In addition, content consumption has become increasingly personalized through the proliferation of video sites such as YouTube, BBC iPlayer and the like. As a consequence, such content is delivered via individual web-based connections to every end user, even in situations where many users are watching the same content at the same time.
The better alternative to this unicast approach is multicast. Multicast delivery is generally recognized as the most efficient delivery of the same content to many users at the same time, but today its application is limited to only live coverage of large-scale events.
How ICN helps
How does ICN help fix those issues? To shed light on this, let us outline a strawman ICN architecture that might make sense in a 5G vision. In this vision, ingress and egress points to the ICN network are clearly defined by backward-compatible gateway points that provide interworking between the legacy application/IP system and the ICN system. In the ICN publish-subscribe model, all that is required is that the network send packets along logically defined network paths.
These shortest path computations can be done via traditional mechanisms in each node. These paths are directly defined in the packet as a bit field of information. This bit field of information denotes every link in the network as a unique bit position, therefore defining a specific path as a unique bit field that combines all those bit positions of the links along the path. You might think this bit field would have to be enormous, but practically a field size of 256 is all that is really needed-assuming typical internet zoning principles are applied.
Forwarders merely need to check the presence of their output ports in the provided bit field of each packet. In this way, IP routing tables are wholly replaced by this in-packet bit field check, eliminating the need for expensive routing tables and limiting forwarding to a simple binary operation. ICN makes this efficiency improvement possible.
Of course, IP addresses as well as web names (URLs) still need to be mapped onto such path bit fields, but this mapping can now be performed in a virtual appliance that can be provided scalably in a data center at lower costs than in every router along the path. No such equivalent optimization is possible given how packets are routed in the traditional internet.
A virtual appliance approach also allows for load balancing, such as in the case of mobility where paths need to be recalculated for a direct path routing of the request, avoiding the triangular packet routing in IP. Protocol mappings in the ingress/egress points interpret HTTP requests/responses as a named data exchange. This ensures that HTTP requests are always routed to nearest replicas without the need for DNS-level redirections by announcing the availability of a new replica as a change of routing information with faster reaction times than observed for changes in today's DNS.
Sign up for CIO Asia eNewsletters.