As mentioned in the previous subsection, the forwarding module sends a copy of all request packets to the dispatcher once the connection has been handed off. Assignment of subsequent requests on the connection to back-end nodes other than the connection handling node is accomplished by tagging the request content. The dispatcher sends these requests reliably to the connection handling back-end using the control session between the handoff protocol modules. The handoff protocol at the back-end receives the requests, and places them directly into the Web server's socket buffer. The tags enable the Web server to fetch the target using back-end forwarding (see Section 7.4). It remains, however, unaware of the presence of the handoff protocol.
After the handoff, all packets from the client are sent by the forwarding module to the connection handling node where they undergo TCP processing. Thus, after the handoff, data packets from the client are acknowledged by the connection handling node. The contents of these request packets, once received, are however discarded by the connection handling node (see Figure 10). Instead, the tagged requests received from the front-end via the control connection are delivered to the server process.
