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.

翻译：香农（Shannon）曾以密码学中一次性密码本的研究为名，引入了将信鸽邮政作为通信网络中链路层的理论模型。即，节点u要向v发送单跳消息，需使用一只在v处养育的信鸽。当通过信鸽向v发送消息后，节点u会失去该信鸽。若要再次向v发送消息，节点u需要另一只属于v的信鸽。已有研究表明，利用信鸽邮政实现的通信带宽可能超过使用其他介质的网络。这促使了允许将信鸽作为互联网链路层介质的互联网标准制定。本文开始填补其中缺失的环节：设计用于信鸽繁殖和调度的算法，以高效满足给定的通信需求，并最小化所需信鸽数量。我们考虑了单跳、两跳及多跳信鸽使用场景。单跳变体具有简洁的表征形式，而两跳与多跳变体均属NP难问题。针对后者，我们提出一种基于需求聚合的多项式时间算法，可实现信鸽使用数量的2-近似。我们相信，这种基于信鸽的视角能为网络设计——甚至或许为鸟类学——提供既有趣又有启发性的见解。