An apparatus and method are provided for handling protocol conversion. The apparatus has interconnect circuitry for routing messages between components coupled to the interconnect circuitry in a manner that conforms to a first communication protocol. Protocol conversion circuitry is coupled between the interconnect circuitry and an external communication path, for converting messages between the first communication protocol and a second communication protocol that has a layered architecture comprising multiple layers. The protocol conversion circuitry has a gateway component forming one of the components coupled to the interconnect circuitry, and a controller coupled with the gateway component and used to control connection with the external communication path. For a selected layer of the multiple layers, the protocol conversion circuitry provides, within the gateway component, upper selected layer circuitry to implement a first portion of functionality of the selected layer, where the first portion comprises at least protocol dependent functionality of the selected layer. It also provides, within the controller, lower selected layer circuitry to implement a remaining portion of the functionality of the selected layer, the remaining portion comprising only protocol independent functionality of the selected layer.