While Internet Protocol (IP) has been a runaway success, today's IP networks are difficult to manage well. Operations costs are high and yet network reliability remains low. Our research begins from the observation that the root cause of these problems is IP's current management and control planes, which distribute vital state and control functions across multiple systems.
We take a clean-slate approach to network control, guided by the following three principles:
Network-level objectives: Running a robust data network depends on satisfying objectives for performance, reliability, and policy that can (and should) be expressed as goals for the entire network, separately from the low-level network elements.
Network-wide views: Timely, accurate, network-wide views of topology, traffic, and events are crucial for running a robust network.
Direct control: Decision logic should not be hardwired in protocols distributed among switches. Rather, the output of the decision logic should be communicated to switches explicitly.
The realization of these principles is the 4D Architecture, shown above. In it, we decompose the functions of network control into 4 planes: A decision plane that is responsible for creating a network configuration (e.g. computing FIBs for each router in the network); a dissemination plane that gathers information about network state (e.g. link up/down information) to the decision plane, and distributes decision plane output to routers; a discovery plane that enables devices to discover their directly connected neighbors; and a data plane for forwarding network traffic.
Franck Le, Geoffrey Xie, Dan Pei, Jia Wang, Hui Zhang. Shedding Light on the Glue Logic of the Internet Routing Architecture. Proceedings of ACM SIGCOMM '08, to appear.
Franck Le, Geoffrey Xie, Hui Zhang. Understanding Route Redistribution. Proceedings of IEEE International Conference on Network Protocols (ICNP '07), October 2007.
Franck Le, Geoffrey Xie. On Guidelines for Safe Route Redistributions. Proceedings of ACM SIGCOMM Workshop on Internet Network Management (INM '07), August 2007.
Hong Yan, David A. Maltz, T. S. Eugene Ng, Hemant Gogineni, Hui Zhang, Zheng Cai. Tesseract: A 4D Network Control Plane. Proceedings of USENIX Symposium on Networked Systems Design and Implementation (NSDI '07), April 2007.
Albert Greenberg, Gisli Hjalmtysson, David A. Maltz, Andy Myers, Jennifer Rexford, Geoffrey Xie, Hong Yan, Jibin Zhan, Hui Zhang. A Clean Slate 4D Approach to Network Control and Management. In ACM SIGCOMM Computer Communication Review. 35(5). October, 2005.
Jennifer Rexford, Albert Greenberg, Gisli Hjalmtysson, David A. Maltz, Andy Myers, Geoffrey Xie, Jibin Zhan, and Hui Zhang. Network-Wide Decision Making: Toward A Wafer-Thin Control Plane. Proceedings of HotNets III. November, 2004.
Albert Greenberg, Gisli Hjalmtysson, David A. Maltz, Andy Myers, Jennifer Rexford, Geoffrey Xie, Hong Yan, Jibin Zhan, Hui Zhang. Refactoring Network Control and Management: A Case for the 4D Architecture. CMU CS Technical Report CMU-CS-05-117, September 2005.
Geoffrey Xie, Jibin Zhan, Dave Maltz, Hui Zhang, Albert Greenberg, Gisli Hjalmtysson, Jennifer Rexford. On Static Reachability Analysis of IP Networks. Proceedings of IEEE Infocom '05. March, 2005.
D. Maltz, G. Xie, J. Zhan, H. Zhang, A. Greenberg, G. Hjalmtysson. Routing Design in Operational Networks:A Look from the Inside. Proceedings of ACM SIGCOMM '04. August, 2004.