Wire-Speed Hardware-Assisted Traffic Filtering with Mainstream Network Adapters - Advances in Network-Embedded Management and Applications - page 74

efforts for implementing monitoring applications are substantially reduced.
The framework is useful for implementing traffic analysis applications, such
as VoIP and IPTV monitoring software, where traffic filters must be
added/removed in real-time.
In our previous works, we decided not to leverage any specific monitoring
device in order to reduce costs and simplify the deployment. In this work
instead, we evaluate the opportunity of accelerating our framework by
exploiting mainstream NICs. Unlike special purpose monitoring hardware,
off-the-shelf network interfaces target the mainstream market and therefore
come at low end-customer prices. Even if these NICs are not designed for
accelerating monitoring software but rather tasks as virtualization, some of
their features can be successfully exploited for increasing the performance of
traffic analysis applications.
Modern off-the-shelf adapters provide several independent RX/TX queues
and hardware-based mechanisms such as Receive-Side-Scaling (RSS) that
balance network flows among RX queues mapped on processor cores. By
splitting the traffic among queues, the workload, both in terms of packet
processing and interrupts can be balanced across cores for better exploiting
the intrinsic parallelism of modern computing architectures. As of today, the
majority of server class adapters in the market are multi-queue enabled and
support RSS for splitting the traffic across queues. The main limitation of
RSS is that the balancing policy is static hence it cannot be adapted to
changing traffic conditions. This represents a serious limitation as workload
unbalances correspond to scalability penalties. Even if it is possible to
augment RSS with software based traffic balancing policies, this approach is,
in practice, unfeasible for high-speed networks as the performance penalty is
severe. Therefore, NIC manufacturers are introducing the second generation
traffic balancing hardware mechanisms that are dynamically configurable in
order to adapt traffic balancing policies to every traffic condition. Although
these mechanisms have been introduced for enhancing general purpose
networking, we believe that packet filtering will also benefit from these
breakthrough balancing technologies, and therefore, the performance gap
between special purpose monitoring devices and off-the-shelf network
adapters would be reduced.
In this work we present an advanced and yet easy to use open source software
framework that leverages the customizable hardware assisted traffic balancing
and filtering features introduced in modern NICs. As these filtering features
will likely be available in future NIC cards manufactured by various vendors
just as happened with RSS, we believe that this work is not limited only to the
specific NIC we considered in this paper, but it paves the way to supporting a
new family of cheap 10 Gbit (and 40 Gbit in the future) network adapters.