Seamless Network-Wide IGP Migrations

Authors: Laurent Vanbever, Stefano Vissicchio, Cristel Pelsser, Pierre Francois, and Olivier Bonaventure
Proceedings of the ACM SIGCOMM 2011 conference


Network-wide migrations of a running network, such as the replacement of a routing protocol or the modification of its configuration, can improve the performance, scalability, manageability, and security of the entire network. However, such migrations are an important source of concerns for network operators as the reconfiguration campaign can lead to long and service-affecting outages.

In this paper, we propose a methodology which addresses the problem of seamlessly modifying the configuration of commonly used link-state Interior Gateway Protocols (IGP). We illustrate the benefits of our methodology by considering several migration scenarios, including the addition or the removal of routing hierarchy in an existing IGP and the replacement of one IGP with another. We prove that a strict operational ordering can guarantee that the migration will not create IP transit service outages. Although finding a safe ordering is NP complete, we describe techniques which efficiently find such an ordering and evaluate them using both real-world and inferred ISP topologies. Finally, we describe the implementation of a provisioning system which automatically performs the migration by pushing the configurations on the routers in the appropriate order, while monitoring the entire migration process.



	title={Seamless network-wide IGP migrations},
	author={Vanbever, Laurent and Vissicchio, Stefano and Pelsser, Cristel and Francois, Pierre and Bonaventure, Olivier},
	booktitle={ACM SIGCOMM Computer Communication Review},

DOI: 10.1145/2018436.2018473