> -----Original Message----- > From: alto-boun...@ietf.org [mailto:alto-boun...@ietf.org] On Behalf Of > Salman Abdul Baset > Sent: Tuesday, June 02, 2009 9:57 AM > To: alto > Subject: [alto] 'Link capacity' in scope? > > > When a home customer purchases a [high speed] Internet plan from an ISP, > the ISP typically promises a certain upload/download link capacity for the > plan. > > In the old days of dialup, a device using a modem established a > point-to-point connection with the ISP and knew the link capacity which > was 14.4, 33, or 56kb/s. > > Increasingly, devices at home are connected to a WiFi router which in turn > is connected to a [A]DSL/cable modem. The devices no longer have a > point-to-point connection similar to dialup and cannot use the link > capacity estimate for WiFi router because it is completely different than > the link capacity between ISP and high speed modem. > > A device may run different application such as peer-to-peer applications > which need capacity estimates for voice relaying, p2p video etc. > > Currently, these applications must determine the link capacity by > performing measurements. Also, there is no way for applications to share > the capacity information with each other. > > My question is whether it is within the scope of ALTO to design a > mechanism to pass the link capacity, that ISP promised to the customer at > the time of the purchase of the plan, to the [A]DSL/high speed modem which > passes it to the devices upstream?
Well, DSL providers use dynamic spectrum management tools to adjust the bitrate/FEC on the DSL line. So, things (may) change over time. The DSL modem is aware of these provisioning changes, but all that stays in the link layer. I am not sure how you can get that from the app layer. Note that in newer DSL specs like ADSL2+, there is also seamless bitrate adaptation where the bitrate of the link will change based on the SNR. As you indicated, people use measurement techniques to figure out the link speed, etc. -acbegen > -salman > _______________________________________________ > alto mailing list > alto@ietf.org > https://www.ietf.org/mailman/listinfo/alto _______________________________________________ alto mailing list alto@ietf.org https://www.ietf.org/mailman/listinfo/alto
