Page 267 - ITU-T Focus Group IMT-2020 Deliverables

ITU-T Focus Group IMT-2020 Deliverables 4

/book_store/home/<encrypted_account_identifier>, where the <encrypted_account_identifer> is a blob
that the book store server can understand and use to generate a custom home page. Names could also
indicate a type of calculation, for example /calc/4/2/times could return a content object with the value “8”.
In all these examples, we used ASCII names, but in practice name segments can be binary values not
necessarily human-readable.

3.1.1 Elements of ICN
An Information Centric Network is usually made up of content producers, content publishers, content
replicas, and content consumers. A producer generates a piece of content, such as a document, photo, movie,
or web page. It may have its own digital rights management (DRM) attached by the producer. A publisher
packages a piece of content for use in the network. This may include pre-encoding the content to certain
formats and names and signing them with a network identity. A replica distributes content from a publisher.
A consumer fetches content via network names from replicas. The download process at a consumer
understands the inherent security offered by the ICN, which usually allows authenticating every packet via
direct signature or implicit hash chain from the publisher. This is different than today’s security model, where
authenticity derives from a secure connection to a replica. In the simplest configuration, one entity is a
producer, a publisher, and a replica for its content.

Figure 10 – Typical ICN architecture

Figure 10 illustrates the typical ICN architecture, which we will make concrete by describing how an actual
instance of CCNx would handle these activities. In this example, a family videos an activity at home, such as
their baby. The video camera produces a structures MP4 byte stream. The publisher function – which may
reside on the camera, home gateway, or other device – segments the byte stream to CCNx Content Objects.
For a live stream like this, the publisher would segment it to a certain number of video frames in some
number of network packets (Content Objects). A CCNx Manifest tree incorporates those Content Objects by
hash in to a single signed manifest representing the whole video segment. The video segment is stored on a
first replica, such as a home gateway. The publisher updates the movie catalogue to include the new segment,
then repeats for the next segment. A consumer queries its nearest replica for the movie catalogue and
segments. If the nearest replica does not have it, the request is forwarded towards the publisher until
satisfied. The content travels to the consumer, optionally cached at intermediate replicas.

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