The evolving concept of Ephemeral State Processing (ESP) is overviewed. ESP allows development of new scalable end-to-end network user services. An evolving macro-level language is being developed to support ESP at the network node level. Three approaches for implementing ESP services at network routers can be considered. One approach is to use the existing processing capability within commercially available network routers. Another approach is to add a small scale existing ASIC based general-purpose processor to an existing network router. This thesis research concentrates on a third approach of developing a special-purpose programmable Ephemeral State Processor (ESPR) Instruction Set Architecture (ISA) and implementing microarchitecture for deployment within each ESP-capable node to implement ESP service within that node. A unique architectural characteristic of the ESPR is its scalable and temporal Ephemeral State Store (ESS) associative memory, required by the ESP service for storage/retrieval of bounded (short) lifetime ephemeral (tag, value) pairs of application data. The ESPR will be implemented to Programmable Logic Device (PLD) technology within a network node. This offers advantages of reconfigurability, in-field upgrade capability and supports the evolving growth of ESP services. Correct functional and performance operation of the presented ESPR microarchitecture is validated via Hardware Description Language (HDL) post-implementation (virtual prototype) simulation testing. Suggestions of future research related to improving the performance of the ESPR rnicroarchitecture and experimental deployment of ESP are discussed.

We present WASP (World-friendly Active packets for ephemeral State Processing), a novel active networks architecture that enables ephemeral storage of information on routers in order to ease distributed application synchronisation and co-operation. We aimed at a design compatible with modern routers hardware and with network operators' goals. Our solution has to scale with the number of interfaces of the device and to support throughput of several Gbps. Throughout this thesis we searched for the best trade-off between features (platform exibility) and guarantees (platform safety), with as little performance sacri ce as possible. We picked the Ephemeral State Processing (ESP) router, developed by K. Calvert's team at University of Kentucky, as a starting point and extended it with our own virtual processor (VPU) to offer higher exibility to the network programmer. The VPU is a minimalist bytecode interpreter that manipulates the content of the "ephemeral state store" of the router according to a microprogram present in packets. It ultimately allows the microprogram to drop or forward the packet on any router, acting as remotely programmable filters around unmodified IP routing cores. We developed two implementations of WASP: a "reference" module for the Linux kernel, and, based on that prototype experience, a WASP filter application for the IXP2400 network processor that proves feasibility of our platform at higher speed. We extensively tested those two implementations against their ESP counterpart in order to estimate the overhead of our approach. High speed tests on the IXP were also performed to ensure WASP's robustness, and were actually rich in lessons for future development on programmable network devices. The nature of WASP makes it a platform of choice to detect properties of the network along a given path. Thanks to per-flow variables (even if ephemeral) and its ability to sustain custom processing at wire-speed, we can for instance implement lightweight measurement of QoS parameters or enforce application-specific congestion control. We have however opted -- in the context of this thesis -- for a focus on another use of the platform: using the ephemeral state to advertise and detect members of distributed applications (e.g. grid computing or peer-to-peer systems) in a purely decentralised way. To evaluate the benefits of this approach, we propose a model of a peer-to-peer community where peers try and join former neighbours, and we show through simulations how efficiency and quality of user experience evolve with the presence of more WASP routers in the network.