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). That sounds too aggressive for the middle mile. Dont you think so? On Sat, Aug 15, 2015 at 10:51 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.
YMMV.
Owen
On Aug 15, 2015, at 10:07 , Glen Kent <glen.kent@gmail.com> wrote:
Hi Bill,
Just making sure that i get your point:
Youre saying that the probability of packet drop at peering points would roughly match that at the edge. Is it? I thought that most core switches have minimal buffering and really do cut-through forwarding. The idea is that the traffic that they receive is already shaped by the upstream routers.
Glen
On Sat, Aug 15, 2015 at 10:33 PM, William Herrin <bill@herrin.us> wrote:
On Sat, Aug 15, 2015 at 12:47 PM, Glen Kent <glen.kent@gmail.com> wrote:
Is it fair to say that most traffic drops happen in the access layers, or the first and the last miles, and the % of packet drops in the core are minimal? So, if the packet has made it past the first mile and has "entered" the core then chances are high that the packet will safely get across till the exit in the core.
Hi Glen,
I would expect congestion loss at enough peering points (center of the core) to put it in the same league as noisy cable at the edge.
Regards, Bill Herrin
-- William Herrin ................ herrin@dirtside.com bill@herrin.us Owner, Dirtside Systems ......... Web: <http://www.dirtside.com/>