Quite the inverse, I'd say; most of the capacity headaches center around the handoff between networks, and most of the congestion points I come across are with private peering links where one party or the other is unwilling or unable to augment capacity. The first and last mile are fine, but the handoff between the networks is where congestion and drops occur. As others have noted, this will vary greatly depending on the network in question--so asking a broad community like this is going to yield a broad range of answers. You aren't going to find one single answer, you'll find a probability curve that represents the answers from many people running different networks. You'll find the location of packet drops tends to shift depending on where companies are willing to spend money; some companies will spend money on the access layer to ensure no drops happen there, but are less willing to pay for capacity upgrades at peering handoffs. Other networks will short-change their access, but maintain a well-connected peering edge. So--short answer is there is no one answer to your question. Collect the different answers, plot the curve, and decide where along the curve you want *your* network to land, and build accordingly. Nobody has infinite money, so nobody builds to a level to ensure zero loss probability to every destination around the planet. Matt On Sat, Aug 15, 2015 at 9:47 AM, Glen Kent <glen.kent@gmail.com> wrote:
Hi,
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. Sure once it gets off the core, then all bets are off on whether it will get dropped or not. However, the key point is that the core usually does not drop too many packets - the probability of drops are highest in the access side.
Is this correct?
Glen