An apparatus comprising: network controller circuitry to be comprised in a first node, the first node to be communicatively coupled to a network and including a host processor to execute an operating system environment, the operating system environment including, at least in part, a communication protocol stack and an application, the circuitry to receive, at least in part, a packet from the network, the packet including, at least in part, a header and payload, the circuitry to issue at least one portion of the header to the stack, at least one portion of the payload being associated with the application, the circuitry to issue the at least one portion of the payload to a destination device in a manner that by-passes involvement of the stack, the destination device being specified, at least in part, by the application, characterised in that: the circuitry is to determine, at least in part, whether the packet is associated with a particular session, the particular session being comprised in a set of one or more predetermined sessions; based at least in part upon whether the packet is associated with the particular session, the circuitry is to issue the at least one portion of the payload to the destination device in the manner that by-passes the involvement of the stack. the circuitry also is to receive another packet that is associated with another session, the another session being comprised in another set of one or more respective sessions, the set of one or more predetermined sessions and the another set being mutually disjoint from each other; the another packet comprises another header and another payload; and the circuitry is to issue the another header, at least in part, and the another payload, at least in part, to the stack. network controller circuitry to be comprised in a first node, the first node to be communicatively coupled to a network and including a host processor to execute an operating system environment, the operating system environment including, at least in part, a communication protocol stack and an application, the circuitry to receive, at least in part, a packet from the network, the packet including, at least in part, a header and payload, the circuitry to issue at least one portion of the header to the stack, at least one portion of the payload being associated with the application, the circuitry to issue the at least one portion of the payload to a destination device in a manner that by-passes involvement of the stack, the destination device being specified, at least in part, by the application, characterised in that: the circuitry is to determine, at least in part, whether the packet is associated with a particular session, the particular session being comprised in a set of one or more predetermined sessions; based at least in part upon whether the packet is associated with the particular session, the circuitry is to issue the at least one portion of the payload to the destination device in the manner that by-passes the involvement of the stack. the circuitry also is to receive another packet that is associated with another session, the another session being comprised in another set of one or more respective sessions, the set of one or more predetermined sessions and the another set being mutually disjoint from each other; the another packet comprises another header and another payload; and the circuitry is to issue the another header, at least in part, and the another payload, at least in part, to the stack. the circuitry is to determine, at least in part, whether the packet is associated with a particular session, the particular session being comprised in a set of one or more predetermined sessions; based at least in part upon whether the packet is associated with the particular session, the circuitry is to issue the at least one portion of the payload to the destination device in the manner that by-passes the involvement of the stack. the circuitry also is to receive another packet that is associated with another session, the another session being comprised in another set of one or more respective sessions, the set of one or more predetermined sessions and the another set being mutually disjoint from each other; the another packet comprises another header and another payload; and the circuitry is to issue the another header, at least in part, and the another payload, at least in part, to the stack.