  Several major Internet service providers (e.g., Level-3, AT&T, Verizon) today
also offer content distribution services. The emergence of such "Network-CDNs"
(NCDNs) are driven by market forces that place more value on content services
than just carrying the bits. NCDNs are also necessitated by the need to reduce
the cost of carrying ever-increasing volumes of traffic across their backbones.
An NCDN has the flexibility to determine both where content is placed and how
traffic is routed within the network. However NCDNs today continue to treat
traffic engineering independently from content placement and request
redirection decisions. In this paper, we investigate the interplay between
content distribution strategies and traffic engineering and ask how an NCDN
should engineer traffic in a content-aware manner. Our experimental analysis,
based on traces from a large content distribution network and real ISP
topologies, shows that effective content placement can significantly simplify
traffic engineering and in most cases obviate the need to engineer NCDN traffic
all together! Further, we show that simple demand-oblivious schemes for routing
and placement such as InverseCap and LRU suffice as they achieve network costs
that are close to the best possible.
