Implemented a rolling link latency history for switch links. Each link will...

Implemented a rolling link latency history for switch links. Each link will contain a single latency value. When a link update occurs, the latency computed from the LLDP packet is added to the exisiting link's LinkInfo. LinkInfo maintains a latency history for link L. The 1-to-1 mapping between Link and LinkInfo still exists. LinkInfo will provide a new latency based on the rolling window size and update threshold -- configurable through floodlightdefault.properties but default to 5 latency data points and 30%, respectively. As an example, the 0th latency value is used as the intial latency for a particular (new) link. Each LLDP update for this link will contain a latency. This latency is added to the LinkInfo from updates 0 - 3. Update 4 will make 5 historical latency data points. This will cause an average to be computed of these 5 data points. If the average is +/-30% of the latency recorded in the 0th latency, the link latency will be updated. For exach, successive latency recorded, the same average will be computed. If the new average is not +/-30% of the old recorded value, an update will not occcur. Every latency 'replacement/update' will cause a new topology to be computed in the topology manager. Keeping a rolling average takes into account current network conditions, but also helps to average out outliers and keeps topology updates to a minimum.