We implemented the VNF placement and scheduling solution
presented in this work in a proof–of–concept NFV management
and orchestration framework, named EmPOWER. Notice that,
the prototype currently supports only wireless access networks
based on the 802.11 family of standards and, as a consequence,
the applications described in the next section target Enterprise
WLANs and Campus networks scenarios. Nevertheless, as seen
in the previous sections, the provisioning model does not make
any assumption about the particular link–layer technology and
can be as well applied to any kind of radio access network
including OFDMA networks such as LTE and LTE–Advanced.
Our proof–of–concept is loosely modeled after the ETSI reference
NFV Architecture [9]. As it can be seen in Fig. 10, the
architecture is conceptually divided into three layers. The bottom
layer consists of the physical as well as the virtualized
resources composing the NFVI. In the second layer we have to realize complex VNFs. Finally, Click can be easily extended
with custom processing elements making it possible to support
features that are not provided by the standard elements.
Each WTP/CPP includes an OpenVSwitch instance, one or
more VNFs, and one Agent. The latter is in charge of monitoring
the status of each VNF as well as handling requests coming
from the controller. In the current implementation the monitoring
features include: number of packets/bytes transmitted and
received as well as the amount of resources (cpu time, memory,
storage) utilized by each VNF.
In the current prototype CPPs are built upon the Soekris
6501-70 platform consisting in single 1.6 GHz Intel Atom CPU,
2 Gbyte if SDRAM, and 12 Gigabit Ethernet Ports. CPPs
run Ubuntu 15.04 Server as operating system. WTPs exploit
the PCEngines ALIX (x86) embedded platform and run the
OpenWRT operating system.