Date Added: Jan 2011
Current data-centers employ admission control mechanism to maintain low response time and high throughput under overloaded scenarios. Existing mechanisms use internal (On the overloaded server) or external (On the frontend proxies) admission control approaches. The external admission control is preferred since it can be performed transparently without any modifications to the overloaded server and global decisions can be made based on the load information of all the back-end servers. However, external admission control mechanisms are bound to use TCP/IP communication protocol to get the load information from the back-end servers and rely on coarse-grained load monitoring due to the overheads associated with fine-grained load monitoring.