Comcast and Net Speed Tests

JimDaGeek writes "I recently moved to Columbia, SC where I have Time Warner as my cable ISP and pay for an 8 Mbps connection and have been very happy with the service, speed, and reliability. In contrast I have heard bad things about Comcast. So now that I am up in the Philadelphia PA area visiting my parents, I decided to test out the speed and reliability using the Speakeasy speed test. The results surprised me. Here are the reported download speeds in Kbps: New York, 18,946; Washington, 15,821; Atlanta, 11,257; Chicago, 10,042; San Francisco, 4,230. What is going on? I know my father is not paying for a 10+ Mbps connection. Is Comcast giving priority to popular speed-test sites?" From Comcast's site, in the Philadelphia area they seem to offer download speeds of 6 or 8 Mbps, with an option for a "PowerBoost" to 12 Mbps on large files. This wouldn't explain the results JimDaGeek got of almost 19 Mbps down.

Update: 07/10 12:07 GMT by KD : A friend in Massachusetts had a tree fall on his house. The Comcast guy who reconnected the lines told him that they are boosting the line speed to 20 Mbps down / 2 Mbps up in certain areas to be more competitive with Verizon FiOS.

SpeedTest.net

[ragnarok]

The Speakeasy speed test is just a re-branded version of speedtest.net [speedtest.net]. They have a lot more test locations to choose from there.

Re:SpeedTest.net

[Lumpy]

and it's a worthless test.

One big transfer != bandwidth capabilities.

Give me 100-500 smaller files with smaller ACK going back. that gives you a real test that will show latency and jitter.

also check many different ports. Port 80 get's priority. Ports above 8000 get lower priority. Ports for Voip are screwed with hard.

REAL BANDWITH TEST

[logik3x]

http://miranda.ctd.anl.gov:7123/ [anl.gov] Can't stand seeing people using speedtest.net, MOD THIS UP!

Re:

[Kamokazi]

I think THEY just got a bandwidth test...

Re:

[X0563511]

And further down are links to other systems... most are working

Re:

[s0l0m0n]

15930 seconds, and crashed my browser!

Great app.

Re:

[timeOday]

Ports for Voip are screwed with hard.

I'm on Comcast and dropped my home line for Vonage about two years ago, and in my case it works very well. I don't like Comcast's pricing, since Cable+Internet alone run $100/mo. Ouch. And sometimes I'd like a higher upstream bandwidth cap. But the fact is (for me) the high-speed internet works pretty darn well, both reliability and speed.

Re:

[eli pabst]

Give me 100-500 smaller files with smaller ACK going back. that gives you a real test that will show latency and jitter.

For the average joe the main content where bandwidth is going to be an issue are things like an html file, audio file, video file... all effectively one large file. They don't care about jitter, just that their homepage loads 10x faster. Obviously it's not a complete metric, but for most people it's a reasonable measure.

Re:SpeedTest.net

[Anonymous Coward]

bandwidth != latency. You want both (high bandwidth and low latency, that is), but that doesn't make them equal.

Time of day?

[carlivar]

Since cable bandwidth is shared, wouldn't the time of the test matter? I've noted (very unscientifically) that my Internet seems slower between roughly 7-9pm (on Charter in Los Angeles area).

Re:Time of day?

[catwh0re]

It also makes me think of how complicated the simple "bandwidth test" will be should net neutrality get thrown out the window.

Already we juggle the factors of location, "paid for speed", shared bandwidth issues with daytime or peak traffic.. but then without some kind of neutrality we'd also be juggling whether or not the interconnects between yourself and the test site are all on a higher priority or lower priority pipe.(something we could never know)

Today your ISP can blame a bit of the slowdowns on network conditions, but ultimately it's obvious if your ISP is a slower provider.. but in the future they'll be able to knowingly serve you slow speeds while claiming it's just the low-priority sites you may be visiting.

Re:

[Deliveranc3]

Obvious vs proof, I live in Canada I've noticed my ISP (Rogers) limits bit torrent (specifically uploading to a single peer is 40-70KBps while multiple peers get 2-10KBPS)... How would I prove that?

There is already significant throttling going on, why wouldn't they prioritize some traffic very highly, simply cache the site and show your last mile bandwidth.

Totally underhanded, but these are fooking telecos

Re:Time of day?

[lancejjj]

Since cable bandwidth is shared, wouldn't the time of the test matter?

FYI, practically all internet traffic traverses shared communication lines. The point-to-point connection of DSL becomes shared as soon as your local copper pair is squeezed onto a multiplexed line, within a few thousand feet of your home.

Re:Time of day?

[ivan256]

Yes, and your cable connection uses a shared upstream connection once it reaches the CO too. The difference is that the "last-mile" connection is also shared. Either can become a bottleneck depending on traffic.

Of course the internet traverses shared lines. That's practically the point of the internet.

Re:

[QuietLagoon]

The point-to-point connection of DSL becomes shared as soon as your local copper pair is squeezed onto a multiplexed line, within a few thousand feet of your home.

True, however, it is always easier (and less expensive) to add additional capacity in a central office than it is for a cable company to add more lines within a bottlenecked neighborhood.

Re:Time of day?

[MrShaggy]

Since cable bandwidth is shared, wouldn't the time of the test matter? I've noted (very unscientifically) that my Internet seems slower between roughly 7-9pm (on Charter in Los Angeles area).

I look at the difference between cable and dsl as 2 different ways of getting to a train-station.


Cable might be like taking a bus to the station. There might be other people there. However, its not that significant.


Dsl is like taking your car or a cab to the station. It definitely is not a shared ride into the station.


The one thing that happens is that everyone gets off of there rides, and they all take the train out. Pretty much at the same speed.

Of course during that time of the day there are many people on the internet, so it won't matter what you are using. Its somewhat insignificant how 'slow' it is. The only thing that kills the dsl is how far away you are from the office. Thats pretty wild. The thing is that you can get speed tests from eith side of the country or even planet. So even if it isnt the rush hour here, it will be elsewhere.


Thats why I think most dsl ads are so misleading.

Re:

[dbitter1]

Cable might be like taking a bus to the station. There might be other people there. However, its not that significant.

Unless your bus is, say, giving away free money/crack/heroin/whatever and starting in a high-density housing project. Then it would be a ride like my former.

In Chicago, Comcast acquired their monopoly from several other smaller cable companies. The one I had apparently had some pretty sleazy workings- the cable modem appeared to be in some sort of bridge mode, as I could see ARP requests from other modems. For one weekend, I counted over two thousand unique MAC addresses worth of ARP requests.

And the type

Re:

[StikyPad]

The internet is not a truck!

Re:

[livewire98801]

Wonder if there's a way to spoof the TFTP source. . . or make it download from the LAN interface instead.

Yes, I'm a schemer. This is also academic, since I'm on DSL :)

Re:

[timeOday]

I've noted (very unscientifically) that my Internet seems slower between roughly 7-9pm (on Charter in Los Angeles area).

All the servers are more busy then, too, so who knows?

Re:

[kaufmanmoore]

Facebook and myspace can eat bandwith with all the crap some people post.

Re:Time of day?

[Firehed]

You remind me of the time that I single-handedly saturated half the pipe for the entire school with a couple of unusually fast torrents. Oh, what I wouldn't do for a personal T3...

Re:Time of day?

[Matey-O]

Oh, what I wouldn't do for a personal T3...

What, short of paying money for it?

Re:Time of day?

[CopaceticOpus]

What, short of paying money for it?

Dude, a T3 would be almost as expensive as just buying all those CDs and movies.

:)

Re:

[Short Circuit]

That's nothing. I was in a vacant computer lab in Michigan during Spring Break, pulling Debian CD images from an FTP server in Germany (best transfer rate I could get; Jigdo never worked for me, and there weren't official torrent trackers at the time. {Are there now? Switched to Ubuntu a couple years back.})

The door to the lab bursts open, and a couple techs started methodically checking port labels on all 69 of the PCs, then started checking the Macs. (I was on a Mac 'cause those were the only machines t

Re:

[Short Circuit]

this is because even if programs aren't using bandwidth networks use a csma/cd "carrier sense multiple access with collision detection" setup where, simply put, if someone is transmitting on the line, you back off and wait to transmit.

While that's technically in the Ethernet standard, you don't see it much--if at all--with switched networks, and even less with networks with decent switches that hold packets in a queue. Switches and routers aim to eliminate that kind of inefficiency.

Re:

[livewire98801]

Technically he's correct. Cable by it's very nature is half-duplex. That's why we quit using thick/thinnet on LANs. Yet Comcast pitches it as the best internet connection available.

Thats why DSL and Fiber (okay, that one is obvious) are always better technologies than cable for last mile, no matter how much bandwidth you throw at it. Unless you're Verizon, and don't add another T to the DSLAM until you have a higher churn rate :-/

Giving Comcast Props

[tenchiken]

It kills me to say something nice about the brood of bloodsuckers that are Comcast, but I can verify that Pockets of Comcast's net are seeing huge increases. In particular, I have seen speeds of 19-22Mb/s burst to testing sites, and almost 2.0MB/s non-bursting.

That's in the Denver region using both speedtest.net and DSL tools.

Give credit where it's due, but Comcast does appear to be amping up the bandwidth hugely.

Between this and the Zimbra announcement, Comcast has firmly passed Qwest as next to last evil corporation.

Re:

[Icarus1919]

To everyone patting Comcast on the back for a few scattered examples of decent, above board service, I advise you to check [consumerist.com] The Consumerist [consumerist.com] for a bit more information on Comcast's practices.

Re:

[Novanix]

Actually I get really high burst speeds, but if you a long download of >10-15 seconds it will drop to your 6-8 megabits a sec rate. It confuses all the speed testers as basically any large transfer for the first so many seconds will go very fast, and its just after that the speed really drops. Best way is to just downlod a large file and see what the speeds are like 20 seconds in.

Re:

[timeOday]

20 mbit burst a big bonus for apps like google maps. At a hotel recently I noticed maps was awfully sluggish, but checked and realized I was pulling half a megabit, which used to be quite a bit of bandwidth! Even cnn's homepage is most of a megabyte. Man, the web has really gotten bloated. Any dial-uppers out there? How do you do it?

Re:

[dreddnott]

I've been using dial-up at home for all of ten years. They won't even pave our frontage road let alone string cable or DSL out here.

How do I do it? Well, I suppose I'm just used to it. I'd say I use Opera to cope, as it's such a snappy, efficient browser, but I've been using Opera for at least eight years (version 3.something), since before the Internet was bloated, so I guess that doesn't count. I do set the Opera caches to their maximum sizes to minimize the horror of redownloading the static content of w

Re:

[MBCook]

I have Comcrud. They bought out my local cable company years ago and raised rates, trashed service, capped the internet speeds, and all sorts of other fun stuff. I have something like a 6 mbps connection if you listen to them. I've seen it up as high as a little over 1 mbps (from speed tests and such). As it is now, every speed test I can find is maxing out at about 300 kbps down and 350 kbps up, which is what I was getting hours ago when this story first hit the firehose.

Jerks.

I love monopolies. My only

Re:

[Firehed]

As a slashdotter, I doubt it, but could you have confused Mbps with MBps?

When I was on Comcast (actually, come to think of it, I think I am here too), I usually got speeds right around what was advertised. Hell, I got a speed boost when they took over Adelphia.

Re:

[MBCook]

We asked. We had a little local outfit that was great. Then Comcast bougt them out. We've changed our plan once or twice (like adding HD when I got an HDTV, and lowering the cable speed since we were no where near that speed). Things have gone quite downhill, but they didn't do that do us. As I said in my above post, we have service with them because they are the only game in town for us.

Re:

[iamdrscience]

I can verify that Pockets of Comcast's net are seeing huge increases. In particular, I have seen speeds of 19-22Mb/s burst to testing sites, and almost 2.0MB/s non-bursting.

I've had Comcast and I found their download speeds to be quite usable and the occasionally help of burst speeds like you mentioned is nice as well. However, their home service is still only available with 40kB/s (320kbps) upload bandwidth which is shit. And to make things worse, it seems that the more of that upload bandwidth you use, t

Re:

[Eric in SF]

Two things:

I have Comcast (8/768) in Cole Valley, San Francisco, and I have also noticed the speed increase. Uploads to my website are now cruising at 140kb/sec, occasionally dropping to 90kb/s. No complaints here! I performed a dslreports speed test recently and it also reported some Korean or Scandanavian-class bandwith numbers - the highest I've certainly ever seen in my time with broadband.

Second - it's my understanding that as you saturate the uplink connection (max out uploading a file) on a consumer-

Re:

[Blkdeath]

Second - it's my understanding that as you saturate the uplink connection (max out uploading a file) on a consumer-grade connection/router, you interrupt the normal control-channel "Chatter" of web browsing. Basically, the "I got it" packets are stuck due to the saturated uplink, and you don't get the next packet until the acknowledgement makes it.

Actually you're absolutely right. Any TCP (connection based) protocol will suffer from a saturated uplink to the point where it can become unusable depending

Re:

[Tuoqui]

I'm a bit skeptical on this...

It could just be that they are using QoS and Packet Shaping to speed up connections to these 'test sites'. Allowing for 'bursty' traffic to break formal limits for 5, 10 or even 60 seconds a test takes. This makes people happy going 'Hey cool I'm getting X-speed here when I'm only paying for Y-speed'. A customer placebo if you will.

That is the problem with net neutrality not being respected by ISPs, they can engage in these sorts of behaviors without anyone knowing if they're g

Re:

[pen]

The bursts of traffic are not designed for the test sites. Most people don't care about the test sites. They're designed for downloading that 5MB Word document or PDF that someone e-mailed you or linked you to.

Caching?

[beaverbrother]

Perhaps the speed tests are used frequently enough for their system to cache it automatically?
As long as it isn't special treatment for the test sites, it is hard to blame Comcast for the speed boost.

Re:

[jlarocco]

Give credit where it's due, but Comcast does appear to be amping up the bandwidth hugely.

I got a massive bandwidth increase for about a month right after Comcast took over Adelphia and started blocking bit-torrent. So don't get too excited, they're just using the increased bandwidth to hide the fact they're breaking your service somewhere else.

Re:

[vought]

In particular, I have seen speeds of 19-22Mb/s burst to testing sites, and almost 2.0MB/s non-bursting.

I have seen fairly consistent rates in Silicon Valley (San Jose) of 14-19Mbps on Comcast's basic Internet service.

Only 1.5Mbps up.

Re:

[AaronW]

I just ran the test and got 21,499Kbps down and 601Kbps up, at 7:45pm from Fremont to San Francisco. Granted, I pay an extra $10/month for more bandwidth (for more upstream bandwidth) but lately I've noticed a nice improvement in downstream bandwidth, given that it's supposed to be 8Mbps. I'm not complaining.

Re:

[dabraun]

I have to give Comcast props as well. I haven't used speed test sites, but I've observed my download speed for actual files I want, go from a few hundred KB/sec to over 1MB/sec in the last few years. Ok, I realize that this isn't as dramatic as what some are reporting, but I'm getting what I believe is about 12mbit/sec when I originally signed up for something more like 3-4mbit/sec - and all the while the price has not changed. Sure, it's a little slower in prime time of the evening, but it's still quite

Re:

[whoever57]

I have also seen good speeds (>15Mbps) when downloading using Comcast. However, upload speeds can be problematic. Just today, I was uploading using sftp and it started out at 150kBps and quickly dropped to ~40kBps (somewhat greater than 320kbps, depending on the overhead)

I have also seen slow ssh speeds to my work LAN, yet when I go via an external server, the ssh speed is much better.

Who cares about peak rates?

[ivan256]

My problem with Comcast was never how fast it could be. It was the frequency at which it wasn't working at all.

When they work on reliability, up-stream, and price, then maybe they'll deserve some "props". For now, Fios is kicking their ass up and down the block. Even these theoretical burst rates can't compete, plus Fios is cheaper and more reliable. Sorry Comcast.

Re:

[tenchiken]

Which is why I documented non-burst speed above.

Re:

[AaronW]

I have had few problems with Comcast. It is not unusual to get over 1.5 megabytes/second when downloading large files from a fast site. It's expensive, but much faster than the competition around here.

The speed test reported 21,499Kbps down and 601Kbps up.

Re:

[symbolic]

I have Comcast, and I also had a BAD resetting problem - I'd get reset on almost every game I tried to play. Sometimes I'd make it through a couple of hours, but those were usually the exceptions. In looking at all possible causes, I upgraded my router's firmware, and all my problems disappeared. It appears as though it was the damned Linksys router causing the problems.

Good Speeds

[GizmoToy]

Those are some pretty damn good speeds. I was lucky to get 4Mbps at Time Warner when their max was 6Mbps. I switched to a 5Mbps DSL connection which ended up being faster. I wonder if there's much of a difference now that they bumped it up to 8Mbps. And it seems with Comcast apparently bumping up to 16Mbps according to another poster, a connection speed race could be on. Maybe it's time to look into switching back?

Well thank god we still have TW in Raleigh

[gelfling]

What with their rock solid 3.7MB down and 374KB up - Anything more would be Goddamn communism.

Re:

[kaufmanmoore]

TWC, Bellsouth and Clearwire.....NC is still in the dark ages, not 1 offering of double-digits down or even 1mbit up.

rather nice if you really have that

[r00t]

Lots of places get many MB up, but only 128 kB down! This is no good for videoconferencing. The 128 kB is bad enough to affect downloads even, because TCP ACK packets can't get back fast enough.

374 KB, especially if "rock solid" (no VoIP dropouts unless you go above, low latency, reliable 24x7 operation) is great.

probably not fibbing

[SocietyoftheFist]

I had 6Mbps service through them several years ago and routinely downloaded ISOs at 10Mbps.

DOCSIS 2.0 Plus

[Fallen Kell]

It all depends on the cable modem that you have. Some of the new motorola modems, like the SB5120, do not have the ability for Comcast to limit as much as they sometimes like. Comcast themselves has not been too worried about it as long as the network segment you are a member of is not over-crowded. They see it more like a new benefit which allows better competition against FIOS. Personally I average 25-28mbps on my modem.

Here is a current snapshot:
[speedtest.net]

Re:

[Fallen Kell]

DOL... forgot the link is a pic/link... well, it was 20,000+ down, 1,500+ up...

Re:

[hansamurai]

So are you using the SB5120 then? Is it worth the 50 bucks at Amazon or Newegg? I torrent a lot with moderate internet surfing.

Re:

[Fallen Kell]

Yes, I have that modem myself. I went from an older model that Comcast upgraded me to when they upgraded to 6mbps in the area. It was an older motorola surfboard modem. A friend at work read about the SB5120 and upgraded to it and showed me the results, which were dramatic for him. He was seeing 30mbps at times. I then purchased one for myself. I did speed tests before and after the change. I went from seeing approx 8mbps down and 320kbps up to 28mbps down and 1.5mbps up. This was over the difference of a 1

Re:

[JimDaGeek]

Why would the cable modem make a difference? Wouldn't the ISP's be doing the throttling based on your MAC address?

I recently upgraded my 5 Mbps TW cable connection to 8 Mbps for an extra $10/month. Within 1 minute or so, I had the faster speed. When I called they just asked me for the MAC address on my cable modem.

Well...

[Creepy Crawler]

Try a real-life saturation test: Bit Torrent.

Tell whatever client you're using to go all out.

If they block it, use Jidgo to download ALL of Debian (but that only tests download, not upload).

Re:

[JustNiz]

No its no good using p2p. Most if not all the ISP's do traffic shaping (read: bandwidth throttling) on p2p traffic.

Re:

[account_deleted]

Comment removed based on user account deletion

PowerBoost uses compression

[rdean400]

I'm wondering if the speed test uses a data block that is more compressible.

not compression

[r00t]

Sending the bits is easier than compressing them. Compression is not as simple; it takes compute power and time.

Probably they just allocate an extra (second or third) channel to you on demand, maybe with something to keep you from having it continuously.

PowerBoost

[the_cowgod]

The Speakeasy test regularly reports over 20Mbps on my Comcast connection. The "PowerBoost" feature allows basically uncapped speeds for the first ~15MB of a transfer, then it drops down to the normal 6Mbps. I can easily see this effect when doing large downloads with my UsenetServer account. It does inflate speed test results, but Comcast does not appear to be favoring the test sites in any way.

Faking performance?

[lancejjj]

In contrast I have heard bad things about Comcast. So now that I am up in the Philadelphia PA area visiting my parents, I decided to test out the speed and reliability using the Speakeasy speed test.

I've seen the same thing in the other Comcast markets (but not all over). What would it take for Comcast to throttle all traffic except that going through Speakeasy's "speedtest" IPs? I'm imagine very little, and it likely could make some people feel good about Comcast's performance. That's not to suggest that Comcast is actually faking it - I'm just saying that it could be done. Clearly, Comcast wouldn't do this - it'd be a stupid risk for them.

In any case, maximum download throughput is only a part o

Re:

[musicmaker]

If you only pay $55/mo in electric you must be living in either a very small place, or somewhere where electricity is unbelievably cheap.

I swear to God

[Travoltus]

Comcast had boosted us up to 28mbps download speeds according to Speedtest.net. I routinely confirmed it with download speeds of around 2.9 megabytes per second of total incoming download bandwidth during quieter times of the day (midday, night time). I should have been getting 3.5 megs per second, but I attribute the difference to a shiteload of 24/7 Youtube-like traffic.

They said they were doing some kind of trial in my area, and that it would end.

Well, it did end, and I went back down to a max performanc

Download a linux distro

[Raleel]

Someone above mentioned using jigdo to get all of debian, but even using wget to get a full dvd or cd set of some distro will provide you with a good data point. That's been my standard test for quite a few years now.

Re:

[grcumb]

Someone above mentioned using jigdo to get all of debian, but even using wget to get a full dvd or cd set of some distro will provide you with a good data point.

I beg to differ. Downloading a single file is only indicative of how fast a particular connection is between two particular points. P2P, if it's allowed to, saturates the network with two-way traffic to numerous end points. If - and this is a big if - there were no constraints on P2P traffic at large on our networks, I would consider it a near ideal measure of TCP traffic capacity in the real world.

In fairness to your comment, you characterised that single download as a 'data point'. Strictly speaking,

In Bay Area try Apple.com

[toonerh]

They have lots of 10's to 100's of MB downloads that are compressed already, so provider compression won't help. Of course if the file is in a squid cache, nothing upstream matters. (download Mac OS X 10.4.3, not iTunes 7.3).

Comcast in Washington DC

[Southpaw018]

I have Comcast in the DC Metro area (Maryland side). Just ran a test, and I got 5856 down and 363 up to the DC server at Speedtest. My connection is advertised as 6Mbit - seems to be spot on.

Re:

[maotx]

I do as well (Greenbelt.)
Speedtest.net tested against Frederick, MD ~13Mb down.
Sites just a little further away, such as Ohio, give me ~5Mb down.

Too bad Comcast doesn't do much for the upload

[CrazyJim1]

50k/sec upload suuuuuuuucks. At least make it 128k/sec like other broadband. The reason I care is that I'm making a P2P video game, and I have to go with the slowest upload for broadband: Comcast's 50k/sec upload. If it went to 128k/sec upload, my game could support 2.5x as many players!

Mysterious speeds

[suv4x4]

The results surprised me. Here are the reported download speeds in Kbps: New York, 18,946; Washington, 15,821; Atlanta, 11,257; Chicago, 10,042; San Francisco, 4,230. What is going on? I know my father is not paying for a 10+ Mbps connection. Is Comcast giving priority to popular speed-test sites?

Ok... and now try with the cache disabled.

Just kidding...

Seriously though, I think he's probably clicked one of those "Click here to make your internet faster" ads... I knew it they work!

Do It Yourself

[Doc Ruby]

The Speakeasy speed tests are indeed easy, and easy to "speak" about on their site with posted ratings. But there's nothing magic about it, that you couldn't do with simple commands from your PC.

All you've got to do is fire up a shell (whether Windows, Linux, or other client OS), and download a big (>10MB) file while timing it. Find an HTML link to a video or something, then download it from the shell (eg. wget or curl in Linux) to a local directory. Watch the minutes and seconds from when you first connect (right after you give the command, after you get the download feedback), to when the file is complete. Then examine (eg. ls on Linux, or use your GUI file manager) the file for its exact size in bytes, then divide the time by the size.

I know this seems obvious, but distrusting Speakeasy's numbers as cooked by Comcast shouldn't be the last act before punting to Slashdot. Real tests, not just examples like Speakeasy, are trivial to run by yourself.

Re:

[tomhudson]

Under linux: time wget "url_of_file_you_want_to_time.iso"

Why do the math when there's a program ready to do it for you?

Re:

[Doc Ruby]

You don't need "time": wget will report the average DL rate when it's done. But since they asked such a basic question, I felt like being pedantic.

Re:

[Solra Bizna]

Unless you've found a server whose bandwidth is lower than yours.

Also, 10MB is not big enough for a reliable test. I'll arbitrarily say 200MB minimum for a fair test.

-:sigma.SB

Initial speed bursts

[DreadfulGrape]

I have Comcast 8 MB/sec. service. When I begin a long, bandwidth-intensive operation my throughput will start out in the low teens, like 13 or 14 MB/sec. Then in about five seconds it will throttle back to just under 8 MB.

Perhaps something like this accounts for the Speakeasy.net results.

Lots of factors...

[SuperBanana]

To name a few:

• Router/signal compatibility. Comcast has switched signals several times and in two cases, it caused horrendous performance. There's also a particular cablemodem (has a big blue "sleep" button on top) that has serious problems with high packet rates and connections (ie, BitTorrent crashes it.)
• Interference.
• Local loop, backbone, and uplink utilization. Guess what, guys? Sometimes traffic peaks for strange reasons. Sometimes it's a virus outbreak, a new movie trailer, or a big news story.
• THE INTERNET . It's unreliable, not guaranteed, never has been, and YOU ALL KNOW THIS AND HAVE BEEN TOLD IT OVER AND OVER AND OVER. I work for a university. We have seriously fat pipes. We have a 10Gbit backbone. And some sites I can FTP from at 2MB/sec. Others, I get 40KB/sec. "Speed tester" services compete for bandwidth just like everyone else. Stop holding them up as some pure, holy source of internet traffic that magically flows through every router at maximum speed.
• Some content is akamai-zed. I get Apple's software updates at maximum line speed, for example.

If you're not happy with your service, CALL THEM. My parents were some of the first people to get MediaOne service back around '98-'99, and every time they had problems, we picked up the phone, and it was taken care of.

I've had the same experience elsewhere. Any time I have problem with the service, be it regular disconnects or lousy performance- I pick up the phone, and a few minutes later someone is checking into signal to noise ratios and such. If you lease the modem, they're usually happy to try sending out a tech and swapping out a modem if you're polite but clear there's a problem. They're usually even more amenable if you pick up the modem yourself at a "service center."

In my years as a customer and having friends who were customers, I've seen a)flooded junction boxes b)in-house distribution amps turned up too high c)1 failed modem d)one buggy model e)several incompatible modems after "upgrades" to the area network (usually to support faster speeds.)

In short: call comcast, ask them to look into it. They've almost always been helpful, through all the various company changes: MediaOne, RoadRunner, etc.

Re:

[pokerdad]

In short: call comcast, ask them to look into it. They've almost always been helpful, through all the various company changes: MediaOne, RoadRunner, etc.

As someone who used to work for Comcast allow me to say rotflmao. Either you are one lucky sob or you are lying.

Just as a matter of example (one among many) during the entire nine months I worked for Comcast the entire state of Illinois never left the outage board. That isn't to say that no one in Illinois ever had a connection, but many people had little or no connection and we were under instruction to do absolutely nothing for anyone from Illinois - just keep BSing them till they gave up.

Some more info

[JimDaGeek]

Testing locations closer to Philadelphia gives the highest speeds. However, other locations seem to vary greatly. For the curious, my father pays $45 a month for his cable modem broadband.

Using the speedtest.net [speedtest.net] site that was posted above, I am getting all kinds of different results.

Toronto: 2,790 kbps down, 1,216 kbps up<br>
San Jose, CA: 2,101 kbps down, 470 kbps up, 92 ms ping<br>
New York: 17,410 kbps down, 1,357 kbps up, 12 ms ping<br>
Tucson, AZ: 4,258 kbps down, 1,461 kbps up,

Re:

[Mezoth]

The higher your latency to a site (aka, how long does it actually take a packet to get there) the slower your bandwidth will be without some extensive TCP window tuning. Reference:

http://en.wikipedia.org/wiki/TCP_Tuning [wikipedia.org]

That is why you get slower speeds the farther out you go, even assuming every link in between is not congested.

Also, most of what you post there is explained by powerboost - very fast downloads for the first few seconds, then they throttle it back. If you ran a sustained download (g

Re:

[JimDaGeek]

Yeah, I know about latency and all that. I just never noticed it as erratic as I have here on Comcast's network. Before today I have never heard of the powerboost thingy. Seems a little gimicky to me.

20 Meg Cable Modems Practical Since 1999.

[Dave Burstein]

19 megabits on an unloaded cable modem node is quite practical, especially for brief speed tests.The U.S. cable modem architecture is based around nodes that share 35 megabits or so downstream. RCN even sells a 20 megabit service, which David Reed buys and reports gives him the promised 20 megabits most of the time. In practice, most nodes run with 5-10 megabits typical load, as only a fraction of the time multiple users on one node simultaneously download megabits and fill the pipe. Statistical multiplexing (sharing) works much better than people expect on cable modem networks, especially on well managed nets that split nodes and otherwise expand capacity when needed because a node gets frequently congested.

Comcast and cable suppliers are working on several techniques to allow customers to get more than the 6 or 8 meg typically allocated, while not causing undue congestion. "Speed burst" technology tests the network load, and if uncongested temporarily raises the speed of an individual modem making a fast download for a brief period. While that's marketed as "doubling" speeds to 12 and 16 megabits, bursts to 20 and 25 megabits are also practical.

The new technologies require upgraded equipment and are typically being tested first and then rolled out market by market. So it would be no surprise if a subscriber in Philadelphia (Comcast's home town) is benefiting from a test or early deployment of faster speeds than Comcast customers elsewhere.

100 megabit+ (shared) cable modems are being deployed in Japan, Quebec, and France, bonding 3 or 4 35 megabit channels for higher speeds. These are early "DOCSIS 3.0" products, unlikely to be widely deployed in the U.S. until 2009. Comcast's CEO, Brian Roberts, demonstrated 100 megabits at the cable show in Las Vegas this spring, and will probably test widely in 2008 and go into deployment (especially where Verizon is building FIOS) the following year. DOCSIS 3.0 requires a new cable modem unit, however, so this customer is unlikely to be an early tester.

That doesn't explain why the test to San Francisco only ran at 4 megabits, which could be explained by node congestion a few minutes later, inferior Comcast backbone connections to Speakeasy's host in San Francisco, or other circumstances. For more details on coming faster cable modems, google DOCSIS 3.0.

Dave Burstein

Editor, DSL Prime

They are up to it.

[WindBourne]

I tested my comcast 6 MB with and got 1.2 MB., but With speakeasy, it ranges from 8-12 download. It is obvious that they are selectively caching. [bandwidthplace.com]

Re:

[Technician]

Maybe not.

I tested my comcast 6 MB with and got 1.2 MB., but With speakeasy, it ranges from 8-12 download. It is obvious that they are selectively caching. [bandwidthplace.com]

Who are you connecting to? For a while, I had a 60 Meg connection at work. DSL speed tests witht the graph bar were fun to print out an post. With a speedy connection at work, I could easly find ISP's and webhosts with serious connection problems. Many things pop up like they are on my local hard drive. Other things load like dia

The results are erratic

[Dracos]

I did several consecutive speed tests last year (I'm on Comcast in Sacramento), and the results were erratic at best.

Over the course of about an hour, 20 tests said my bandwidth ranged between 3Mbps and 24Mbps (all to the same server, average was about 9Mbps), and I pay for 8Mbps.

In a word, it's Comcastic!

Adelphia to Comtrash

[BanjoBob]

When Comtrash acquired Adelphia, my net speed dropped from 6 Mbps to 1 Mbps. I called them repeatedly and they came to the house repeatedly to test. Yep, 1 Mbps was all I could get. But, with Adelphia, it was a reliable 6 Mbps. Finally a service rep said that most people don't know how to test their connections and that Comtrash was reserving the bandwidth for their new VoIP and telephony products. So, I dropped my $60 per month 1 Mbps and with with a $30 per month 1.5 Mbps. I got 50% more for half th

LanSpeed

[BanjoBob]

There is a nice little freeware program called LanSpeed by OrcaWare. I don't know how reliable the numbers are but its fun to watch your uploads and downloads.

I remember that when I had Comcast, my network traffic was pretty constant -- even if I wasn't doing anything! When I switched to a DSL line, that all stopped. I never did figure out what all the Comcast traffic was about.

Anyway, you can find LanSpeed at
http://members.chello.nl/~m.vanosta/orcasoft/index .htm [chello.nl] It is a fun little utility but, ag

Comcast is fast...

[Newer Guy]

My brother (who is in the Boston area) has their standard service. He's been getting 15,000/3000 Internet for quite some time now. It even bursts to almost 30,000. he's getting amazingly fast speeds. I saw download speeds on his computer well in excess of 2 mB/sec. I wish I had those speeds here in L.A. with Road Runner. On a good day I get 9600/960 and I have their extreme service (which costs an extra 10 dollars a month).

amazing

[Dahamma]

The post is basically about how Comcast, against all previous expectations based on their crappy service, has actually provided MORE than promised? And that makes it time to bash them again?

Hey, I can't stand Comcast as much as the next poor customer (probably more, since I used to work at @Home, which was killed by these damn cable companies) but give be a break, they have actually done something that benefits the average customer (give them huge initial download bandwidth to make web browsing FAST, but e

SuddenLink

[MrCopilot]

Rural KY, I have only two options. SuddenLink and DSL. 3mb/s or 1.5. I chose 3. Only I recieved 1Mbs. I use linux and knemo gives me a steady stream of data as to throughput and I have NEVER got even close to 75% of my advertised 3mb, Complaints to Suddenlink and Hours on the telephone has led me to the conclusion that I should have gone DSL. They have since "upped my speed to 3mbs but I havent noticed it. Average DL speed is a pretty constant 31kb/s Less than Dial up for $DIETY sake. This is why I pay for

Value Propositions

[IBitOBear]

Comcast has no real interest in preventing faster _download_ speeds than what is advertised if there is no line contention. It would cost more than it was worth to truely throttle data going from them to you. They _do_ have a real interest in throttling their upload speed. Consequently on a really idle link there is no real reason _not_ keep the customer-directed data bandwidth full.

In quality of service terms, you put allocations in the QOS table but you let lower tiers "borrow" from higher tiers when t

Re:

[GizmoToy]

That's a great transfer rate. Do you happen to know what they're charging for that speed in Philadelphia? Nothing affordable even comes close around here.

Re:

[JimDaGeek]

The 2.6.22 patch came down at around 5.5 Mbps. Which is weird, because the speed test sites have generally been accurate from my TW cable account down south. However, the speed test here still shows 12+ Mbps, though as I pointed out, big downloads are at or near the 6 Mbps mark.

Re:

[pyrrhonist]

If you call and complain at night that you're getting less than promised speeds, they can up you.

Steeb upped his speed, so up yours!

sounds like channel allocation

[r00t]

Cable modems are strongly based on TV channels. There are separate channels for upload and download. Normally, you share a channel with other people. An upload channel is time sliced; everybody gets a turn to transmit. (like GSM phones) A download channel shoves packets for everybody, a bit like switched ethernet.

There are extra channels. When you have a really big download, the cable system will give you exclusive use of one of these extra channels if there is one available. You thus get really high speed.