On 28-Mar-2009, at 16:00, David Robb wrote:
On Sat, 28 Mar 2009, Brian E Carpenter wrote:
I said earlier that I prefer there to be enough bandwidth. But when there isn't?
When there isn't enough bandwidth then QoS is a temporary solution. The answer is to get more bandwidth. Otherwise you're making the choice between delaying or dropping lower class traffic, and eventually[1] that'll impact on the performance of that class sufficiently that those using it will give up.
It's perhaps easier to see that this is the case if you use the phrase "selective throwing away of customer packets" instead of "quality of service". The goal of an ISP is surely to deliver packets for customers and bill them for doing so. Nobody wants to throw away customer packets if there's a way to avoid it. Nobody wants "quality of service" if there's a way to avoid it.
For short term problems eg abnormal traffic flows causing congestion, sure. For long term traffic management - get bigger tubes.
Amen. Joe