Software Defined Networks (SDN): Leveraging network state for rendezvous services

ion such as OpenFlow, but it can also mapped to existing mechanisms to configure and manage network elements. Clearly, the network and the applications that run on it are extremely synergistic. The applications can inform the network of desired behaviour (service-specific packet treatment, load at the application server) to have the network take proactive measurements (install new flow entries, instantiate new replicas). In the converse direction, the network can inform the applications of certain characteristics that will allow the application to behave more intelligently (network topology, routing costs, policies). In a broad sense, SDNs allow for this synergy to occur. SDNs have been envisaged as providing abstractions that "extract simplicity" from the network and reduce the need to "master complexity" when building applications that interact closely with the network [14]. SDN abstractions provide relevant information that applications can use to improve their functionality and provide the means for applications to specify desired network behavior without the need to be aware of network configuration details. The challenge is in developing the right abstractions that are useful for a large class of applications. Contribution: We posit that there is a class of applications, which we term as the rendezvous class, that can benefit from network introspection. Such applications are characterized by the simple requirement that a requesting application has a choice to pick one (or more) resources, and that these resources are available in the form of many replicas on the network.