Design and Implementation of a Native Socket Interface for the Bundle Protocol

As space communication architectures expand beyond low-Earth orbit, traditional Internet protocols—designed for low-latency, continuous connectivity—fail to meet the needs of these challenging environments. Delay-Tolerant Networking (DTN), and in particular the Bundle Protocol (BP), addresses these constraints through a store-and-forward model that tolerates long delays and disruptions. However, application-level adoption of BP remains limited due to its non-standard APIs, which diverge from the widely-used POSIX socket interface. This paper introduces a BP POSIX Socket abstraction that exposes BP communication as a native socket type via a new address family (AF_BP) within the Linux networking stack. The proposed architecture integrates BP sockets with existing system tools and kernel primitives while delegating protocol processing to a user-space daemon via Netlink. We validate the approach through the development of a Rust-based messaging application. Our results demonstrate that minimal code changes are required to adapt existing applications to DTN environments, and that user experience can be preserved—even improved—through delay-aware interface designs. The BP socket abstraction thus presents a practical and extensible path for broadening the operational reach of DTN technologies.