bundle#

Pure OCaml implementation of the IETF Bundle Protocol Version 7 (RFC 9171) for Delay-Tolerant Networking (DTN).

Overview#

Bundle Protocol is a store-and-forward messaging protocol designed for networks with intermittent connectivity, long delays, and high error rates. It's the foundational protocol for Delay-Tolerant Networking (DTN), used in:

• Deep space communications (NASA missions)
• Disaster recovery networks
• Remote sensor networks
• Challenged terrestrial networks

A "bundle" is a self-contained message that can be stored at intermediate nodes and forwarded when connectivity becomes available.

Features#

• Full RFC 9171 Bundle Protocol v7 implementation
• CBOR encoding/decoding using the cbort library
• Support for all standard block types:
  • Payload block
  • Previous node block
  • Bundle age block
  • Hop count block
  • Extension blocks
• CRC-16 X.25 and CRC-32C integrity checking
• Endpoint ID support (dtn: and ipn: schemes)
• Streaming I/O with bytesrw

Installation#

opam install bundle

Usage#

(* Create a bundle *)
let bundle =
  Bundle.v
    ~source:(Bundle.Ipn (1L, 1L))
    ~destination:(Bundle.Ipn (2L, 1L))
    ~creation_timestamp:{ Bundle.time = 0L; seq = 0L }
    ~payload:"Hello, DTN!"
    ()

(* Encode to bytes *)
let encoded = Bundle.encode bundle

(* Decode from bytes *)
match Bundle.decode encoded with
| Ok decoded -> Printf.printf "Payload: %s\n" (Option.get (Bundle.payload decoded))
| Error e -> Printf.printf "Error: %a\n" Bundle.pp_error e

API#

Types#

• Bundle.t - A complete bundle
• Bundle.eid - Endpoint identifier (dtn:none, dtn:URI, ipn:node.service)
• Bundle.primary_block - Bundle primary block
• Bundle.canonical_block - Extension/payload blocks
• Bundle.timestamp - Creation timestamp

Functions#

• Bundle.v - Create a bundle
• Bundle.encode / Bundle.decode - Serialize/deserialize
• Bundle.payload - Extract payload data
• Bundle.previous_node / Bundle.bundle_age / Bundle.hop_count - Extract extension block data

Related Work#

• ION - NASA/JPL's production DTN implementation in C
• µD3TN - Lightweight C implementation for embedded systems
• DTN7 - Go/Rust implementations of BPv7

This implementation focuses on:

• Pure OCaml with minimal C dependencies
• Integration with the OCaml ecosystem (cbort, bytesrw)
• Type-safe API with comprehensive error handling

References#

• RFC 9171 - Bundle Protocol Version 7
• RFC 9172 - Bundle Protocol Security (BPSec)
• CCSDS 734.2-B-1 - CCSDS Bundle Protocol Specification

Licence#

ISC License. See LICENSE.md for details.