Network-wide migrations of a running network, such as the replacement of a routing protocol or the modification of its configuration, can improve the scalability, manageability, security or the performances 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 work, we propose several techniques to address the problem of seamlessly (i.e. without loosing IP packets) modifying the configuration of commonly used routing-protocols.

In an interesting survey presented at MPLS 2010, Cariden, a vendor of provisioning and traffic engineering tools, describes the current deployments of MPLS. The survey mentions several interesting results :

• the three major MPLS vendors are Cisco, Juniper and Alcatel Lucent, more than 15% of the networks are multivendor
• 57% of the networks uses IS-IS, the others use OSPF