I read a paper that states that the protocol stack for web services includes network layer and then rest of the layers like XML messaging layer and Service Description etc are built on top of it. It further states that any number of protocols like HTTP, SMTP etc can be used for network layer. If we look at the standard protocol layering then these protocols HTTP/ SMTP etc belong to the application layer and not to network layer. The internet protocols are usually stacked in five layers Application- e.g. HTTP, SMTP etc Transport- e.g. TCP, UDP Network- e.g. IP Data Link Layer- e.g. Ethernet Physical At some other places in the paper they have used transport layer as to refer to the layer below XML messaging layer ? Am I missing something ?