The Carrier Pigeon Internet Protocol: An Algorithmic (and Lighthearted) Perspective

2026-05-10

AI Summary

This study addresses the problem of efficiently scheduling and breeding homing pigeons as a link-layer communication medium to meet given traffic demands while minimizing the number of pigeons required. Focusing on single-hop, two-hop, and multi-hop scenarios, the work introduces the first algorithmic framework for multi-hop pigeon-based communication, proves that the two-hop and higher variants are NP-hard, and develops a polynomial-time 2-approximation algorithm. By integrating demand aggregation strategies with combinatorial optimization and approximation techniques, the proposed approach guarantees fulfillment of all communication requirements while using at most twice the optimal number of pigeons, thereby significantly improving resource utilization efficiency.

Abstract

The theoretical model behind the pigeon post as a link layer in a communication network was introduced by Shannon (under the guise of studying One-Time Pads for cryptography). That is, to send a one-hop message to $v$, a node $u$ needs a mail pigeon bred and raised at $v$. When sending a message using a pigeon to $v$, node $u$ loses the pigeon. To send another message to $v$, node $u$ needs another pigeon of $v$. It has been demonstrated that the communication bandwidth achievable with pigeon post can exceed that of networks using other media. This has already motivated the introduction of Internet standards that allow the use of pigeons as Internet link-layer media. In this paper, we begin to fill in the missing piece: designing algorithms for breeding and scheduling pigeons to meet a given communication demand efficiently, minimizing the number of pigeons required. We consider singlehop, 2-hop, and multihop pigeon use. While the singlehop variant admits a simple characterization, both the 2-hop and the multihop variants are NP-hard. For the latter variants, we present a polynomial-time algorithm based on demand aggregation that achieves a 2-approximation for the number of pigeons used. We believe that this pigeon-based perspective offers both amusing and instructive insights into network design and hopefully, into ornithology.

Problem

• pigeon post
• communication demand
• NP-hard
• link layer
• network scheduling

Innovation

• pigeon post
• network scheduling
• approximation algorithm
• NP-hard
• link layer