The growing energy consumption of Information and Communication Technology (ICT) has raised concerns about its environmental impact. However, the carbon efficiency of data transmission over the Internet has so far received little attention. This carbon efficiency can be enhanced effectively by sending traffic over carbon-efficient inter-domain paths. However, challenges in estimating and disseminating carbon intensity of inter-domain paths have prevented carbon-aware path selection from becoming a reality. In this paper, we take advantage of path-aware network architectures to overcome these challenges. In particular, we design CIRo, a system for forecasting the carbon intensity of inter-domain paths and disseminating them across the Internet. We implement a proof of concept for CIRo on the codebase of the SCION path-aware Internet architecture and test it on the SCIONLab global research testbed. Further, we demonstrate the potential of CIRo for reducing the carbon footprint of endpoints and end domains through large-scale simulations. We show that CIRo can reduce the carbon intensity of communications by at least 47% for half of the domain pairs and the carbon footprint of Internet usage by at least 50% for 87% of end domains.

翻译：信息和通信技术 (ICT) 的能源消耗日益增长，引起了对其环境影响的关注。然而，数据传输在碳效率方面的表现一直未受到足够的重视。通过在碳效率高的互域路径上传送数据可以有效地提高碳效率。然而，评估和传播互域路径的碳强度方面的挑战阻止了碳感知路径选择成为现实。在本文中，我们利用路径感知网络架构来克服这些挑战。特别地，我们设计了 CIRo，一个预测互域路径碳强度并在互联网上传播的系统。我们在 SCION 路径感知互联网架构的代码库上实现了 CIRo 的概念验证，并在 SCIONLab 全球研究测试床上进行了测试。此外，我们通过大规模模拟展示了 CIRo 减少端点和终端域碳足迹的潜力。我们展示了 CIRo 对于一半的域对来说，可以将通信的碳强度减少至少 47%，对于 87% 的终端域来说，可以将互联网使用的碳足迹减少至少 50%。