Server load balancers or application delivery controllers typically balance load among a plurality of servers based on the one or more network protocol addresses, such as IP, TCP, network, transport or application layer addresses, of connection request packets. They may perform deep packet inspection into the packet payload to examine the payload content for a hint to optimize load balancing. Optimization based on deep packet inspection techniques include load balancing based on URL, domain names, application protocol types, and user information in the payload content. In these scenarios, server load balancers do not modify the request packets initiated from the host.
As Web traffic increases, number of servers a server load balancer serves also increases. Deep packet inspection techniques are also refined, particularly for Hypertext Transfer Protocol (HTTP) type Web sessions. A server load balancer may choose to insert a load balancer specific cookie to store a server load balancer's preference such that when the same host requests a service again, the load balancer can detect the special cookie and select an appropriate server. The special cookie is inserted when a server responds to a HTTP request from a host, and is detected when the host sends a subsequent HTTP request to a service via the server load balancer. When the subsequent HTTP request is received, the server load balancer removes the special cookie before sending the HTTP request to a server.
The processing of insertion, detection, and removal of the cookie is computationally consuming. Much of the computational requirement is in the detection of various HTTP header fields and sub-header fields where the special cookie is to be inserted, detected or removed. Thus, there exists a need for the processing of identifying various header fields and sub-header fields is assisted by a special hardware processing module, so as to reduce the computational requirement to handle the special cookie.