NDPCom
07-18-2004, 07:22 PM
Could somebody explain to me what is meant when host4you say
We use 95%ile, not average
The 95th percentile is the smallest number that is greater that 95% of the numbers in a given set. The amount of Burstable Bandwidth is derived from the 95th percentile calculation described below. The 95th percentile calculation is based on industry standard 'Base 10' method where 1 Kbyte equals 1,000 hits. The Committed Access Rate bandwidth will be invoiced as Fixed Charges in accordance with the payment. The Burstable Bandwidth Charge described below will be invoiced to the Customer as a Variable Charge in accordance with the payment and is in addition to the Flat Rate Billing for the selected plan/Committed Access Rate.
We pools the routers for Customer ingress and egress usage at five-minute intervals. The higher usage number for each poll is stack ranked. The top 5% of the usage number is discarded. The next higher measurement is the Burstable Bandwidth.
The reason we do 95th%ile now is it helps us with capacity planning and management. 95th%ile represents how much of your capacity you are really using and helps us plan for upgrades, etc. If we billed usage on average it makes it difficult to look at what we are billing you and ensure we have enough capacity available so there is greater risk in average billing. For instance, you could push 500 mb on day, 20 mb the next day, etc and at the end of the month, the average would be 260 mb. So when we look at the forecasts for what customers are doing we run the risk of oversubscribing our access layers. This isn't typically a big deal until a DDoS attack starts rolling in or another customer starts doing an abnormal amount of traffic then an oversubscribed access layer will start to affect everyone connected to that access router.
The average in + average out number will typically be lower than 95th%ile in a month. How much lower depends on your usage pattern. If you push a constant amount over the ckt then 95th%ile and average look the same. If you have bursty traffic, which most everyone does, then the 2 will vary. I've seen values where the ration of (AveIn+AveOut)/95th%ile ranged anywhere from 2 to .65. The reason for this is that we need to have capacity available to you to handle your bursts in traffic. If we didn't have capacity available, then when you burst, you would drop packets and this would make neither of us happy. 95th%ile provides us a fair way to measure your traffic and bill you for the percentage of the network you actually need to move the traffic you do without affecting your performance.
Thankyou in advance
We use 95%ile, not average
The 95th percentile is the smallest number that is greater that 95% of the numbers in a given set. The amount of Burstable Bandwidth is derived from the 95th percentile calculation described below. The 95th percentile calculation is based on industry standard 'Base 10' method where 1 Kbyte equals 1,000 hits. The Committed Access Rate bandwidth will be invoiced as Fixed Charges in accordance with the payment. The Burstable Bandwidth Charge described below will be invoiced to the Customer as a Variable Charge in accordance with the payment and is in addition to the Flat Rate Billing for the selected plan/Committed Access Rate.
We pools the routers for Customer ingress and egress usage at five-minute intervals. The higher usage number for each poll is stack ranked. The top 5% of the usage number is discarded. The next higher measurement is the Burstable Bandwidth.
The reason we do 95th%ile now is it helps us with capacity planning and management. 95th%ile represents how much of your capacity you are really using and helps us plan for upgrades, etc. If we billed usage on average it makes it difficult to look at what we are billing you and ensure we have enough capacity available so there is greater risk in average billing. For instance, you could push 500 mb on day, 20 mb the next day, etc and at the end of the month, the average would be 260 mb. So when we look at the forecasts for what customers are doing we run the risk of oversubscribing our access layers. This isn't typically a big deal until a DDoS attack starts rolling in or another customer starts doing an abnormal amount of traffic then an oversubscribed access layer will start to affect everyone connected to that access router.
The average in + average out number will typically be lower than 95th%ile in a month. How much lower depends on your usage pattern. If you push a constant amount over the ckt then 95th%ile and average look the same. If you have bursty traffic, which most everyone does, then the 2 will vary. I've seen values where the ration of (AveIn+AveOut)/95th%ile ranged anywhere from 2 to .65. The reason for this is that we need to have capacity available to you to handle your bursts in traffic. If we didn't have capacity available, then when you burst, you would drop packets and this would make neither of us happy. 95th%ile provides us a fair way to measure your traffic and bill you for the percentage of the network you actually need to move the traffic you do without affecting your performance.
Thankyou in advance