[BC] Primer on Internet Streaming

[RichardBJohnson at comcast.net]

Anyone who anticipates using the Internet as a substitute for a program channel to his or her transmitter had better seriously think that over. It is well known that Comcast throttles what it thinks is excessive usage by dropping packets. This is an extreme annoyance when trying to download files and results in the impossibility of uploading any file in excess of about 10 megabytes. It also makes it impossible to update my Web Pages using any "store-bought" synchronization utilities because the result is the destination (hostmysite.com) protecting itself by disconnecting after it sees many missing packets requiring retries. I have to send individual files, one-by-one.

Now I find that Verizon DSL is doing the same thing! Who would believe that the turtle-crawl data rate one gets from a DSL line would cause the ISP to throttle data?

I can watch a FTP upload from a Windows machine to my Web Site from a Linux machine running 'tcpdump.' I can see the Windows machine resend about 10 percent of its packets. Then the retry amount goes to about 20 percent, and then the DSL modem's "Internet" LED will illuminate red and Verizon has kicked me off the Internet. The "DSL" LED remains illuminated and never flickers. Then I can read the log in the "Busy Box," the Linux-based DSL modem and find that link synchronization was never lost. It is just that the ISP killed me off, probably because its watchdog software felt I was using too much bandwidth. I have to switch off the modem and let it reboot and reconnect.

Streaming program data will likely have similar problems. Currently, ISPs configure for users' browsing Web Pages. If you do anything that looks like work, the ISP's software will start dropping packets. If this continues to "excess," the ISP will send (forge) a "FIN" packet, causing the user's connection to end.

Cheers,
Richard B. Johnson
Book: http://www.AbominableFirebug.com/