forked from I2P_Developers/i2p.i2p
005ac38742
Part 1: Change bandwidth estimate to exponential moving average (Similar to Westwood+ Simple Bandwidth Estimator in streaming) instead of 40 ms bucket. Also use it for tunnel.participatingBandwidthOut stat. Remove linear moving average code previously used for stat Reduce RED threshold from 120% to 95% of limit Part 2: Fix the other part of RED which is the dropping calculation. Previously, it simply used the bandwidth to start dropping if it was higher than a threshold. The drop percentage rose from 0 to 100%, linearly, based on how far the bandwidth was above the threshold. This was far, far from the RED paper. Now, we follow the RED paper (see ref. in SyntheticREDQueue javadoc) to calculate an average queue size, using the exact same exponential moving average method used for bandwidth. Similar to CoDel, it also includes a count of how long the size is over the threshold, and increases the drop probability with the count. The unadjusted drop probability rises from 0 to 2% and then everything is dropped, as in the RED paper. The low and high thresholds are configured at 77 ms and 333 ms of queued data, respectively. The queue is "synthetic" in that there's not actually a queue. It only calculates how big the queue would be if it were a real queue and were being emptied at exactly the target rate. The actual queueing is done downstream in the transports and in UDP-Sender. The goals are, for an 80% default share, to do most of the part. traffic dropping here in RED, not downstream in UDP-Sender, while fully utilizing the configured share bandwidth. If the router goes into high message delay mode, that means we are not dropping enough in RED. Above 80% share this probably doesn't work as well. There may be more tuning required, in particular to achieve the goal of "protecting" the UDP-Sender queue and local client/router traffic by dropping more aggressively in RED. This patch also improves the overhead estimate for outbound part. tunnel traffic at the OBEP. Reviewed, tested, acked by zlatinb