Minimum-Latency Transport Protocols with Modulo-N Incarnation Numbers

To provide reliable connection management, a transport protocol uses 3-way handshakes in which user incarnations are identified by bounded incarnation numbers from some modulo-$N$ space. Cacheing schemes have been proposed to reduce the 3-way handshake to a 2-way handshake, providing the minimum latency desired for transaction-oriented applications. In this paper, we define a class of cacheing protocols and determine the minimum $N$ and optimal cache residency time as a function of real-time constraints (e.g.\ message lifetime, incarnation creation rate, inactivity duration, etc.). The protocols use the client-server architecture and handle failures and recoveries. Both clients and servers generate incarnation numbers from a local counter (e.g.\ clock). These protocols assume a maximum duration for each incarnation; without this assumption, there is a very small probability ($\approx \frac{1}{N^2}$) of misinterpretation of incarnation numbers. This restriction can be overcome with some additional cacheing. (Also cross-referenced as UMIACS-TR-93-24.1

Comments on "Minimum-Latency Transport Protocols with Modulo-N Incarnation Numbers"

The authors comment on a class of minimum-latency transport protocols that have been analyzed by Shankar and Lee (see ibid., vol.3, no.3, p.255, 1995). The protocols use unique incarnation numbers and caching schemes to reduce the latency of connection setup whenever possible. They discuss three modifications to the protocol. (1) A modification to the opening procedure which eliminates some constraints for the correctness of the protocol. (2) A modification which allows data messages in the opening state of the client to be sent. This reduces the latency in some situations for the price of stricter constraints for correctness. (3) An alternate way of closing connections. Apart from these modifications, they also show that the proofs can be refined to get somewhat less restrictive constraints for the correctness of the protoco