Download Multi-Stage Software Routers Implementation in Virtual Environment

Summary
Routers are the key components of modern packet networks and of the Internet in
particular. The request for high-performance switching and transmission equipment
keeps growing, due to the continuous increase in the diffusion of Information and
Communications Technologies (ICT) and new bandwidth-hungry applications and
services based on video and imaging. Routers have been able to support the performance growth by offering an ever increasing transmission and switching speed,
mostly thanks to the technological advances of microelectronics. But from another
point of view, nearly all of these high-end enterprise routers and core routers are
based on proprietary architectures which may influence the compatibility in the
total Internet frame work. Also the configuration of these routers and training
cost to manage multi-vender routers with different architecture is very high. These
shortcomings of encapsulation routers depress their growth but give researchers and
networking developers the possibility to find new ways to substitute or at least to cooperate with proprietary routers. One possible solution is based on software routers
exploiting personal PC architectures because of their low cost, open architecture
and continuous evolution due to Moore’s Law.
However, software routers suffer from intrinsic limitations of PC architectures:
CPU speed, bus and memory access speed may easily become a bottleneck. A
possible solution is to devise multistage software routers, i.e. architectures based on
PCs interconnection. This solution aims at building up a large scale size router, i.e.
a router with a large number of interfaces and huge routing capabilities. The thesis
focus on a previously proposed multistage architecture, based on the interconnection
of off-the-shelf PCs running open software such as Linux, Xorp, Click, Quagga.
Multiple PCs in the front-end stage act as interfaces and load balancers, whereas
multiple PCs in the back-end stage manage the routing functions. This multistage
architecture overcomes several disadvantages that single PC suffers to when acting
as routers, such as limited bus speed, Central Processing Unit (CPU) bandwidth,
limited scalability in terms of number of network interface and lack of resilience to
failures.
In recent years, virtualization techniques become reality, thanks to the quick
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