Is something along the below lines for the controller and management of SDN network and it open source implementation in the works...any pointers, feedbacks/guidance is much appreciated.
Thanks much.
Exploiting SDN Capabilities:
Some thoughts on the controller considerations for
exploiting programmable networks with information centric or content based
routing.
I was listening in to Stanfords Courseera course on PGM and Expander Graphs..and chanced upon Feynmans lectures where he was talking about the relationship to Mathematics and Physics where though Feynman hadnt mentioned explicitly seemed to touch upon convexity and duality.... ..and attempted to relate this to SDN networks....
Duality between the algorithmic approach and the nature of
the optimization problem.
One convex algorithmic approach
could be to resort to viewing the entire problem as a graph and optimize on the
nature of such graph.
One
non-convex algorithmic approach could be a
Newton gradient method.
Decomposition of an overall optimization problem into
non-convex subcomponents which subcomponents can be treated jointly as a convex
problem. Such decomposition method could
be by determining components (Exapander components?) that are well connected.
SDN:
Convexity could vary with the time window size of the
problem. At a given time instant or
narrow time window, (routing) the problem is a convex one which one or a narrow
set of optimum routing decisions, but due to changing traffic conditions, over
a period of time individual routing decisions become a non-convex optimization
problem. Therefore, an SDN control could possibly have non-convex (greedy?)
approach component and a non-greedy component (viewing problem as a graph with
expander subcomponets, each of which could in turn apply the greedy method).
When we bring time axis into the picture, the convexity of
the problem changes from convex (short time window) to non-convex (large time
window, to make decisions based on current and expected traffic pattern).
Therefore the algorithmic approach to the control could change from a non-convex (short time frame) to a convex (large
time frame). One way of doing this could
be for the non-convex components to contribute weights (which determination
could have a convex nature to it or at least partly determined by a convex
component) to the elements of the convex components (a graph)
When one considers the Information based routing capability,
ICN or advanced versions of the same. Here for a short time window, the
placement of Information is a non-convex problem, and based on typical
information demand, over a large time-window (placement and information content
of caches ) could be considered a convex one. Therefore, information superimposes an
orthogonal nature on the convexity to the data component of the SDN-ICN
combine.
Stochasticity and time window: While routing in any given
network necessarily has to be deterministic, the optimal nature of the same
introduces stochasticity amongst the possibly multiple options each of which
individually yield deterministic routing.
Here we would then need to consider the same issues as above
wherein a general problem could be started off with a PGM and based on expander
sections of this graph, now be decomposed into its non-convex (nature of the
probabilistic problem) subcomponents. It
appears that information placement and routing could draw heavily on such PGM
as semantic connectivity (again to be considered both across space and time as
the vanilla version described above) could be probabilistic. Bringing in
Content based Routing and Information Centric Routing therefore could be viewed
as bringing in a "placement"
component to routing problem, eerily close but probably a lot more complex than
what the VLSI folks deal with.
Therefore, the hardware folks probably have nothing to worry Software
Defined Networks are going to use Hardware algorithms after all
