What exactly are
differences between Cable and DSL Internet services?First let's define our terms.
Bandwidth vs. Latency:
Bandwidth & Throughput Digital bandwidth or throughput is a measurement of
amount of data that can be transferred over a digital line over a specific amount of time.
Latency Latency is
time it takes to deliver a packet of data from one place to another. This includes
time it takes for an electrical or optical signal to travel a certain physical distance (propagation delay) and
time it takes to process these signals along
way (processing delay).
So bandwidth is a measure of frequency or a rate of service delivery while latency is a measure of time or signal delay.
Technology Comparision.
Cable service uses signals transmitted through
same coax cable that cable television uses. DSL uses normal phone lines to send digital signals to a DSL modem.
Coaxial cable has a far greater capacity than RJ-11 phone cable. But,
coaxial cable coming into your home is shared with many people outside your house and provides many services. Cable modems have higher bandwidth though
connection is shared among cable users in your service area and even with your digital cable box. As a result
performance is quite similar to DSL. Generally, cable modems can achieve better peak throughput, but this high bandwidth is not consistant and depends, again, on load, affected by time of day and other factors. DSL service usually provides a more constant, consistant feed, with lower latency. The distance to your exchange or "switch" is
main factor that determines DSL quality of service. Look for
green (in Toronto) phone exchange box in your neighbourhood and note how far your home is from that box.
Service Comparison. One of
advantages of DSL over cable modems is that
line to
exchange or "switch" is not shared. Though ISPs trying to sell DSL services will tout this as a major advantage, slow cable modem speeds have very little to do with this and have much more to do with
fact that cable service is shared among many users and services.