One of the tasks of an enterprise architect is to desig...ramework atop which developers can implement and deploy applications consistently and easily. The consistency is important for internal business continuity and reuse; common objects, operations, and processes can be reused across applications to make development and integration with other applications and systems easier. Architects also often decide where functionality resides and design the base application infrastructure framework. Application server, identity management, messaging, and integration are all ofte...art of such architecture designs. Rarely does the architect concern him/herself with the network infrastructure, as that is the purview of that group; the you know who Im talking about group. And for the most part theres no need for architects to concern themselves with network-oriented architecture. Applications should not need to know on which VLAN they will be deployed or what their default gateway might be. But what architects might need to know and probably should know is whether the network infrastructure supports server offload of some application functions or not, and how that can benefit their enterprise architecture and the applications which will be deployed atop it. WHAT IT IS Server offload i...eneric term used by the networking industry to indicate some functionality designed to improve the performance or security of applications. We use the term offload because the functionality is offloaded from the server and moved to an application network infrastructure device instead. Server offload works because the application network infrastructure is almost always these days deployed in front of the web/application servers and is in fact acting a...roker (proxy) between the client and the server. Server offload is generally offered by load balancers and application delivery controllers. You can think of server offload lik...elay race. The application network infrastructure device runs the first leg and then hands off the baton (the request) to the server. When the server is finished, the application network infrastructure device gets to run another leg, and then the race is done as the response is sent back to the client. There are basically two kinds of server offload functionality: Protocol processing offloadProtocol processing offload includes functions like SSL termination and TCP optimizations. Rather than enable SSL communication on the web/application server, it can be offloaded to an application network infrastructure device and shared across all applications requiring secured communications. Offloading SSL to an application network infrastructure device improves application performance because the device is generally optimized to handle the complex calculations involved in encryption and decryption of secured data and web/application servers are not... TCP optimization i...ittle different. We say TCP session management is offloaded to the server but thats really not what happens as obviously TCP connections are still opened, closed, and managed on the server as well. Offloading TCP session management means that the application network infrastructure is managing the connections between itself and the server in suc...ay as to reduce the total number of connections needed without impacting the capacity of the application. This is more commonly referred to as TCP multiplexing and it offloads the overhead of TCP connection management from the web/application server to the application network infrastructure device by effectively giving up control over those connections. By allowing an application network infrastructure device to decide how many connections to maintain and which ones to use to communicate with the server, it can manage thousands of client-side connections using merely hundreds of server-side connections. Reducing the overhead associated with opening and closing TCP sockets on the web/application server improves application performance and actually increases the user capacity of servers. TCP offload is beneficial to all TCP-based applications, but is particularly beneficial for Web 2.0 applications making use of AJAX and other near real-time technologies that maintain one or more connections to the server for its functionality... Protocol processing offload does not require any modifications to the applications... Application-oriented offload Application-oriented offload includes the ability to implement shared services on an application network infrastructure device. This is often accomplished vi...etwork-side scripting capability, but some functionality has become so commonplace that it is now built into the core features available on application network infrastructure solutions... Application-oriented offload can include functions like cookie encryption/decryption, compression, caching, URI rewriting, HTTP redirection, DLP (Data Leak Prevention
