Wireless Access

What is the current state of client DFS support? 

 

Is DFS ready for global use in a HD campus environment or should it still be limited to locations that are also covered by non-DFS channels?

 

Also, did the AP-105 ever get DFS support?  For a long time I know it wasn't supported (despite the DS saying it was).  Also are there other APs that don't support DFS?

 

Best

 

 

Assuming that your country is the US, the AP105 does have DFS support (AOS 6.3.1.7)

 

 

---

(192.168.1.3) #show ap allowed-channels country-code US ap-type ap-105

Allowed Channels for AP Type ap-105 Country Code "US" Country "United States"
-----------------------------------------------------------------------------
PHY Type                 Allowed Channels
--------                 ----------------
802.11g (indoor)         1 2 3 4 5 6 7 8 9 10 11
802.11a (indoor)         36 40 44 48 52 56 60 64 100 104 108 112 116 132 136 140 149 153 157 161 165
802.11g (outdoor)        1 2 3 4 5 6 7 8 9 10 11
802.11a (outdoor)        52 56 60 64 100 104 108 112 116 132 136 140 149 153 157 161 165
802.11g 40MHz (indoor)   1-5 2-6 3-7 4-8 5-9 6-10 7-11
802.11a 40MHz (indoor)   36-40 44-48 52-56 60-64 100-104 108-112 132-136 149-153 157-161
802.11g 40MHz (outdoor)  1-5 2-6 3-7 4-8 5-9 6-10 7-11
802.11a 40MHz (outdoor)  52-56 60-64 100-104 108-112 132-136 149-153 157-161
802.11a (DFS)            52 56 60 64 100 104 108 112 116 132 136 140

 

With regards to client support, there are quite a few like Motorola phones for example that do not support DFS.  For every client that does not support DFS you would be creating a "coverage hole" or making the 2.4ghz side of the access point more attractive which would sort of defeat the purpose of having 5ghz rates in the first place.  If you have a high density environment and only run 20mhz channels with no DFS, you would still have 9 channels to deal with, which in many environments is very  good.  Organizations that have full control over the majorityof their clients that they desire to do DFS have a better chance of success in a setup with DFS.

 

Thanks Colin.  I'm in US EDU so I have zero client control.

 

Practically everything is HD here so the extra DFS channels would help considerably.  I don't however want to make wifi unusable for any of my users.  If the percentage of my clients that didn't support DFS was low enough it could make since to push them to 2.4 so everyone else benefited, but it would have to be a very low % (<5%). 

 

It sounds like we should limit our DFS usage to select areas for now.

 

Thanks again

 

 

 

If it's a very dense deployment...other than DFS, have you considered 20 MHz channels?  

Yes it is very dense and we came to the same conclusion.  We're exclusively using 20MHz channels.  In most places we get by okay with the non-DFS channels, but we also have quite a few locations that could use more.

 

Dense, multi-story buildings can be a real challenge.  By the way, can we all just vote to turn 2.4 off - forever.

Rdholden,

Please let us know how it goes. Everyone's environment is different so let us know what works in yours so others can benefit.