Migratory TCP: connection migration for service continuity in the Internet

Abstract

Today's Internet services are commonly built over TCP, the standard Internet connection-oriented reliable transport protocol. The endpoint naming scheme of TCP, based on network layer (IP) addresses, creates an implicit binding between a service and the IP address of a server providing it, throughout the lifetime of a client connection. This makes a TCP client prone to all adverse conditions that may affect the server endpoint or the internetwork in between, after the connection is established: congestion or failure in the network, server overloaded, failed or under DoS attack. Studies that quantify the effects of network stability and route availability demonstrate that connectivity failures can significantly impact Internet services. As a result, although highly available servers can be deployed, sustaining continuous service remains a problem. We propose cooperative service model, in which a pool of similar servers, possibly geographically distributed across the Internet, cooperate in sustaining a service by migration of client connections within the pool. The control traffic between servers, needed to support migrated connections, can be carried either over the Internet or over a private network. From client's viewpoint, at any point during the lifetime of its service session, the remote endpoint of its connection may transparently migrate between servers.