  Anycast routing is an IP solution that allows packets to be routed to the
topologically nearest server. Over the last years it has been commonly adopted
to manage some services running on top of UDP, e.g., public DNS resolvers,
multicast rendez-vous points, etc. However, recently the Internet have
witnessed the growth of new Anycast-enabled Content Delivery Networks (A-CDNs)
such as CloudFlare and EdgeCast, which provide their web services (i.e., TCP
traffic) entirely through anycast.
  To the best of our knowledge, little is known in the literature about the
nature and the dynamic of such traffic. For instance, since anycast depends on
the routing, the question is how stable are the paths toward the nearest
server. To bring some light on this question, in this work we provide a first
look at A-CDNs traffic by combining active and passive measurements. In
particular, building upon our previous work, we use active measurements to
identify and geolocate A-CDNs caches starting from a large set of IP addresses
related to the top-100k Alexa websites. We then look at the traffic of those
caches in the wild using a large passive dataset collected from a European ISP.
  We find that several A-CDN servers are encountered on a daily basis when
browsing the Internet. Routes to A-CDN servers are very stable, with few
changes that are observed on a monthly-basis (in contrast to more the dynamic
traffic policies of traditional CDNs). Overall, A-CDNs are a reality worth
further investigations.
