Server Load balancer

Server Load balancer (SLB) is a load balancing service that distributes traffic among multiple ECs instances. SLB can expand the external service capability of the application system through traffic distribution, and improve the availability of the application system by eliminating spof.

(In connection with CDN, CDN uses Server Load balancer. CDN uses the Global Server Load balancer technology to direct user access to a normal Streaming Media Server closest to the user, the Streaming Media Server directly responds to user requests. If there is no content to be accessed by the user in the server, the content will be automatically crawled from the original server and provided to the user according to the configuration. IPTV can use CDN to provide users with VOD services. After the video content is distributed to a CDN node near the user end through CDN, the end-to-end service quality can be guaranteed to a certain extent .)

CDN Load Balance [1] as the core components of the existing network increase with the increase of business volume, the traffic and data traffic increase rapidly, its processing capability and computing strength also increase accordingly, making it impossible for a single server device. In this case, if you discard the existing device to perform a large number of hardware upgrades, this will cause a waste of existing resources, and if you face the next increase in business volume, this will lead to a high cost investment for another hardware upgrade, and even devices with superior performance cannot meet the demand for increasing business volume. Load Balancing (also known as load balancing) is called load balance, which means to balance the load (work task) and distribute it to multiple operation units for execution, for example, the web server, FTP Server, Enterprise key application server, and other key task servers can work together to complete tasks. Server Load balancer is not a basic network device, but a performance optimization device. For network applications, Server Load balancer is not required in the first place. When the traffic of network applications increases and a single processing unit cannot meet the load requirements, the network application traffic will suffer a bottleneck, load Balancing will play a role. Server Load balancer has two meanings: first, a single heavy load operation is shared to multiple node devices for parallel processing. After each node device finishes processing, the results are summarized and returned to the user, the system processing capability has been greatly improved, which is often referred to as the cluster technology. The second layer means that a large amount of concurrent access or data traffic is distributed to multiple node devices for separate processing, reducing the user's waiting time for response, this mainly targets Web servers, FTP servers, key enterprise application servers, and other network applications. Generally, Server Load balancer is divided based on different layers of the network (layer-7 network. The second layer of Server Load balancer refers to the use of multiple physical links as a single aggregation Logical Link. This is the trunking technology, which is not an independent device, it is a common technology used by switches and other network devices. Modern Server Load balancer technology usually operates on Layer 4 or Layer 7 of the network. This is a server Load balancer Technology for network applications. It is completely isolated from switches and servers and becomes an independent technical device. This is also the object to be discussed. In recent years, layer-4 to layer-7 network load balancing has first been applied in telecommunications, mobile, banking, large websites and other units, because of its most prominent network traffic bottleneck. This is why each call goes through a Server Load balancer device. In addition, with the development of key network application services in many enterprises, the application requirements of Server Load balancer are also growing. More: http://zh.wikipedia.org/wiki/%E8%B4%9F%E8%BD%BD%E5%9D%87%E8%A1%A1_ (% E8 % AE % a1 % E7 % AE % 97% E6 % 9C % ba)

Server Load balancer