A transport protocol is a network protocol that has the capability of transferring some payload from one node to another, thus providing some level of transparency from the underlying network.

Transport protocols are used as a mechanism to move payloads around a network. Typically, a payload will have a transport binding associated with it. For example, SOAP (acting as a payload) has a predetermined binding for HTTP (a transport protocol).

Some common transport protocols include: HTTP, HTTP-R, SMTP and BEEP.

It is not uncommon to find mechanisms that cross layers in the OSI stack, that is, they provide transport functionality but provide additional functionality as well (such as session, reliability, etc.) Included in this group are vehicles like JMS, MQ, instant messaging protocols, JXTA and others.