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Core network aspects 1

Figure 7-14 – Use case of proactive video caching with DAN

1) The end user sends a request to subscribe to a film to the service provider.
2) The service provider calculates the future locations of the end user, e.g., based on the train
timetable, and the network bandwidth at the locations (labelled 2-1 in Figure 7-14). Then, the
service provider pushes the segments of the film file to the relevant DAN nodes (2-2). Moreover,
the service provider provides the DAN elements with its public key that authorizes the DAN elements
to serve the corresponding segments of the film.
3) The end user accesses the DAN node and retrieves the segments of the film.

7.7.1 Benefits
The quality of video delivery to mobile users can be significantly improved by using the proactive video
caching mechanism supported by DAN. Since the video content being watched is pushed to the relevant DAN
elements in advance, it can be served immediately as soon as the mobile user changes the DAN element to
which it is attached. Thus, delay is minimized due to the reduction of the number of hops through which the
video content travels. Moreover, the cached video contents in the DAN elements can be accessed by all
subsequent mobile users.
Network operators can also benefit from this service scenario. First, the network bandwidth consumption
decreases due to the reuse of video contents in caches. Second, it is possible to reduce the level of energy
consumption of the network by accessing video contents through WLAN, which in general requires less
energy for transmitting data than cellular networks.
The benefits of proactive video caching have been shown in [b-Kanai, 2014]; see also Appendix III.

7.8 In-network data processing

This service scenario describes DAN as an in-network data-processing platform for an efficient IT system. This
service enables users to process data in a fast and flexible manner by distributing data-processing functions
and adaptively moving them over ubiquitous DAN elements, such as those on the edge of the network and
at concentrated points of data-processing requests. A similar concept that focuses on mobile edge
deployment has been proposed in [b-MEC, 2014]. On the other hand, this service scenario supported by DAN
can provide more flexible features, such as mobility, network-wide deployment and caching of data-
processing functions.

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