Balance is built on the existing network structure. It provides a cheap, effective, and transparent method, to expand the bandwidth of network devices and servers, increase throughput, enhance network data processing capabilities, and improve network flexibility and availability. Server Load balancer has two meanings: first, a large amount of concurrent access or data traffic is distributed to multiple node devices for separate processing, reducing the user's waiting for response time. Second, the operation of a single heavy load is distributed to multiple node devices for parallel processing. After each node device finishes processing, the results are summarized and returned to the user, which greatly improves the system processing capability.

Server Load balancer technical classification

Currently, many different load balancing technologies are used to meet different application needs, such as software/hardware load balancing, local/Global load balancing, higher network layer load balancing, and link aggregation technology. The software/Hardware load balancing software Load Balancing solution refers to installing one or more additional software on the operating system of one or more servers to achieve load balancing, such as DNS load balancing. It has the advantages of simple configuration, flexible use and low cost based on specific environments, and can meet general load balancing needs. The hardware Server Load balancer solution directly installs Server Load balancer devices between the server and external networks. Such devices are generally called server load balancers. Dedicated devices have completed specialized tasks and are independent of the operating system. The overall performance has been greatly improved. Combined with a variety of Load Balancing policies, intelligent traffic management can meet the best load balancing needs. In general, Hardware load balancing is superior to software in terms of functions and performance, but it is expensive.

Local/Global Load Balancing

Server Load balancer is divided into local Server Load balancer and global Server Load balancer based on the geographical structure of its applications. Local Load Balancing refers to load balancing for local Server clusters, and global Load Balancing refers to load balancing between server clusters with different network structures in different geographic locations. Local Server Load balancer can effectively solve the problem of excessive data traffic and heavy network load, and purchase servers with superior performance without expensive costs. It can make full use of existing equipment, avoid data traffic loss caused by server spof. With flexible and diverse balancing policies, data traffic can be reasonably allocated to servers in the server group to share the burden. To expand and upgrade existing servers, simply add a new server to the service group without changing the existing network structure or stopping existing services. Global load balancing is mainly used for websites with their own servers in multiple regions. In order to allow global users to access the server closest to their own server with only one IP address or domain name, in this way, the fastest access speed can be obtained. It can also be used by large companies with scattered sites in their subsidiaries to achieve unified and reasonable resource allocation through the internal Internet of Intranet enterprises.

Higher network layer Load Balancing

To address the different bottlenecks of heavy load on the network, we can start from different network levels and adopt the corresponding load balancing technology to solve the existing problems. Server Load balancer at a higher network layer usually operates on Layer 4 or Layer 7 of the network. Layer-4 Server Load balancer maps a valid IP Address registered on the Internet to multiple IP addresses of internal servers. It dynamically uses one of the internal IP addresses for each TCP connection request to achieve the purpose of Server Load balancer. Layer 7 Server Load balancer controls the content of application-layer services and provides a high-level access traffic control method, which is suitable for HTTP Server clusters. Layer-7 Server Load balancer performs Load Balancing tasks by checking the HTTP header and based on the information in the header.

Benefits of network load balancing

1. network load balancing allows you to spread incoming requests to up to 32 servers, that is, you can use up to 32 servers to share external network request services. Network Load Balancing Technology ensures that they can respond quickly even when the load is heavy.

2. Only one IP address or domain name must be provided for external network load balancing ).

3. If one or more servers in the network load balancing are unavailable, the service will not be interrupted. When the network load balancing automatically detects that the server is unavailable, it can quickly re-assign the Client Communication to the remaining servers. This protection can help you provide uninterrupted services for key business programs. You can increase the number of Server Load balancer instances based on the increase in network traffic.

4. network load balancing can be achieved on normal computers. 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 ServicesWindows on-demand video broadcast, and other services. At the same time, network load balancing helps improve the performance and scalability of your servers to meet the increasing demand for Internet-based clients. Network Load Balancing allows the client 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.