The difference between Fiber and Cable lines (speed)?

[willbeokay73]

A competition ISP sent marketing folks to my neighborhood who state that they have recently installed dedicated fiber optic lines.

According to them, the line is basically immune to slow down from traffic (from heavy usage time etc.), and that I would notice increase and consistency in internet speed.

They claim that 20mbps of fiber speed is faster than the 50-60mbps offered by the cable line ISP, and that their fiber line megabit per second value is 8-10 times greater than that of the cable line.

The marketer believes that their 20mbps speed would equal around 200mbps speed on the cable line.

Do these claims hold any weight? Why do they market with 20mbps sticker if they're so confident of the fiber's overall superiority to that of the cable lines?

Does that mean that when I run speedtest with the fiber line, the speed would show up as 20mbps but somehow it will rival the speed of 200mbps on cable line? Could there be a significant difference in ping speed and does it matter? What am I missing here?

 

[pm4]

To be polite . That is nonsense.

Mbit/s is same no matter what medium you use to transfer information. Optic lines got potential for higher Mbit/s overall BUT if they provide you with 20 Mbit/s on optic it will be same speed as 20 Mbit/s on other mediums.

Other thing may be latency or stability, but that is dependant on so many things that just optic vs other medium won't be only/main issue for it.

So in short they are lying and big time.

 

[bill001g]

It really depends how they have their fiber implement and how over subscribed the cable system is. What they are referring to is that the fiber connection between your house and whatever they connect to is dedicated bandwidth so between your house and this common location you can get a certain bandwidth that only you can use. Beyond this point you don't know it is likely oversubscribed just like other systems. Cable the 200m or whatever is shared bandwidth between you and all the neighbors on the same cable. Your modem actually receives all the data for all your neighbors and you all mixed together and it just extracts your data. This is why a couple of guys running torrent any place near you can degrade every ones connection.

It all comes down to over subscription rates and where they occur.

 

[willbeokay73]

See if I understand correctly- when they say fiber of 20mbps, it is just that- a flat 20mbps. They may have higher tolerance to shared traffic affecting the overall speed of the internet, but beyond that, there's no difference between 20mbps of cable line and 20mbps fiber line when they are at the speed.

So I can safely assume that their statement of 1mbps on fiber = 5-10 mbps on cable, and the idea that somehow 20mbps on their fiber line would equal the speed of 200mbps on the cable line is false?

 

[pm4]

Yes it's false.
And no about shared traffic it does not have any benefit unless you would have really dedicated fiber cable only for you up to point where your ISP connect to rest of internet which i doubt anyone have as it would he crazy expensive.
Normally ISP use bigger cables which are made of lot of smaller ones. For example each small cable can have bandwidth 1Gbit/s and you got 10 of those for total of 10Gbit/s. And they split those cables to even smaller which can hold for example 100Mbit/s and you get one of those to your home to ONT and from there through normal ethernet cable to your router. (numbers i used are not real just random to illustrate my point).
But they can still control your max speed on hardware level thx to few clever and expensive switch boards which can often limit it on per end point base. It's not exact as you sometimes get speed little faster than is your promised limit and sometimes little slower.
Exactly same situation (just different technical solutions) is on classic older networks so there is no benefir for fiber network there. It's called aggregation (that is what bill001g mentioned) In short if you got fiber cable (it's same for any type of connection) it got certain finite max bandwidth (speed). For example 1 Gbit/s now if you would have 10 clients and promise 10Mbit/s to each it would be total 100Mbit/s so np on that one fiber cable. But if you would promise same to 100 clients it would already saturate that cable.
In reality ISP often put more people on same link so they get over max limit. It's way for them to make it cheaper because they assume (and they are right in that) that not all will use their bandwidth at max speed whole time. So for example for that 1 Gbit/s they could put 150 clients each with 10Mbit/s. But if 100 of those people would use it 24/7 they would degrade speed for rest because of it, as there would not be enough bandwidth for all to use at 10Mbit/s. Mostlikely everyone would have lower speed.
Ofc that promised speed is theoretical. It also depends on where you are connecting to, current traffic or possible problems on internet and so on ...

 

[bill001g]

To get actually answer would require very detailed comparisons of how they implement both systems. It greatly depends how the ISP implements their network. It really isn't the technology that makes the difference it is the ISP policy of over subscription.

Lets say all the servers you ever wanted to use were in some data center directly hooked to the ISP somewhere close to your house and you were sharing the data center with 200 neighbors. In this case fiber you would be guaranteed 20m minimum and maximum to this data center. On cable there is no guarantee but you could if you were very lucky get 200m and very unlucky get say 1m. Now if instead of a data center you have 200m connection from the neighborhood back to the central location. In this case if you were very unlucky you would get say 1m on both systems but if you are lucky you would be constrained to 20m on the fiber but could go to 200m on the cable.

What you see in actuality is cable tends to be faster because the ISP do not actually over commit as much as they did in the past. It really depends on how many high traffic users happen to live very near you. If you have a lot then fiber you know you will always get your 20m. If you have very few then you likely could get more than 20m off the cable.