STEM: seamless transport endpoint mobility

In the current TCP/IP inter-networking architecture, a transport layer connection or session is uniquely identified by the underlying 5-tuple information, viz. {Src IP, Src Port, Dest IP, Dest Port, Protocol}. This strong coupling between the session and the end-point attributes implies that any change to one or more of the elements in this 5-tuple invariably leads to session failure. We present an architecture (STEM) that decouples this strong association to enable seamless migration of active transport sessions across IP addresses and interfaces. We achieve this migration by directly communicating between the peers and dynamically updating the 5-tuple elements associated with the session. The migration is done in a transparent, simple and secure way.

Our architecture enables new and exciting applications such as fault-tolerant transport sessions (e.g. in BGP) and end-host mobility in the absence of mobile IP infrastructure. Although STEM can be used as an alternative to mobile IP, the two may co-exist as well, if desired. The novelty of this architecture is that it does not require any modifications to standard protocols or applications. In other words, no changes are needed to the finite state machine or protocol messages. We present an implementation of the STEM architecture and validate it by means of experimental results.