The Breakdown of Network Functions into Manageable Network Elements

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The example edge routers for the fixed network give an interesting discussion around this issue.  The fixed network access is less standardised compared with the mobile networks due to the history and diversity of fixed networks. This makes broadband edge routers to extremely complex network elements with thousands of features and consequently to high margin boxes.

Therefore, the SDN approach of decomposing edge routers by separating the data and control plane have been studied and pushed into trial systems. Promising availability of many open-source functions is regarded as a prerequisite to these (low cost) concepts.

However, because of this decomposition the distributed system results in increased network  complexity. This is theoretically excellently shown through the CAP Theorem (Consistency, Availability and Partition tolerance) for the example of distributed databases. I.e. it will always need a compromise on at least one of the 3 extreme requirements for a distributed application.

The distribution of states, i.e. the fundamental difference between a connection of elements over a network vs. a fabric connection, together with the new open interfaces becoming visible on the network level; have so far stopped the full-scale market introduction. The integration effort on the network level simply will become complex and this effort will become the new high margin service!