Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Wireless Full duplex.

Dear All.

I want some information on cisco wireless, does it support full duplex wireless.

Some other wireless company says, there wireless are full duplex wireless.

I am also looking for some information on how full duplex wireless work.

Everyone's tags (2)
15 REPLIES
Hall of Fame Super Gold

Re: Wireless Full duplex.

Unfortunately, wireless is half duplex.  When a wireless device transmits everyone stops and listens.  The only full duplex is the wired link.

Re: Wireless Full duplex.

As Leo points out. A wireless AP is like a HUB in the air. The medium works on CSMA-CA. Only one client can occupy the channel at a time.

__________________________________________________________________________________________ "Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin ___________________________________________________________
New Member

Wireless Full duplex.

Hi Scott,

I completely aggree with you, that Wireless is Half duplex since it uses the complete channel at one time and rest of the clients just listen to the traffic for their turns. I have read the CSMA/CA as well that how does it works.

My query is - When using applications like Torrent, it shows the download and upload happening at the same time. How come it is possible ? Is it just that we see but actually doesn't happen at the backend ?

Can you share some good document or link to make it more clear to me.

Thank you !

Regards

Harish

New Member

Wireless Full duplex.

Also, One more querry - Once the medium is reserved by a Client for the frame duration value and rest of the clients increases their NAV and starts counting down.

What will happen if the Client A gets shuts down in while sending the traffic to AP. Will the Rest of clients like Client B will initiate sending traffic to AP or Will complete its Count down of NAV ?

Hall of Fame Super Gold

Wireless Full duplex.

When using applications like Torrent, it shows the download and upload happening at the same time.

How many clients are connected to the same WAP and seeding Torrent?  One?  Two?  Get a dozen and you'll see. 

New Member

Wireless Full duplex.

around 10 clients and using torrent

Hall of Fame Super Gold

Re: Wireless Full duplex.

around 10 clients and using torrent

You should see effects of your wireless when you are all seeding and downloading something popular.

Geez, I sure don't want to know what the cycle rate is.

What kind of ethernet uplink does the WAP have?

Re: Wireless Full duplex.

Harish:

You said "" Is it just that we see but actually doesn't happen at the backend ?""

this is 100% correct. The half-duplex between you and the AP is very fast (microseconds) so say every 30 micro seconds one can send and no-one except this one can send and all should wait for him/her to finish sending. after s/he finish other clients will try to to send (one at a time). so for 1 second many clilents can send multiple times. This is how it goes. For your torrent it shows you the bandwidth in layer 3 speed. it just cares about how much data you send and receive in a second. (this is why it is kbps: Kilobit per SECOND). This means the total effective speed you are allowed to send/receive in one second. This transmission is not done continuously in layer 2 because you have a few microseconds everytime you'd like to send. but in total you are able to send with X speed in one second.

Got it?

Hope this is clear enough to you.

Amjad

Rating useful replies is more useful than saying "Thank you"
New Member

Re: Wireless Full duplex.

Amjad, Thanks for clearing it to me. It was really helpful.

Re: Wireless Full duplex.

Not to throw a wrench in this .. But 80211ac will allow for full duplex like connections

Just an FYI

Sent from Cisco Technical Support iPhone App

__________________________________________________________________________________________ "Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin ___________________________________________________________

Re: Wireless Full duplex.

George:

I think 802.11ac is going to support full duplex like connections because both senders and receivers have multiple

antennas (MIMO). For example; an STA will have two antennas, one for sending and one for receiving. the send/receive processes will be done on different channels (or different spatial streams). Having about 160 MHz of channel width will make it easy to achieve this.

Rating useful replies is more useful than saying "Thank you"
New Member

Wireless Full duplex.

Re: Wireless Full duplex.

802.11ac is not full duplex, but full duplex like.

__________________________________________________________________________________________ "Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin ___________________________________________________________
New Member

Wireless Full duplex.

Full Duplex wireless is possible........... Just not available..........

http://sing.stanford.edu/fullduplex/

Wireless Full duplex.

So is time travel ..

__________________________________________________________________________________________
"Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin
__________________________________________________________________________________________
‎"I'm in a serious relationship with my Wi-Fi. You could say we have a connection."

__________________________________________________________________________________________ "Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin ___________________________________________________________
3655
Views
10
Helpful
15
Replies