We have seen two of the most widely used client/server-based application protocols: SMTP used to exchange electronic mail and HTTP used to walk the World Wide Web. We have seen how application-to-application communication is driving the creation of new protocol development frameworks such as SOAP and REST. And we have examined session control protocols, such as SIP and H.323, which are used to control multimedia applications such as Voice over IP. In addition to these application protocols, we looked at some critical supporting protocols: the DNS protocol used by the Domain Naming System and SNMP used to query remote nodes for the sake of network management. Finally, we looked at emerging applications—including overlay, peer-to-peer, and c....