Why is DSL Upload slower than Midband Upload?

drunkmonkey

This puzzles me, can get about .35mb on my eircom lines but can get 1mb+ upload using midband.
Called Eircom and they said that's as quick as it can go.

Any ideas?

Nemeses

Midband (3G Technology) and DSL are two different types of technology. That would explain that. DSL usually works something like 8:1 download / upload ratio (or something close - I cant work out the math right).


To put it simply, it is to save bandwidth. Let's say we have a 1 mbps download and upload connection. Instead of wasting some of the upload bandwidth, since you're not going to use it often, the internet providers can just add 512 kbps to the download bandwidth making it 1.5 mbps download and 512 kbps upload.

Hope that explains that for you.

watty

It's not to "save" bandwidth. The reason is because 3G is primarily intended for Symetrical application of Digital Voice. It can't be changed for Data as that is using the same system.

The RF channel for Download and Upload is same size on 3G. Because voice needs the same data in both directions. In HSPA mode there is infact much less upload capacity than peak download, but since all the channel is shared, unlike DSL, and people Download more than upload, the "upload" spectrum is sort of "wasted", if there are not phone calls, then you get more potential upload speed.

Since people Download more than up load, the 3G/HSPA has often faster upload than download.

DSL is not using the normal phone voice channel.
You can have DSL in SDSL, ADSL or reverse DSL. The line has an overall bandwidth and since it's not shared with anyone and DSL is not for voice, it makes sense to have Asymetric DSL (most of bandwidth alocated for Download, say 3Mbps & 0.128MBps). SDSL, Symetrical DSL, on same line would be about 1.5Mbps down and 1.5Mbps upload. Reverse ADSL would be 0.128 Mbps upload and 3Mbps download.

Actual speeds depend on line length.

Nemeses

watty wrote: »

It's not to "save" bandwidth.

In some cases, yes it is to save bandwidth since DSL use a section of frequency on the line (as the graph link will show / help explain that).ADSL provides more download than upload because generally people download more than they would upload.

http://http://upload.wikimedia.org/wikipedia/commons/thumb/8/87/ADSL_frequency_plan.svg/500px-ADSL_frequency_plan.svg.png

Here's a nice graph to show the DSL bandwidth

Technically, you could change the upload frenquency higher than it is there however you would be sacrificing the download speed then.

watty wrote: »

You can have DSL in SDSL, ADSL or reverse DSL.

I believe there is no such thing as Reverse - DSL did you mean:

RADSL - Rate-Adaptive Digital Subscriber Line

watty

Nemeses wrote: »

In some cases, yes it is to save bandwidth since DSL use a section of frequency on the line

I believe there is no such thing as Reverse - DSL did you mean:

RADSL - Rate-Adaptive Digital Subscriber Line

It's never to save DSL bandwidth. DSL uses as much bandwidth as can work on the phone line.

RADSL = Rate-Adaptive Digital Subscriber Line

Reverse ADSL is ADSL with the upload and download swapped. I've never seen it, but it's in theory possible. 128k down and 3Mbps up. More appropriate for a small web server than users. Since it makes more sense to have fibre or put a server in a Hosting Data Centre, there is no market for Reverese ADSL.
ADSL

Symmetric DSL uses same amount of spectrum (blue and green bits) for upload and download, hence has to be slower. Reverse DSL uses the spectrum the otherway round or in opposite proportion. I don't know which.

It's rarer than SDSL http://en.wikipedia.org/wiki/Symmetric_Digital_Subscriber_Line which isn't commonly available as there is little demand for it unless someone is using a Digital PABX (SIP ) and say up to 10 to 20 simultaneous VOIP calls (upload and download traffic is equal on VOIP).

The difference in upload/download on any DSL system is by design to share out the total amount of spectrum between upload and download, never to save bandwidth or spectrum.

clearz

drunkmonkey wrote: »

http://line25.com/tutorials/how-to-create-a-pure-css-polaroid-photo-gallery

It all comes down to the politics on boards.ie and the dominant voices on here. A few years back when we all had 512Kb DSL it was perfectly ok to call that Broadband, but how dare anyone call 14.4Mb HSPA 'Broadband'. I have UPC at home and also an O2 mobileBB account that I use when away from home. I have never gotten less than about 3Mb. I can understand Edge and other 2.5g technologies being refered to as midband but the fact is that 3G and later technologies are Broadband. I think a lot of the backlash against mobile broadband on here has more to do with the low caps than anything else, which is ironic in the fact that Eircoms 'Next Gen Broadband' qualifies as what is known as midband around here.

barnicles

clearz wrote: »

It all comes down to the politics on boards.ie and the dominant voices on here. A few years back when we all had 512Kb DSL it was perfectly ok to call that Broadband, but how dare anyone call 14.4Mb HSPA 'Broadband'. I have UPC at home and also an O2 mobileBB account that I use when away from home. I have never gotten less than about 3Mb. I can understand Edge and other 2.5g technologies being refered to as midband but the fact is that 3G and later technologies are Broadband. I think a lot of the backlash against mobile broadband on here has more to do with the low caps than anything else, which is ironic in the fact that Eircoms 'Next Gen Broadband' qualifies as what is known as midband around here.

Any type of 3G technology is not broadband, it's midband, and it's meant for mobile use, not domestic use. The latency is varied, and you're never guaranteed decent speeds or even a connection. It's not broadband and never will be.

watty

clearz wrote: »

... but how dare anyone call 14.4Mb HSPA 'Broadband'. I have UPC at home and also an O2 mobileBB account that I use when away from home. I have never gotten less than about 3Mb. I can understand Edge and other 2.5g technologies being refered to as midband but the fact is that 3G and later technologies are Broadband. I think a lot of the backlash against mobile broadband on here has more to do with the low caps than anything else, which is ironic in the fact that Eircoms 'Next Gen Broadband' qualifies as what is known as midband around here.

There is Zero Guarantee that HSPA will connect at all. Broadband is always on.

The 14.4Mbps is peak speed near mast with only one user. Speed is shared. With 20 simultaneous connections you would have less than 0.36Mbps if everyone was close to mast. More likely disconnects for 1/4 of users and 0.12Mbps or less.

You simply are not sharing you mast sector with much.

See http://www.techtir.ie/comms/mobile-vs-fixed
and http://www.techtir.ie/forums/internet-faq

1Mbps DSL is Broadband, just about, no form of HSPA will ever be Broadband.

Eircom
Eircom's 'Next Gen Broadband' is mostly 12 year old last generation. I agree that eircom's product is mis-sold and not "NGN" or "NGB". However Mobile is even more mis-sold.
Fibre to Cabinet/Kerb or Home/Premises with an actual minimum of 20Mbps (not up to) and potentially 100Mbps to 1000Mbps is "Next Generation Broadband". But Eircom's DSL is Broadband.