<p>Elastic Load Balancing (ELB) is the unified and valid service entry of back-end service platform. It distributes access requests and data traffic to multiple back-end servers based on the predefined scheduling method and gets the response from those servers to realize load balancing and monitoring, application expansion, and high availability of application. ELB can satisfy user&#39;s demand for higher performance, higher expansion capability and the responding ability for massive user requests of system.</p> <p><strong><span style="font-size:18px">Overview</span></strong></p> <p>ELB publishes services externally through virtual IP addresses (VIPs). It can virtualize multiple back-end server instances into a high-performance, high-availability resource pool, and route requests from clients to hosts in the resource pool according to scheduling algorithms. By default, ELB checks the health status of the hosts in the resource pool and automatically removes abnormal hosts to improve the external service capabilities of back-end applications.</p> <p>In addition, ELB can also be used with security products of Ping An Cloud to enhance the protection capabilities of application services, such as free DDoS basic protection service.</p> <p><span style="font-size:18px"><strong>Types</strong></span></p> <p>Ping An Cloud provides the following types of ELB products:</p> <ul> <li><strong>External&nbsp;ELB</strong>&mdash;It is a novel ELB product which provides four-layer and seven-layer load balancing capability and is applicable to launch website or applications on the Internet.</li> <li><strong>Internal&nbsp;ELB</strong> (some regions)&mdash;It is a novel ELB product that provides four-layer load balancing capability and is applicable to load invocation request between internal systems in VPC.</li> <li><strong>Classic ELB </strong>(some regions)&mdash;It is traditional hardware ELB product which is applicable to traditional financial customers. Classic ELB can load the invocation request in VPC internal system and can also load the invocation request in East China region coordinated with Internet Gateway (IGW).</li> </ul>