Drops in Core

Justin Wilson - MTIN lists at mtin.net
Mon Aug 17 14:51:34 UTC 2015


I could see it going through several private peering, but not through multiple exchanges.  


Justin Wilson
j2sw at mtin.net

---
http://www.mtin.net Owner/CEO
xISP Solutions- Consulting – Data Centers - Bandwidth

http://www.midwest-ix.com  COO/Chairman
Internet Exchange - Peering - Distributed Fabric




> On Aug 16, 2015, at 8:00 AM, Patrick W. Gilmore <patrick at ianai.net> wrote:
> 
> On Aug 15, 2015, at 1:41 PM, Job Snijders <job at 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 at 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
> 

Justin Wilson
j2sw at mtin.net

---
http://www.mtin.net Owner/CEO
xISP Solutions- Consulting – Data Centers - Bandwidth

http://www.midwest-ix.com  COO/Chairman
Internet Exchange - Peering - Distributed Fabric




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