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Question of the Day: Will you be subscribing to the new Disney+ R49 streaming package?
Are all FTTH options we currently get in SA full-duplex?
- Thread starter Reaver.ZA
- Start date
Randy_The_Squirrel
Banned
Apparently not, I remember someone saying the line was asymmetrical.
savage
Expert Member
FTTx (PON) is asymmetrical, whilst Active Ethernet is fully symmetrical.
It's still up to the SP to choose whether or not to provide symmetrical speeds or not though.
It's still up to the SP to choose whether or not to provide symmetrical speeds or not though.
Chevron
Serial breaker of phones
Yes.
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connection symmetry != mode of operation
Basically want to know if you can upload and download at full rated speeds at the same time on current FTTH packages from ISPs
lol see you changed your no to a yes. care to elaborate? or is this just a known fact?
would think this feature would be promoted a lot more by ISPs
Randy_The_Squirrel
Banned
Thanx for the info... also wondered about that
Chevron
Serial breaker of phones
You can easily see this when people do torrents. Upload and download maxed.
My question is, why would you assume this wouldn't be the case?
NulgathNuggat
Member
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Because of Profit and Greed... No
savage
Expert Member
That doesn't mean a service is symmetrical. ADSL / Wireless / PON is asymmetrical, it can not transmit and receive data at the same time. It doesn't not mean it's not suddenly symmetrical because you can achieve the same upload/download speeds
You can run ADSL at 1Mbps Down, 1Mbps Up - it doesn't make it symmetrical. Wireless can also up/down at the same rates, it does not make it symmetrical either. PON won't ever be symmetrical as only one ONT can transmit to the OLT at the same time.
Just FYI.
Chevron
Serial breaker of phones
That doesn't mean a service is symmetrical. ADSL / Wireless / PON is asymmetrical, it can not transmit and receive data at the same time. It doesn't not mean it's not suddenly symmetrical because you can achieve the same upload/download speeds
You can run ADSL at 1Mbps Down, 1Mbps Up - it doesn't make it symmetrical. Wireless can also up/down at the same rates, it does not make it symmetrical either. PON won't ever be symmetrical as only one ONT can transmit to the OLT at the same time.
Just FYI.
Sigh when people don't understand.
OBVIOUSLY I was talking about in relation to advertised rates. Gebus.
Chevron
Serial breaker of phones
That doesn't mean a service is symmetrical. ADSL / Wireless / PON is asymmetrical, it can not transmit and receive data at the same time. It doesn't not mean it's not suddenly symmetrical because you can achieve the same upload/download speeds
You can run ADSL at 1Mbps Down, 1Mbps Up - it doesn't make it symmetrical. Wireless can also up/down at the same rates, it does not make it symmetrical either. PON won't ever be symmetrical as only one ONT can transmit to the OLT at the same time.
Just FYI.
And to add you're wrong there too.
You need to separate the users connection, from the underlying technology.
If I have a 20Mb/s Fibre connection at home because I can't afford a 100Mb/s connection, that doesn't mean I have a 100Mb/s connection. It means I have a 20Mb/s connection.
So even using your example, if I bought a speed limited account from an ISP that limited my uploads and downloads to 1Mb/s, my connection would be symmetrical, even though the underlying technology, ADSL(obviously as that what the A stands for) isn't.
TL
R, the users connection and the theoretical capabilities of the technology used to provide that connection aren't the same thing.
My Openserve fibre is 100 down and 50 up. 100 up would be very nice indeed, but so few cloud storage services upload at 40+Mbps I guess it's not worth caring about.
You seem to know things about fibre. Out of interest, do you know what the max speed that Openserve's FTTH network should be good for? Per household of course.
You seem to know things about fibre. Out of interest, do you know what the max speed that Openserve's FTTH network should be good for? Per household of course.
savage
Expert Member
shrugs...
If a TECHNOLOGY is asymmetrical (i.e. ADSL, Wireless, PON, etc) it is technically, INCAPABLE of transmitting, and receiving a frame at the same time (same exact point in time). Therefore a SERVICE on a asymmetrical TECHNOLOGY, CAN NOT be symmetrical. The underlying TECHNOLOGY does not have the CAPABILITY to transmit and receive frames at the same time.
With with a 20/20 Fiber service, you will more than likely max out tx and rx at 20mbps. The TECHNOLOGY still will NOT transmit and receive frames at PRECISELY the same time (i.e. what a SYMMETRICAL service is), and therefore remains ASYMMETRICAL, or half-duplex...
Are are however able to sustain 20/20 combined on the SERVICE because the TECHNOLOGY is capable of transmitting and receiving frames fast enough, so that it does not slow down the speeds. Not the case in Wireless for example, and not the case in DSL most times either. Won't be the case when PON networks starts getting congested either.
Go put the duplex settings of your network card on your PC in 100/half and go copy some files... You'll see precisely what I mean when you test it at different speeds.
If a TECHNOLOGY is asymmetrical (i.e. ADSL, Wireless, PON, etc) it is technically, INCAPABLE of transmitting, and receiving a frame at the same time (same exact point in time). Therefore a SERVICE on a asymmetrical TECHNOLOGY, CAN NOT be symmetrical. The underlying TECHNOLOGY does not have the CAPABILITY to transmit and receive frames at the same time.
With with a 20/20 Fiber service, you will more than likely max out tx and rx at 20mbps. The TECHNOLOGY still will NOT transmit and receive frames at PRECISELY the same time (i.e. what a SYMMETRICAL service is), and therefore remains ASYMMETRICAL, or half-duplex...
Are are however able to sustain 20/20 combined on the SERVICE because the TECHNOLOGY is capable of transmitting and receiving frames fast enough, so that it does not slow down the speeds. Not the case in Wireless for example, and not the case in DSL most times either. Won't be the case when PON networks starts getting congested either.
Go put the duplex settings of your network card on your PC in 100/half and go copy some files... You'll see precisely what I mean when you test it at different speeds.
savage
Expert Member
Depends on the type of OLTs (or bandwidth of the OLTs) and the amount of splitters in the network. It uses time and wavelength division multiplexing (TWDM) and the bandwidth (TX from the OLT towards the ONT i.e. download, and more specifically RX on the ONT towards the OLT i.e. uploads). The OLT interface has a fixed amount of bandwidth (frequency) that is split between all ONTs through passive splitters. How more splitters in the network, and how more ONTs connected to those splitters, how slower the network becomes as each ONT receives equal time to "talk" on the passive optical network through the bunch of splitters.
Installed my first outdoor fiber in the ground almost 20 years ago already in a private estate. I've been around the block a few times yes. And yes, I'm all against passive fiber networks (due to their inflexibility) and are all for active fiber networks because of everything that active fiber networks offer than PON can't (including open Ethernet standards).
Chevron
Serial breaker of phones
Well I must say I learned something today.
So you can actually get symmetrical, half duplex, connections, and asymmetrical full duplex connections. They are independent of each other. So my example of a speed limited 1/1 adsl connection would be symmetrical, but half duplex.
So that's where you went wrong. You think symmetrical and full duplex mean the same thing. They don't. I also used to think they meant the same thing, but different from you.
If you want to learn:
http://www.openface.com/connectivity/everything-you-ever-wanted-to-know-about-fiber-optics/
http://www.computerworld.com/article/2471939/networking/back-to-basics--duplex-and-symmetry.html
I like how this ISP explains their service:
http://www.towerstream.com/symmetrical-internet-connections/
Meaning you can get symmetrical connections that aren't full duplex.
tl;dr symmectrical and full duplex are two separate things.
I have other sources too if you need more info.
Geoff.D
Honorary Master
Fascinating to watch technocrats digging holes for themselves with the interpretation of such basic concepts!
The answer is guys, go and look up on the Internet what Asymmetrical and Symmetrical means and the same with what Simplex, Half Duplex and Full Duplex means before getting bogged down in how technologies work.
Know the history of LAN technologies ( which are not by default symmetrical and full duplex) as compared to full transport and transmission networks ( which are both symmetrical and full duplex).
And then do not confuse this with what the end user perceives is happening. The simplest is to go back and make sure you fully understand how a telephone works before getting into a debate like this.
Update:
And BTW looking at the marketing BS issued by an ISP is the last place to get a true feeling for what is going on because they are the ones that use terms interchangeably and mostly they get it wrong as well (or at best only partly correct).
The answer is guys, go and look up on the Internet what Asymmetrical and Symmetrical means and the same with what Simplex, Half Duplex and Full Duplex means before getting bogged down in how technologies work.
Know the history of LAN technologies ( which are not by default symmetrical and full duplex) as compared to full transport and transmission networks ( which are both symmetrical and full duplex).
And then do not confuse this with what the end user perceives is happening. The simplest is to go back and make sure you fully understand how a telephone works before getting into a debate like this.
Update:
And BTW looking at the marketing BS issued by an ISP is the last place to get a true feeling for what is going on because they are the ones that use terms interchangeably and mostly they get it wrong as well (or at best only partly correct).
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pinball wizard
Honorary Master
No.