Controlling Strategy Retransmissions in Named Data Networking

Named Data Networking (NDN), an information-centric Internet architecture, contains a new architectural component named the strategy layer. This component introduces a new forwarding model, in which a forwarding strategy decides how to forward an Interest packet. In NDN, an application can pair its namespace to use a specific forwarding strategy in the local host, but has no control over the strategies used in remote routers. Despite the central role the forwarding strategy plays, its interaction with applications has not been explored or well understood. In this paper we study and decompose the core mechanisms of a forwarding strategy in NDN. We illustrate how the correctness of some NDN applications can be affected by the coupling between the application design and the strategy decision to retransmit an unsatisfied Interest. This coupling creates challenges for application developers, who must implement their fixed application logic on a variable forwarding mechanism, and can lead to failure of application correctness and performance. We propose a new retransmission abstraction that decouples this strategy mechanism from the application design, and differentiates application Interests from network retransmissions. This allows every application to determine its own retransmission policy. We show that in some use cases the proposed abstraction can maintain continuous traffic flow regardless of the strategy used.