Comcast Discloses Throttling Practices

Wired reports that Comcast finally provided information on its network management practices late Friday. In a report to the FCC (PDF), the cable company admitted to targeting P2P protocols Ares, BitTorrent, eDonkey, FasTrack, and Gnutella. Quoting: "For each of the managed P2P protocols, the [Sandvine Policy Traffic Switch] monitors and identifies the number of simultaneous unidirectional uploads that are passed from the [Cable Modem Termination System] to the upstream router. Because of the prevalence of P2P traffic on the upstream portion of our network, the number of simultaneous unidirectional upload sessions of any particular P2P protocol at any given time serves as a useful proxy for determining the level of overall network congestion. For each of the protocols, a session threshold is in place that is intended to provide for equivalently fair access between the protocols, but still mitigate the likelihood of congestion that could cause service degradation for our customers."

Comments

Re:Almost Worse than Legalese

[slimjim8094]

"For each of the managed P2P protocols, the [Sandvine Policy Traffic Switch] monitors and identifies the number of simultaneous unidirectional uploads that are passed from the [Cable Modem Termination System] to the upstream router.

Sandvine checks uploads without downloads. It does this 'above' (in the hierarchy) from the head-end of the cable network (neighborhood box).

Because of the prevalence of P2P traffic on the upstream portion of our network, the number of simultaneous unidirectional upload sessions of any particular P2P protocol at any given time serves as a useful proxy for determining the level of overall network congestion.

P2P is used a lot, and fairly consistently. Therefore, the number of one-way uploads (not SSH or rdesktop like somebody else said) can be used to extrapolate the total congestion for much less 'thought' (for Sandvine)

For each of the protocols, a session threshold is in place that is intended to provide for equivalently fair access between the protocols, but still mitigate the likelihood of congestion that could cause service degradation for our customers."

We count the number (like, only 500 BitTorrent sessions) and cut off after that.
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My thoughts: I don't think this helps anything. I doubt anybody has much of a problem with them legitimately throttling P2P protocols, as long as it's done consistently and fairly (no need to throttle with plenty of upstream, right?). The real problem are the RSTs which impersonate each side of the connection to the other, saying that the other closed the connection. That's like Bob passing messages between Alice and Candice, and telling Candice that Alice called her a bitch, and telling Alice that Candice called her a bitch.

QoS isn't that hard, and I'm sure they know how. It's fairly easy to throttle back without sending RSTs, and allows for the full utilization of 'open' bandwidth.

This statement explains the rationale, but not the choice of methods.

Re:Evil from cable companies? Nevar.

[not_anne]

Comcast hasn't advertised "unlimited internet" in many years. After a Google search, the only use of "unlimited" I could find in a current Comcast ad was associated with their phone service: "Make unlimited local and long distance calls with 12 popular features..."

Re:Now what will happen?

[Triv]

From the FAQ:

How is this announcement related to the recent 250 GB monthly usage threshold?

The two are completely separate and distinct. The new congestion management technique is based on real-time Internet activity. The goal is to avoid congestion on our network that is being caused by the heaviest users. The technique is different from the recent announcement that 250 GB/month is the aggregate monthly usage threshold that defines excessive use.

Gizmodo's take on the thing is much easier to read.

Going over the 250GB cap will get you disconnected, but your bandwidth will get throttled long, long before that if you do anything their software deems "excessive."

Re:Evil from cable companies? Nevar.

[ZorinLynx]

The thing is, time is no longer an issue in modern connections because they are packet-switched down to the bare wire.

In the old days you used a phone line, which was circuit switched, to call your ISP. They had a limited number of ports so they had to limit how long you could be online, otherwise folks would get a busy signal.

Since these days there is no customer-initiated circuit switching involved in cable and DSL links, the concept of "unlimited" can *only* apply to data transfer. There isn't anything else to limit.

Believe me, I remember the days of circuit switching and "hourly limits" quite well. I was on an ISDN connection from 2000 to 2004. Worrying about how *long* you're online is extremely irritating. Those are definitely "good old days" I wouldn't want to go back to.

what about when speakeasy lies to you?

[ClioCJS]

What about when you chat with pre-sales people and they tell you you can use 100% of your bandwidth 100% of the time, and then Speakeasy terminates you for downloading too much. Happened to me.

There ARE people lying out there. Plenty.