You will often hear the term stochastic used in research papers on network architectures.
The Dictionary on my Mac defines it as:
> having a random probability distribution or pattern that may be analysed statistically but may not be predicted precisely.
> A stochastic process is one whose behavior is non-deterministic, in that a system’s subsequent state is determined both by the process’s predictable actions and by a random element.
In Networking Design the usage of “stochastic” refers to the load balancing mechanisms in a network hardware. The first time a given flow passes through a device, it will be allocated a given path. That path will continue to be used for all following packets/frames in the flow. For example, EtherChannel, LACP or other L2MP protocols.
The *random* nature is that you cannot predict the path of a flow in a multipath network and the path selection is, more or less, random. The action is *predictable* since load balancing will be repeatedly achieved across the available links in the bundle.
In networking, the “stochastic nature of load balancing” is that once a flow path is determined then this is the **only** path that can be used thus limiting the effective bandwidth to a single path.
And that can be problem for large flows that have repeatable characteristics. Thus, a SRC-DST MAC flow doesn’t change path once the first frame is switched. And the Forwarding Entry in the TCAM will have only one output interface for a given route even if it’s a equal cost path.