Described are a system and method for use by a computing device to transmit information over a communication medium. The computing device communicates over the medium according to a protocol stack having a plurality of protocol layers. Information having an identifier is received at a first protocol layer from a higher protocol layer in the protocol stack. The computing device determines whether to present the information to the network communication medium based on at least one term of a contract associated with the identifier. Upon determining to present the information to the communication medium, the computing device incorporates the identifier in the information before placing the information on the network communication medium.