Some truth about Comcast - WikiLeaks style

Rettke, Brian Brian.Rettke at
Tue Dec 21 13:31:27 CST 2010

--"Congestion == oversubscribed.  I would love to see a public posting or notice or something on my ISP's website showing current flows and congestion (the Cacti driven Network Weathermap is one such tool I've seen networks use; one of my providers used to have one publicly available, and it was very useful).  Would make it much easier to make informed decisions on my part.

But this CMTS subscriber wanting to do medium-low bandwidth H.323 never had trouble seeing our stream to him; that was the funny thing.  It was always the return stream from him to us that broke up.  And it didn't act like congestion; it acted like some sort of filter in place that would only allow the full upstream briefly, and then would die for some period of time, and then would allow another burst of traffic.  (I've received one private reply mentioning a possible technology to do this....)

Many if not virtually all residential broadband subscribers are under the impression that they really get the full use of the advertised bandwidth; it is a shock to most when they learn about oversubscription practices and QoS congestion management."---

        I'm not sure you can speak for the majority of all subscribers, but it's fair to assume that people who are not used to "checking under the hood" before making a purchase are of that mind. And congestion does mean oversubscribed, but that's a rather narrow argument. You are buying a shared service, which never guarantees full use of anything. The reason that you pay ~$100 instead of 5-10 times that amount is that you are buying a time share.  You do not own or lease any part of your connection. It is the advertising and marketing of such things that generally leaves the consumer clueless unless they do their own research.

        Being that this is NANOG, and the expectation is that this community is the cognoscenti, I'd say we can dispense with the marketing. If you use a cable modem or DSL service, your expected use is entertainment. Depending upon your neighborhood, and the amount of people that latch onto a trend, you will see oversubscription, because no one ever builds supply that will far exceed demand in an instantaneous manner.

        If you expect your service to not be oversubscribed, you need to drop your modem for a leased line service. The SLA guarantees you get what you pay for. If the contrary argument is that you pay enough for your service, we need to define the costs of implementing your end-to-end service, and the difference between that and what you pay.

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