Need help understanding bandwidth and such!

[ChrisVadeboncoeur]

Hi! I'm pretty use to the computer part deal, but what happen between that lan port (or wireless) and the router is still mystery to me!

 

So... my ISP give me 120mbps.

Let's say I have an AC1200 typical 2-band router. (Normally advertised as 300+867mbps or whatever)

So by that I think "ok 2.4 can transfer (or speak let's say) with my device at 300mbps", "and 5 can transfer (or speak with my device) at 867mbps"

 

(I'm already aware of the 2.4 vs 5 range difference)

 

Here are my question:

1: If I have 2 device connected to the 300mbps 2.4 band, do they each get 150mbps access at the same time or will they go turn by turn or some other deal. And so with the 5 band will 2, 3, 4 etc devices split the 867mbps?

 

2:  following that question, even if one device can send a message from itself to the router at let's say 300mbps on the 2.4 band, it can only "exit" my household and transfer throught the internet at 120mbps because of my ISP?

 

3: I found mixed answer about this one, does a wired connection affect the wireless network? If so in what way? Does it affect bandwidth? Does it share a part of the ISP speed (ex. 50mbps for LAN and 70mbps for wireless?)

 

Thank you so much in advance! 

 

[Giiman95]

@ChrisVadeboncoeur

1. It boils down to a couple factors. Distance from your router, interference from nearby 2.4 devices and number of devices connected. 300mbs is a theoretical speed. You will be hard pressed to ever see that. It's not an even split of bandwith because certain traffic takes up more proccessing resrouces, thereby taking away from other devices. It really will depend on the three variables I mentioned.

 

2. Correct. Any outbound/inbound traffic will be limited by the speed provided by your ISP.

 

3. Your router sends each packet one at a time. That means that the speed your router can do that will affect you more than the speed of the ISP.

[mynameisjuan]

28 minutes ago, ChrisVadeboncoeur said:

1: If I have 2 device connected to the 300mbps 2.4 band, do they each get 150mbps access at the same time or will they go turn by turn or some other deal. And so with the 5 band will 2, 3, 4 etc devices split the 867mbps?

With wireless there are timeslots on when a device is allow to speak. If a time slot is open because no one else is talking you get full rein. So 2 devices connected and one is passing 0 traffic, the other can pull full bandwidth. If at any time other devices talk bandwidth is cut down. 

 

This is why if a single device has a weak signal and packets keep failing the router keeps retransmitting (aka stealing other slots) and other devices have to waiting. 

 

28 minutes ago, ChrisVadeboncoeur said:

2:  following that question, even if one device can send a message from itself to the router at let's say 300mbps on the 2.4 band, it can only "exit" my household and transfer throught the internet at 120mbps because of my ISP?

Correct. This is what people get confused when their LAN ethernet ports says 1000GBps!!! but they cannot go past 60mbps. 

 

But note this is a good thing because now more devices have room for retransmission (as noted above) before an impact begins to be noticeable.

 

28 minutes ago, ChrisVadeboncoeur said:

3: I found mixed answer about this one, does a wired connection affect the wireless network? If so in what way? Does it affect bandwidth? Does it share a part of the ISP speed (ex. 50mbps for LAN and 70mbps for wireless?)

So to simplify this, thing of wireless as another wireless LAN port. Hence why wireless is call WLAN. You router essential is there to take both LAN and Wireless and pool them together. Its all first come first serve. So for your 120mbps your LAN devices can use 120mbps and so can your wireless. But once one device begins dipping into that bandwidth other devices can only use the remaining. 

 

28 minutes ago, ChrisVadeboncoeur said:

Let's say I have an AC1200 typical 2-band router. (Normally advertised as 300+867mbps or whatever)

Also as a final note, these are THEORETICAL speeds. Wireless has overhead by nature, typical 10-15%. So getting even 200mbps in a perfect situation is perfectly normal. With 5ghz its normal to hit around 500mbps. 

 

Now there are other magical things that you see when a router say 6000MBps!!!! Its essentially adding multiple antennas to a device and they all work at the same time. But device need to have the multiple antennas too (which is rare) so its really only beneficial in cases with 100s of devices.   

 

This is also excluding interference, distance, rogue devices, devices connecting on B/g and so on. Wireless is a beast to fully wrap you head around.

[ChrisVadeboncoeur]

@Giiman95 Thank you very much for your explanation!

[ChrisVadeboncoeur]

@mynameisjuan Wow! Thank you for this detailed answer. This really helped me understand this issue a bit more. but as you said it's still very tricky!