Originally posted by: Mucman
If you people so desperately want upload capacity, why don't you pay for a co-located server?
Originally posted by: guyver01
Upstream is very limited, depending on what type of modulation is used.
Cable providers currently use an upstream modulation technique called "QPSK," or "quadrature phase shift key." It's the same technique used in direct broadcast satellite transmissions. It's different, slower and sturdier, from the downstream modulation used for digital traffic ("QAM," or quadrature amplitude modulation). QPSK yields a usable capacity (after overhead) of about 1.2 Mbps/MHz. Multiplied by the 25 MHz of usable upstream bandwidth; the aggregate upstream capacity is about 30 megabits per second.
If you provide ... say... 500 Kbps upload to each user.. all it takes is about 50-60 users to SATURATE your upstream, and that affects downstream (TCP/IP requires an upstream ACK packet to be sent for each downstream packet... saturate the upstream, and that ACK isn't going thru). When a cable company usually is trying to get 300-500+ subscribers per connection online, you need to determine an optimal setting vs cost of splitting the areas.
Originally posted by: Entity
Good answer, guyver01.![]()
Better than communism.Originally posted by: fivespeed5
Originally posted by: Mucman
If you people so desperately want upload capacity, why don't you pay for a co-located server?
??? you'd have to get the files on that server some how right? what if I wanted to send something from my home pc?
reading all the responses I think dmcowen674 is the winnAr! In the end it's always about money I suppose.
Originally posted by: Nocturnal
So you don't run a server of porn, warez, etc.
Originally posted by: guyver01
Upstream is very limited, depending on what type of modulation is used.
Cable providers currently use an upstream modulation technique called "QPSK," or "quadrature phase shift key." It's the same technique used in direct broadcast satellite transmissions. It's different, slower and sturdier, from the downstream modulation used for digital traffic ("QAM," or quadrature amplitude modulation). QPSK yields a usable capacity (after overhead) of about 1.2 Mbps/MHz. Multiplied by the 25 MHz of usable upstream bandwidth; the aggregate upstream capacity is about 30 megabits per second.
If you provide ... say... 500 Kbps upload to each user.. all it takes is about 50-60 users to SATURATE your upstream, and that affects downstream (TCP/IP requires an upstream ACK packet to be sent for each downstream packet... saturate the upstream, and that ACK isn't going thru). When a cable company usually is trying to get 300-500+ subscribers per connection online, you need to determine an optimal setting vs cost of splitting the areas.
