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upload speeds

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Regular Contributor

upload speeds

why does xfinity have such slow upload speeds?  when do they plan to increase them?  

Expert

Re: upload speeds

What speed do you consider as being slow ? Which speed tier do you subscribe to ?


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Regular Contributor

Re: upload speeds

i subscribe to whatever the 150 mbps speed tier is....

 

i don't have an issue with download speeds but upload speeds are my issue with xfinity.  majority of other providers may have slightly slower download speeds but their upload speeds are far superior to xfinity. 

 

i consider any upload speed below 20mbps slow..... if you were to pay the same amount of money to fios or cox you would get way better upload speeds... 

Expert

Re: upload speeds

You could try to upgrade to their gigabit speed tier and get 35 up.



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Regular Contributor

Re: upload speeds

i don't think you have to subscribe to the MAX package to get a decent upload speed... 

Frequent Visitor

Re: upload speeds

This is a complex issue for Internet over cable, but I'll try to give a simple explanation.

 

When the cable head end is sending data to users, the Head end can transmit at the full speed on cable channel, and user modems constantly listen for the data packets addressed to their MAC address, and grab the data intended for that MAC.  The point here is the download cable channel is utilized at 100% of capacity.

 

Upload is totally differnet.  User modems can't just send date when they want to, or collisions between modems makes the data from both modems (or 3, 6, 10 modems) totally unreadable by the cable head end.  There are several algorithums that can be used to miticate this problem but I'll describe just one, known as Aloha.  For upstream, the cable channel is shared with several modems.  To prevent each modem from colliding with other upstream data packets the cable channel is devided into  a  time slots and assigned to each modem.  Because of time gitter from modem to modem, every other time slot is empty, reducing upload capacity to half or less than the download data.  This exact problem exists on satellite Internet.  

 

Nowdays, there are other more efficent upload algorythms are used, but this gives the basic problem.  The 5, 10, and 35 mbits upload is not arbitray but are dictated by the download speed to you are paying for, the higher the speed, higher upload speed is need to handle the acknowledgements back to the head end and leave some bandwidth for some user data of download is maxed out.

 

Expert

Re: upload speeds


@Waqas1 wrote:

i don't think you have to subscribe to the MAX package to get a decent upload speed... 


Earlier you compared FiOS (fiber delivery) to Comcast (DOCSIS coax cable) and you can't. It's like comparing apples and oranges.

The current upstream / return path bandwidth spectrum allocation on DOCSIS is physically limited. It's the nature of the beast.


Here is an informative article about the future for the upstream bandwidth capability for DOCSIS based systems;

http://www.multichannel.com/news/distribution/comcast-eyes-upstream-expansion-it-pulls-fiber-deeper/...

The do offer a 2 gigabit (with symmetrical speeds) FTTH (Fiber To The Home) service in some areas.

 



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Expert

Re: upload speeds


@bvwhitney wrote:

This is a complex issue for Internet over cable, but I'll try to give a simple explanation.

 

When the cable head end is sending data to users, the Head end can transmit at the full speed on cable channel, and user modems constantly listen for the data packets addressed to their MAC address, and grab the data intended for that MAC.  The point here is the download cable channel is utilized at 100% of capacity.

 

Upload is totally differnet.  User modems can't just send date when they want to, or collisions between modems makes the data from both modems (or 3, 6, 10 modems) totally unreadable by the cable head end.  There are several algorithums that can be used to miticate this problem but I'll describe just one, known as Aloha.  For upstream, the cable channel is shared with several modems.  To prevent each modem from colliding with other upstream data packets the cable channel is devided into  a  time slots and assigned to each modem.  Because of time gitter from modem to modem, every other time slot is empty, reducing upload capacity to half or less than the download data.  This exact problem exists on satellite Internet.  

 

Nowdays, there are other more efficent upload algorythms are used, but this gives the basic problem.  The 5, 10, and 35 mbits upload is not arbitray but are dictated by the download speed to you are paying for, the higher the speed, higher upload speed is need to handle the acknowledgements back to the head end and leave some bandwidth for some user data of download is maxed out.

 




 


When Full Duplex DOCSIS comes out, things will change but we are still a bit of time before modems and speedtiers for those standards.

 

 https://www.cablelabs.com/full-duplex-docsis/


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