802.11 Standard - "Maximum Allowable Streams"

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Hi,

Please excuse my newbie question:
These questions are related to 802.11 connections. I’ve seen a course note material that stated:

802.11 a – have 1 Maximum Allowable Streams
802.11 b – have 1 Maximum Allowable Streams
802.11 g – have 1 Maximum Allowable Streams
802.11 n – have 4 Maximum Allowable Streams
802.11 ac – have 8 Maximum Allowable Streams

Q1: What does “Maximum Allowable Streams” mean? Is it related to a Half and Full Duplex connections?
Q2: Does “Maximum Allowable Streams” mean to say that you have 1, 4, or 8 antennas needed to stream a data? If so..
Q3: What is the minimum or maximum suggestive antennas that can be physically installed in these 5 Access Point standards?
Q4: Someone says to me that, logically, every stream should produce a “half-duplex” connection per stream. So if 802.11n AP has 2 or 6 antennas in total, is it like 1 or 3 antennas are transmitting data and the other 3 are receiving data all at the same time (MIMO)?
Q5: How about the 802.11 a to g? Am I right that they are only running at “half-duplex” mode because only 1 stream is allowed?

Again, sorry for this newbie question. I just wanted to make sure that I understand this "Maximum Allowable Stream" in 802.11 Standards before I move on to the next topic.

Thanks in advance,
Junie

@Junie-Galvan said in 802.11 Standard - "Maximum Allowable Streams":

Hi,

Please excuse my newbie question:
These questions are related to 802.11 connections. I’ve seen a course note material that stated:

802.11 a – have 1 Maximum Allowable Streams
802.11 b – have 1 Maximum Allowable Streams
802.11 g – have 1 Maximum Allowable Streams
802.11 n – have 4 Maximum Allowable Streams
802.11 ac – have 8 Maximum Allowable Streams

Q1: What does “Maximum Allowable Streams” mean? Is it related to a Half and Full Duplex connections?

If you're using wireless, the reality is that you're either sending or receiving data-single in or single out. Each standard mention with the maximum allowable stream means that this is it's operation capacity (send or receive, not simultaneous). The answer to your follow up question is "Yes." It is related to the concept with Half Duplex, you're sending or receiving; with Full Duplex, you're sending and receiving.

Q2: Does “Maximum Allowable Streams” mean to say that you have 1, 4, or 8 antennas needed to stream a data? If so..

Yes and no. If you want full duplex, regardless of media, you want to send and receive simultaneously. To do so you would need separate channel to do send and another to receive.

Q3: What is the minimum or maximum suggestive antennas that can be physically installed in these 5 Access Point standards?

The standard sets this as what is listed above. If you buy a SISO (Single IN, Single OUT) then only one is needed if you buy a MIMO ( Multiple IN, Multiple OUT) there is probably no physical limitation except for size of device and acceptable interference levels which is beyond what I know.

Q4: Someone says to me that, logically, every stream should produce a “half-duplex” connection per stream. So if 802.11n AP has 2 or 6 antennas in total, is it like 1 or 3 antennas are transmitting data and the other 3 are receiving data all at the same time (MIMO)?

If the device is Full Duplex, it means you have multiple channels receiving and sending simultaneously. So if you have 8 streams that are max allowed. It means 4 of those are probably used for sending and 4 are used for receiving. Can it operate at 8 single half-duplex, possibly, but I couldn't say this for sure.

Q5: How about the 802.11 a to g? Am I right that they are only running at “half-duplex” mode because only 1 stream is allowed?

Yes! That is the nature of those standards and it's operates on CDMA/CA to insure that loss of traffic is minimum if not nearly impossible.

Again, sorry for this newbie question. I just wanted to make sure that I understand this "Maximum Allowable Stream" in 802.11 Standards before I move on to the next topic.

That's why were here. I don't know everything, or even anything at times but you've the resource of the entire ITProTV team and membership that are more than happy to jump in to help each other out here! Thanks for being a member!

Thanks in advance,
Junie

Hi Ronnie,

Thank you for answering my questions :)
Below is my follow-up responses and additional questions:

Ronnie's: "(send or receive, not simultaneous)”
ME: is it because that modern APs nowdays are trying to avoid or lessen a data collision wirelessly?

Ronnie's: “Yes! That is the nature of those standards and it's operates on CDMA/CA to insure that loss of traffic is minimum if not nearly impossible.”
ME: Are we also using CDMA/CA to a wireless connection? For the course of my Network+ studies, we use CSMA/CA for Access Points. Am I right?

Ronnie's: "The answer to your follow up question is "Yes." It is related to the concept with Half Duplex, you're sending or receiving; with Full Duplex, you're sending and receiving."
ME: Am I right in my understanding that these antenna/s are synchronously sending and/or receiving data (half or full duplex) per second of stream? Putting it into scenario; if 802.11n has 4 max. allowable stream, is this Access Point's antenna/s are synchronously sending 2 stream of data per second, and synchronously receiving 2 stream of data per second?
Or is it varies depending on the arrival and transmission of data wirelessly?

New Question: If in case that I have 4 antennas in 802.11n, does it mean that the theoretical maximum speed will be divided into 4?
If so, is it also implemented to other 802.11 standards?

Ronnie, I am really confused and struggling on how to logically explain this "Maximum Allowable Stream" to myself. Honestly, I am still trying to analyze this deeply as I am typing this. Though, I am quite confident that I got the idea of Maximum Allowable Streams in 802.11 a to g.
If you have a hard time understanding my questions or explaining this to me, you can freely refer me back to one of our videos, and I'll just simply watch it. I am more on "visually-learning" type of person too.

Thanks a lot,
Junie

@Junie-Galvan said in 802.11 Standard - "Maximum Allowable Streams":

Hi Ronnie,

Thank you for answering my questions :)
Below is my follow-up responses and additional questions:

Ronnie's: "(send or receive, not simultaneous)”
ME: is it because that modern APs nowdays are trying to avoid or lessen a data collision wirelessly?

I don't think it's about conservation as much as it's about the physics or mechanics of the media and technology. A single channel or frequency can carry ONE signal at a time; it cannot do more than that at one time.

Ronnie's: “Yes! That is the nature of those standards and it's operates on CDMA/CA to insure that loss of traffic is minimum if not nearly impossible.”
ME: Are we also using CDMA/CA to a wireless connection? For the course of my Network+ studies, we use CSMA/CA for Access Points. Am I right?

Yes we are using the CDMA/CA for wireless and Yes for Network+, it's CDMA/CA for wireless nodes and APs.

Ronnie's: "The answer to your follow up question is "Yes." It is related to the concept with Half Duplex, you're sending or receiving; with Full Duplex, you're sending and receiving."
ME: Am I right in my understanding that these antenna/s are synchronously sending and/or receiving data (half or full duplex) per second of stream? Putting it into scenario; if 802.11n has 4 max. allowable stream, is this Access Point's antenna/s are synchronously sending 2 stream of data per second, and synchronously receiving 2 stream of data per second?
Or is it varies depending on the arrival and transmission of data wirelessly?

They are "synchronous" in the fact they can transmit at the same time. As far as the rate it's usually transmitted in terms of bps or Mbps so a single stream can transmit data in either direction in megabits per seconds. Your scenario is correct, I believe that you'll have two streams that will be used for transmitting or sending.

New Question: If in case that I have 4 antennas in 802.11n, does it mean that the theoretical maximum speed will be divided into 4?
If so, is it also implemented to other 802.11 standards?

Yes, this how that works. Take 802.11n for example, max throughput of 600Mbps (from what I remember being advertised). The way that works is that you have 2 antennae used for sending @ 150 Mbps and 2 for receiving @ 150 Mbps.

Ronnie, I am really confused and struggling on how to logically explain this "Maximum Allowable Stream" to myself. Honestly, I am still trying to analyze this deeply as I am typing this. Though, I am quite confident that I got the idea of Maximum Allowable Streams in 802.11 a to g.
If you have a hard time understanding my questions or explaining this to me, you can freely refer me back to one of our videos, and I'll just simply watch it. I am more on "visually-learning" type of person too.

I'll answer what I can but I don't say that I understand everything there is down to the electrical engineering of things. So I may wrong on some of the technical details. I can only tell you that you're going way beyond what you'll need to know for the Network+ exam. If you're in a time crunch for the exam, you may want to make sure you cover other topics that you need to as well. This can always be more of a research hobby that leads to a certification in wireless.

Thanks a lot,
Junie

Hi Ronnie,

Yes, I'm quite in a deadline right now in finishing my Network+ studies. You are right about that, I really feel like I am stepping beyond the scope of this certification. I just had this thought that I should know the answer of this question so the next time I encounter it, I don't have to go back into a situation where I am struggling in looking for a right answers again.

I will follow your advice of doing this as a research in the future.

For now, I have to pass this Network+ certification soon.
Thank you for answering all of my questions in this thread. I really appreciated it :)
I'm going to save this on my journal for my future references.

Kind Regards,
Junie