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Why are upload speeds so much slower then download speeds

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  • Download
  • Internet Service Providers
  • Networking
Last response: in Networking
June 1, 2011 10:05:08 PM

I was wondering why are upload speeds so much slower then download speeds with residential IPS. I know downloading is alot more common then uploading something.
Does it cost more or something, for the ISP to send information out.

More about : upload speeds slower download speeds

June 1, 2011 10:19:09 PM

My guess would be to discourage sharing files. No idea really though.
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June 5, 2011 4:47:43 AM

Yeah it was an interesting read.
I hope they get the upload speeds faster, I have a VPN in to my house and it does get slow. But handy when you leave a file home that you need.
We use virtual machines for work, and if you forget on of those and go on a business trip, you are look at a long download time to get your 7GB+ virtual machine.
January 22, 2013 8:54:48 PM

Personally, I think it's to conserve backplane bandwidth on the ISP's core routers and switches. The backplane of a switch or a router is the maximum amount of data that can traverse the switch at once. So say a 48 port switch has a backplane speed of 8.8 Gbps (gigabits per second). That switch can theoretically 'switch' (pass, or allow through) 8.8 Gbps of data at one time. My assumption is that, under the guise that the ISP is preventing illegal file sharing, they are really stretching their equipment further to make more money off their customers while investing less in their infrastructure. If I'm right, it explains why our internet speeds are so much slower than other countries. This doesn't explain, however, why we pay more for internet service than other countries.
January 23, 2013 6:38:54 PM

The original reason, which is still valid for most subscribers, is a physical limitation of bandwidth.

For example, with DSL or Cable your connection uses a single wire (yes, DSL actually uses two wires, but they are unshielded and closely coupled so they act like one) to handle download and upload, and depending on the quality of the connection and distance it can handle a maximum number of total bits per second.

So, if you have a DSL connection with a max bandwidth of 2Mbps you can either split that 1Mbps down and up, or more commonly 1.5Mbps down and 384Kbps up. Most people would rather have the 1.5 down.
September 5, 2014 3:18:43 PM

I have worked as a Sr. Network Engineer for around 15 years now. I can add my viewpoint and tell you it perplexes me a great deal to see that these internet providers are not working to keep their customers at the best possible speeds. In most (probably all) cases it's not even a matter of having to keep their equipment current. Certainly not to give customers a symmetrical upload and download speed. To bring the old 56k modem days into it just clouds the issue. We have advanced WELL beyond those days. But even during those days, none of us had 56k download and 1k uploads. It was always 56k by 56k right? When we moved to ISDN, I had 128k down (with 2 B channels and 1 D channel -- remember guys?) and 128k up. If anything, it might have had to do with a device called a DSLAM. (At least in the DSL days) A Digital Subscriber Line Access Multiplier. And that's just a guess. Multiplexers could always be a little hinky and I could see it getting hung up with acknowledgments. In fact, see RFC5690 and see if anyone can make sense of it. But this occurs even with Fiber.

Maybe we should look at it from a different direction. At home I have 1.5 Mbps upload and 27 Megabit downloads. Maybe some ISP's only give you enough upload speed so that you can send enough acknowledgements for the size of your download speeds. In other words, I can't have 27 Megabit downloads with a 56k upload speed. It would never be able to acknowledge the packets it has received, thus tons of retransmissions. So what is the ISP's problem? Are you afraid we'll start running servers at home? We already do!

Bottom line is, there is no good reason for an ISP to slow down an upload speed. There's got to be an ulterior motive here:

Is it:
A.) The ISP wants to stop or discourage file sharing.
B.) The ISP wants to discourage running home-based servers.
C.) All of the above.

Sorry for the long thread... But I think I just stumbled onto the answer.... At least this would make the most sense to me:

This might just be some sort of weird overlap within a company. When Verizon launched FIOS, I want to say that FIOS was a whole new business unit for Verizon. AT&T likely just ported a lot of its infrastructure over from the DSL side of the business. So it might be that Verizon FIOS started fresh, not having to deal with legacy policies, legal issues, boilerplate contracts, etc. and AT&T did. It might have made sense somehow in the DSL world, like I described above with the DSLAM, for AT&T to keep the speeds non-symmetrical, but Verizon didn't have that issue in the fiber world. Maybe AT&T just needs to update a little bit and get with the times. non-symmetrical circuits are nonsensical. I want to think that AT&T wants to give their customers what they want, but they might just be a little out of touch with their customer base. Maybe when Google Fiber comes to town, they'll ask the question, "Where'd everyone go?"
September 5, 2014 3:26:53 PM

And Verizon FiOS is in the process of changing everyone's speed to be symmetrical. A previous 50/25 converts to a 50/50. Zero change in price.
Mine changed a couple weeks ago. And in actual fact, the upload is higher than the download.

September 10, 2014 4:58:35 AM

It's interesting to hear that the ISP can adjust this up/down balance, rather than it necessarily being a hardware issue. I have just logged a call with my ISP because my (rural) broadband had about 3.5 down and only 0.19 up (about 5.5%), and Google Hangouts and other video conferencing is a nightmare.

I suspect that it's for advertising reasons. Everyone quotes their best download speed -- none of the ads quote any upload speed, or even that it exists and why it might be important. My guess is that someone plucked a value of of thin-air (say 5%) that would be acceptable to most folks on the basis that they can quote a higher download speed.
September 10, 2014 7:14:42 AM

I agree I think it is a policy issue rather then a hardware issue. Some other reason might be because I have "home internet" and not "business Internet". Business internet almost always has an equal or half ratio on upload speed from my experience.

One other reason I thought, upload is so slow, is Mal ware and bonnets. If upload and download were equal it would be very easy to find 20 vulnerable computers with 50megs upload. You could completely kill a few targets with a gig connection with that.

But I think this excuse is null now, because of all of the VPS out there people can hack, that have a lot faster connection then 50 mbps.

With more people then ever wanting to upload stuff I would hope this pushes ISPs to change this policy. I am caped at 200GB a month up and down so it isn't like I can go on a crazy uploading spree.
September 10, 2014 8:47:57 AM

If you get a home plan, it's not designed to be used for uploading that is not very "home use". The regular use plans are for those that use the web to get info, sream to the computer not from it. The business plans are the ones that often offer a higher upload speed but of course you will be paying more for that service.

The ISPs would not want to clog up their available bandwidth with everyone running streaming movies from their houses unless they are paying for it.
September 10, 2014 10:59:02 AM

Catsrules: I don't think it has anything to do with malware or bots. Most of those are very VERY small in size. Even a 128k connection would be more than enough to spread that quite easily. And when it comes to flooding or DOS attacks, these days you have malware that can create hordes of zombie computers waiting on a command to commit what little (or great) resources they have to flood out a target of the commanders choosing.

Hang-The-9: I think you could have a point on the possible streaming problem though, aside from Slingbox, which I'm not even sure is being sold anymore, that's really not been a concern that I've seen or heard about. But I also think that your view of what "home use" entails is a bit dated. We didn't have Facebook years ago to which we're uploading twenty 3MB pictures a day. YouTube to which we're uploading an enormous amount of video. At least 500MB or more for most people that just send up home videos for Aunt Edna to see. Syncing your backups with Carbonite, Google Drive, Dropbox, Evernote or a gaggle of other such services. Not to mention the fact that, if you are trying to watch Netflix or Vudu (or sometimes both at the same time in my house), you can't watch at all whilst uploading a large file... Because there's no room on the egress path for TCP acknowledgements for the downloaded video content. (Does not apply to cablebox type watching. That is all multicast traffic. Not treated the same as streaming services.)

By the way - remember - if you see the spinning wheel of death today on Netflix - it's because today is "Internet Slowdown Day". See: https://www.battleforthenet.com/
Late for a meeting. Sorry for any typos.

Have a great day, y'all. -R
September 12, 2014 5:46:28 AM

Rick Hollmer said:
Catsrules: I don't think it has anything to do with malware or bots. Most of those are very VERY small in size. Even a 128k connection would be more than enough to spread that quite easily. And when it comes to flooding or DOS attacks, these days you have malware that can create hordes of zombie computers waiting on a command to commit what little (or great) resources they have to flood out a target of the commanders choosing.

Hang-The-9: I think you could have a point on the possible streaming problem though, aside from Slingbox, which I'm not even sure is being sold anymore, that's really not been a concern that I've seen or heard about. But I also think that your view of what "home use" entails is a bit dated. We didn't have Facebook years ago to which we're uploading twenty 3MB pictures a day. YouTube to which we're uploading an enormous amount of video. At least 500MB or more for most people that just send up home videos for Aunt Edna to see. Syncing your backups with Carbonite, Google Drive, Dropbox, Evernote or a gaggle of other such services. Not to mention the fact that, if you are trying to watch Netflix or Vudu (or sometimes both at the same time in my house), you can't watch at all whilst uploading a large file... Because there's no room on the egress path for TCP acknowledgements for the downloaded video content. (Does not apply to cablebox type watching. That is all multicast traffic. Not treated the same as streaming services.)

By the way - remember - if you see the spinning wheel of death today on Netflix - it's because today is "Internet Slowdown Day". See: https://www.battleforthenet.com/
Late for a meeting. Sorry for any typos.

Have a great day, y'all. -R


That had nothing to do with my point of view, but how the ISPs setup their plans. You don't need a huge upload pipe to upload pics, just a bit of time. The issue comes when you try to stream HD movies from a home server over the internet. At some point if the IPSs give everyone fast upload speeds they will run into issues unless they upgrade the equipment, which they need to pay for. Business plans factor in the bandwidth they take up as well as the faster support they normally get into the extra cost for those plans.
September 12, 2014 11:03:58 AM

Not trying to be a know-it-all here. This is just my opinion, of course. But I don't think that some ISP's are scaling appropriately. To say that you don't need a bigger pipe, just more time is a little disingenuous I think. Technically you're right, but you could also make the same argument for walking from Dallas to Austin. You don't need a car. Just more time.

Look, my average yearly photograph uploads in 2004 were probably 1/4 of what they were already this year. I don't think anyone can reasonably say that Verizon has a better and newer network than AT&T. So why the disparity in their speed plans? I think it's just something to do with necessity. AT&T doesn't feel it necessary to increase their speeds because AT&T and Verizon apparently have an agreement that they won't work in the same areas. (Isn't that the makings of a monopoly?) Case in point: AT&T recently announced that they will speed up customers with a new service called "GigaPower". Why did they do that in Austin of all markets? Could it possibly be that Google Fiber just rolled in there a few months ago offering faster speeds at a lower price?

Point is, they CAN do it if they feel threatened. Which tells me it's not an infrastructure issue. As an AT&T customer, I'm here to tell you that THE MOMENT Google Fiber is available in my area, I'm going to remember how I was treated as an AT&T customer for the past 4 or 5 years. Not to say I was treated poorly. They have good customer service. But they COULD have offered better speeds and chose not too until they HAD too. And that will play heavily in my decision to either stay or go.

(Do you have a place I can keep this soapbox?)
October 30, 2014 4:16:08 PM

chefwear said:
Personally, I think it's to conserve backplane bandwidth on the ISP's core routers and switches. The backplane of a switch or a router is the maximum amount of data that can traverse the switch at once. So say a 48 port switch has a backplane speed of 8.8 Gbps (gigabits per second). That switch can theoretically 'switch' (pass, or allow through) 8.8 Gbps of data at one time. My assumption is that, under the guise that the ISP is preventing illegal file sharing, they are really stretching their equipment further to make more money off their customers while investing less in their infrastructure.


Nobody doing any serious networking has used backplane routers in like 15 years. These days, routers use a non-blocking switch fabric that can provide line rate forwarding in and out of all ports at the same time. Yes, there is some oversubscription, but nothing like the old backplane days.

Also, even a low-end switch will utilize a 64x10G switching chip to provide non-blocking line rate forwarding to 64 ports.