Signaling in IP-Based Networks: Retrospect and Prospect

Protocols have been developed to provide various signaling services in IP-based networks - for example, for quality-of-service (QoS) reservations, or configuring middleboxes such as Network Address Translators (NATs) and firewalls. This article presents a retrospective view on the development of the IETF Next Steps in Signaling protocols, with a more flexible signaling framework than the traditional Resource ReSerVation Protocol (RSVP). The challenges are discussed for signaling in emerging network architectures like software-defined networking, network function virtualization, and service function chaining, as well as ongoing standardization efforts.