Guérin is an international leader in the field of computer networking, both for his major research contributions and his dedication to serving the community. He is widely recognized for his contributions to understanding the fundamentals of data network design and how networks can be designed to provide desired quality of service guarantees. His work was among the earliest in this area and is credited with laying the foundation for later work. He also made early contributions in wireless and cellular networks. His current research interests are in networked systems including aspects of network economics. He has published research in a variety of journals and served on advisory boards of international telecommunications companies. He is an ACM and IEEE Fellow and since 2013 has been a member of the the ACM Publications Board.