 RARPSL
join:1999-12-08
Suffern, NY | Throttling vs Capping As noted in the article a supposed OOL tech claims that OOL throttles not caps. He is incorrect in that OOL does both.
Capping is the act of telling your modem that its maximum upload speed is lower than normal. When you power up the modem and it connects to the OOL network, the network sends a set of settings to it that tells it, along with other things such as what IP Address it is to use, how fast it is allowed to download and upload. When you are capped, your modem is told via these settings that instead of being allowed to upload at 2Mbs, it is to upload at 512Kbs. Thus being capped is a permanent restriction (at least until a new set of settings is sent that ups the Upload speed back to "normal").
Throttling on the other hand does not restrict the speed that the modem is allowed to upload/download at. What it does is slowdown the speed that you are CURRENTLY sending/receiving at by slowing down your receipt of the acknowledgment of your data. When data is sent, the other side says "It got here, send more" and until that "OK acknowledgment" arrives no more data will get sent. Thus by slowing down the acknowledgment delivery the speed at which data is being sent can be throttled. When you are uploading, the delivery to you of the acknowledgment is delayed by your ISP, while when you are downloading, it is the sending of your acknowledgment that is delayed. Sometimes the throttling is done only for certain types of activities (when the node is stressed) such as P2P/BitTorrent in which case the throttling is referred to as "Traffic Shaping." Throttling (as opposed to Capping) thus only kicks in when there is too much load at your node and you are doing something that is stressing the node and stops when the load on the node is reduced (think of it like driving and the speed limit is 55MPH but it is rush hour and there are so many cars on the road that you are only able to go at 20MPH). |
