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Hello all, need some feed back on the following:

802.11 standard says that "adjacent channel" does not over lap but "neighboring channel" does.  Some places tend to inter change the terms but following the standard and for certification purpose we need to stick with 802.11 standard I understand that part.

Now if we look at 2.4GHz spectrum "adjacent channel" does in fact overlaps for instance:

Channel 1 - Center Frequency - 2.412

Channel 2 - Center Frequency - 2.415

Since they are only 5MHz apart and each channel has 20MHz bandwidth they do overlap

Now on 5GHz "adjacent channels" don't really overlap:

Channel 36 - Center Frequency - 5.180

Channel 40 - Center Frequency - 5.200

Since they are 20MHz apart and the bandwidth is 20MHz overlap will be very minimum

So just trying to understand the 802.11 statement in regards to the "adjacent channels" do not overlap because in 2.4GHz spectrum they actually do.  Thank you

Really good question ... Here is the CWNP interpretation 

Read: https://www.cwnp.com/wp-content/uploads/pdf/cwnp_exam_terms.pdf 

The CWNP Program has decided to define two separate terms for clarity: Adjacent Overlapping Channel (e.g. channels 1 and 2 that are overlapping, and are directly next to each other in the band) and Adjacent Non-overlapping Channel (e.g. channels 1 and 6, that are the first immediately side-by-side channels that do not overlap). Channels 1 and 7, 1 and 8, etc are simply considered Non-overlapping channels, and are not adjacent. 

HTH

Thank you I got 404 error.

Ill host it from my drop box also check out the other link on the subject. Let me know that you got it so I can kill the links..

https://www.dropbox.com/s/pzdpy9h9qv8kby9/cwnp_exam_terms.pdf?dl=0 

https://www.dropbox.com/s/10jtwpo4sl2a0gc/What%27s%20YOUR%20Definition%20of%20Adjacent%20Channel.doc?dl=0

Thank you for the files excellent ready hate to say it however I kinda get it but a bit confused.  Here are my thoughts:

So when it comes to the CWNP program and CCNA Wireless it goes by what the industry uses 802.11 i.e Adjacent Channels do not over lap.  The way they are defining Adjacent channels for instance in 2.4GHz range are 1, 6 and 11 and considering the rest as neighboring channel.  So as long as the channel has 25MHz space they will be considered adjacent for instance 1, 6 and 11.  At the same time in 5GHz 36 and then 40 but 5GHz 37, 38, 39 are just not used.

And if its 2.4GHz DSSS its 30MHz because the channels are 25MHz wide vs 20MHz in OFDM.

Is my understanding correct?  Thank you again.

That is the way I understand it, yes. But here again someone can argue the point as being channels 1,2,3,4,etc .. Vs 1,6,11. 

Thanks so much for all your help.

No problem. Glad I could help ..