Software Techniques for Multiservice IP Networks

The interest of the scientific and commercial telecommunications community for the use of software routers running in general purpose (PC) hardware, as an alternative to the traditional special purpose hardware routers, has grown quickly in the last few years. This is due to the high level of flexibility of this solution: the support for new protocols and network architectures and services, in fact, is easily obtained by re-programming the router itself. On the other end, the low cost of PCs and the continuous progress in their performance are making the design of a software packet switch, based on standard hardware platform, more and more attractive. In recent years, several proposals emerged, and a very promising architecture is the Click Modular Router, which is not only easily extensible, but also very effective: on a multiprocessor hardware, its maximum loss-free forwarding rate for IP routing reaches 1,250,000 64-byte packets per second. It allows the simple design and rapid implementation of new services: we first used it for the development of flow-based classifiers of real time traffic. Then, we introduced a traffic measurement mechanism and exploited several dynamical allocation schemes of the inter-domain link bandwidth, to maximize the bandwidth usage efficiency. Finally, we implemented a congestion and admission control technique, to preserve the bandwidth usage efficiency and avoid network congestion. These new functions were evaluated in terms of latency, jitter and bandwidth usage efficiency.