SAP J2EE Engine 6.20 Stand-alone version consists of a server and a dispatcher running in one Java Virtual Machine. It encapsulates all the functions of the SAP J2EE Engine 6.20 cluster. The difference between the two is that the Stand-alone Server cannot process as many requests as the cluster, which typically consists of a number of server and dispatcher nodes. Therefore, the response time to a large number of requests increases, and scalability is reduced. However, Stand-alone Server is a very good solution for a smaller number of requests, since it provides optimizations for better performance, and the communication between the server and dispatcher parts of the Stand-alone Server is not based on sockets.