On Aug 15, 2015, at 1:41 PM, Job Snijders <job@instituut.net> wrote:
On Sat, Aug 15, 2015 at 11:01:56PM +0530, Glen Kent wrote:
Is there a paper or a presentation that discusses the drops in the core?
If i were to break the total path into three legs -- the first, middle and the last, then are you saying that the probability of packet loss is perhaps 1/3 in each leg (because the packet passes through different IXes).
It is unlikely packets pass through an IXP more then once.
“Unlikely”? That’s putting it mildly. Unless someone is selling transit over an IX, I do not see how it can happen. And I would characterize transit over IXes far more pessimistically than “unlikely”. [Combining responses] On Aug 15, 2015, at 1:21 PM, Owen DeLong <owen@delong.com> wrote:
I would say that the probability of a packet drop at any particular peering point is less than the probability at one of the two edges.
However, given that most packets are likely to traverse multiple peering points between the two edges, the probability of a packet drop along the way at one of the several peering points overall is roughly equal to the probability of a drop at one of the two edges.
I’m a little confused why most packets are “likely to traverse multiple peering points”? Most packets these days are sourced from one of three companies. (Which Owen should know well. :) At least one of those companies published stats saying the vast majority of packets are “zero or one” AS hop from the destination. I cannot imagine Google or Netflix being 50% behind Akamai on that stat. Which clearly implies most packets traverse “zero or one” AS hop - i.e. one or zero peering points. Finally, I would love to see data backing up the statement that packets are more likely to drop at one edge (assuming the destination?) than at a peering point. -- TTFN, patrick