Comment by AStonesThrow | Hacker News Reader

Comment by AStonesThrow | Hacker News Reader

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PSA: ISPs never, ever advertise download speeds. ISPs advertise signaling rates. The signaling rate is, e.g. 100Mbps for Ethernet. You won't get 100Mbps download rates on that Ethernet, because that's the Layer 2 signaling rate!!! If your ISP advertises "Gigabit Internet" they are advertising a gigabit signaling rate for their fiber optic service. Your download speed will always be less than your signaling rate, and it's up to you to figure that out.

Also recall that consumer agreements for Internet service never include a "CBR" or "committed bit rate". If you want your ISP to live up to a service contract, for availability and guaranteed download speeds, then you'll go to their Business-class unit and sign a contract for commercial service.

And you can prove that this is true: your ISP doesn't care if you can connect to anything except their head end. They will troubleshoot your modem, restart it, and work on the wiring between you and them, but they couldn't give a rat's ass if you can reach example.com or not.

I don't know what AT&T is doing, but they advertise 1Gbps and... https://i.imgur.com/B41zMRh.png usually they're pretty good.

They should be more transparent about what to expect, but realistically it's out of their control. They don't control Netflix's outbound traffic, for example.

Uhh this is exactly what GP is saying? If you went to the butcher, asked for 1lb of meat, they weighed it at 0.97lbs and still charged you for 1lb, you'd be upset.

The difference between 1,000mbps and 970mbps can (partially) be explained by protocol overheads.

I wasn't disagreeing with the parent poster. I was actually just surprised that my speed is as close as it is to the advertised speed. Normally 1 Gbps means something more like 600 Mbps.

There's a difference here though. The ISP isn't being nefarious if you don't get the advertised speed because they can't control anything outside of their network. The butcher, OTOH, presumably knows how to read a scale and can charge the appropriate price.

My ISP's advertised rate is the download speed I get during speed tests.

> ISPs never, ever advertise download speeds. ISPs advertise signaling rates.

I currently pay for 300Mbps symmetrical and actually achieve on the wire always greater than their advertised rates (for both down and up). And while I was doing the tests (today) multiple others were streaming and playing video games, so it's even more than I am seeing above.

Thanks for sharing this. It at least informs us of a nuanced definition of rates, but as other readers here have mentioned it does appear that actual byte-to-byte download and upload rates are both advertised and overdelivered by some ISPs.

Good to watch out for, though!

I use Xfinity with a gigabit plan, no fan of them for various reasons, but my "signaling rate" exceeds 1gbps at the physical layer in the cable modem and since I am using the 2.5 Gbps ethernet port on the modem my speed test slightly exceed 1Gbps usually 1.1 Gbps.

If you use gigabit ethernet out of the modem/ont then yes you will not see full gigabit speeds due to overhead. This is of course dependent on the type of connection you have and the equipment they use, so your broad statement is inaccurate.

> PSA: ISPs never, ever advertise download speeds. ISPs advertise signaling rates.

Not true of all ISPs.

And at some point, even if they are only advertising signaling rates, it's inconsequential.

I'm paying I think $70/mo for symmetrical gigabit. I just ran a speed test and got 922 mbps down, 910 mbps up. I'm not going to complain about that.

Can't edit my comment now, but I did get to wondering...

Does speedtest.net include packet headers in its speed? Assuming 40 bytes of a 1500 byte packet is from headers, leaving only 1460 bytes is available for application data, that means that a minimum if 2.7% of my bandwidth is packet headers.

So if speedtest.net is only counting application data and not compensating for the bandwidth used by headers, then I should at most see 973 mbps on my gigabit connection.

Our ISP advertises download speeds, and usually slightly exceeds them.

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