Ok, I solved one of the issues.  The Grace Radio has a 802.11n wifi adapter built-in and it is able to connect to the WNDR3800 802.11n WiFi AP.  However, the Grace Radio WiFi is not compatible with the EAP225 802.11n implementation.

I found this out because I changed the EAP 225 to just do 802.11b/g on the 2.4Ghz band, and then the Grace radio was able to connect and actually use the network.  So that's good, but I wanted to see if these would connect on N, so I changed the EAP 225 to just do 802.11n on the 2.4Ghz band and then the Grace radio was again unable to use the network when connected through the EAP225.

So...  the good news is I can use the Grace Radio again... The bad news is that something is off in the implementation of 802.11n on the EAP225.

jorgeC wrote

I have the EAP configured as b/g/n for 2.4Ghz WiFi AP, and a few legacy devices on the network are having trouble using the EAP 225.

 

The legacy devices will either:

 

A) not see the WiFi AP at all (cant find SSID) or

B) see and connect to the SSID, get an IP from the DHCP server, but not be able to transmit any packets after that (even ARP [ping] won't get through).

One device is a Dell laptop (Windows 10) which has an Intel Centrino-N2230 wireless card.  This guy can't see the EAP225 at all (case "A" above)... 

 

Another device is a Grace Digital Radio (GDI-IRD4500M).  This is an internet radio.  This device behaves as case "B" above.  Which is weird... Why would it be able to attach to the SSID, go through the whole DHCP sequence and obtain an address from the DHCP server on the network, but yet not be able to send/receive ANY packets AFTER that?!?  

 

Anyway, any help would be appreciated.

 

PS. All the devices, including the 2 above, which have issues with the EAP225 work just fine with other b/g/n WiFi APs/Routers on 2.4GHz, such as netgear WNDR3800.

 

Hi JorgeC,

For the Case A, we suggest you check the driver of the Intel Centrino-N2230 wireless card, and upgrade it to the latest office version. Does the 2.4G channel width of EAP225v3 is auto, you can set the channel to 40MHz or 20MHz only, then check if the Dell laptop can see the SSID of EAP225v3.

For the Case B, it seems that there may have some compatibility problem between EAP and Grace Digital Radio (GDI-IRD4500M) in 11n mode. Do you have MAC book? You can capture wireless packets between EAP and GDI-IRD4500M(you can refer to FAQ1830: https://www.tp-link.com/en/faq-1830.html), and capture the wired packets of the LAN port of EAP. Then we can see why the radio can NOT access the network.

jonas wrote:

For the Case B...refer to FAQ1830: https://www.tp-link.com/en/faq-1830.html)

@jonas :  I just read the FAQ, it talks about capturing packets using Wireshark on an Apple MacBook.  I have a MacBook Air 2017, do you know if that would work?

jorgeC wrote

jonas wrote:

For the Case B...refer to FAQ1830: https://www.tp-link.com/en/faq-1830.html)

 

@jonas :  I just read the FAQ, it talks about capturing packets using Wireshark on an Apple MacBook.  I have a MacBook Air 2017, do you know if that would work?

Hi,

I think it works. You can just enable the monitor mode in wireshark, then capture the wireless packets between EAP and radio. I suggest you set the security mode of SSID of EAP as "None", it may be easily to check the wireless packets. We may need the MAC address of EAP and Radio to extract the wireless packets for checking.

@jonas , I got the pcap trace of the internet radio device that is having issues using the TPLINK EAP 225 WiFi when BGN is enabled on the 2.4ghz radio.

I was able to see all the beacon frames and then some... Interesting stuff!!!

Anyhow, how do I share the PCAP with you?  I don't want to attach it on here (don't even know if I can) for the world to see.  :-)

I did notice that the DHCP request/offer/answer all go through, so the internet radio (IRD) gets its IP address from the network's DHCP server.  Shortly thereafter, the IRD sends a "request-to-send" packet, to which the EAP 225 promptly responds with "clear-to-send".  However, the IRD either doesn't understand the "clear-to-send", it doesn't like it or it never got it because the IRD just keeps sending "request-to-send" and the EAP keeps responding with "clear-to-send" for several seconds until the radio gives up and displays an error in its display saying "no network connection".

That doesn't happen when these two are connected on a 802.11 B/G only connection.  It only seems to get into that endless loop when 802.11 N is in the mix.  I will see what the difference is in the flags and/or messages, if any, between the IRD and the WNDR3800 dialogues (as compared to the EAP225) when those two connect on 802.11 N.

Anyway, just let me know how to send you the trace so you can have a look please.

[EDIT] I realized after posting the above that wireshark for some reason, does not capture the data packets being sent by the terminals (e.g. IRD) through the EAP225 to the internet server (why is that?!?). So that's why it looks like just a RTS/CTS exchange going on forever...  I realized this because I took the trace with the WNDR3800 and I see the same RTS/CTS exchange and no data packets from IRD to WNDR, but the IRD actually works with the WNDR3800. I do see the responses from the internet server coming back towards the IRD in this test but I do not see those when the EAP225 is providing the WiFi access.

@jonas :  Could you please let me know how to share the pcap traces with you so you can try to determine what's the incompatibility between EAP225 and the IRD?

I am having a ton of intermittent problems with other endpoints and the EAP225 now.  It has gotten so bad that I had to turn off the EAP225 and use my older APs instead.  I am hoping that if we can solve the issue with the IRD, it may also address the intermittent issues between the EAP225 and the other terminals, hence the urgency.

Thanks!

Thanks for the private message @jonas .  I sent you the pcap traces.  As I communicated there, it looks like the issue is related to having the 40 Mhz channel bandwidth enabled, not really the "N" setting.  In other words, if the EAP225 is set "20/40" or "40" channel bandwidth then it has issues with the IRD and others.  But if the setting is fixed to "20 Mhz" then things seem to work just fine, at least they seem to be for the short while I tested, I have not run a long test yet.