The FCC’s pending ruling against Internet Service Providers who manage their bandwidth in favor of fair access raises some questions. Here’s a list of questions rural ISP operator Brett Glass has raised.
Networking
The FCC’s pending ruling against Internet Service Providers who manage their bandwidth in favor of fair access raises some questions. Here’s a list of questions rural ISP operator Brett Glass has raised.
I wonder if any WISPs have considered something like a 128kbps,10MB token bucket; it’s neutral, it should satisfy light users, and it limits hogging.
Brett has a lot of custom-built and open source tweaks in his wireless routers, and I’m sure rate control is among them. I think part of the issue is that wants to allow occasional FTP and HTTP uploads but not persistent, hours-long random seeding sessions.
Hours-long seeding at 128kbps can’t cause that much congestion on a 10-20Mbps link, although I guess the transit costs could be substantial: 13GB/day. Hmmmm.
Depends how many people are doing it. If you have 20 on one cable segment, you’re going to get a lot of DOCSIS collisions, and if you are one of a small number of providers of a rare file piece, you’re going to have to field a large number of socket opens, each requiring a response.
The problem is more complex than that. There are actually TWO constraints on downstream equipment, whether it’s wired or wireless: bit rate and packet rate. (Due to the overhead in processing a packet, the packet rate becomes important when there are many small packets sent very quickly — such as by a BitTorrent tracker or seeder or by GNUtella’s UDP discovery mechanism. The latter can flood a network with requests for weeks or even months after the machine that was running GNUtella was shut down.)
It’s also worth remembering that if a user consumes constant bandwidth, it’s a constant and large cost to the ISP. At $100 per Mbps per month, an increment of 128 Kbps is $12.80. Our ISP makes less than $5 per customer per month, so that’s enough to cause a net loss on the customer.
Comcast has a point-to-multipoint network, where the most severe bandwidth constraint is on the upstream side. Consequently, they need to deploy a system that enforces fair queuing among bandwidth requestors. That’s tricky in DOCSIS, as a scheduling decision needs to be made in real time, but it’s not impossible.