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LAUNCHCC3220MODASF: Can I Use mDNS with CC3220 in AP Mode? If so How?

Forrest Erickson
Genius 4125 points
Part Number: LAUNCHCC3220MODASF


We are developing a product with the CC3220MODASF device in it. We intend to have our product present the WiFi as an Access Point.

Our firmware is based on the network_terminal example and I was reading about and wanting to try the mDNS to advertise our product device name.

Working with the network_Terminal example I found I could only get the mDNS server to turn on with out reporting an error if I made the CC3220 a STA and connected to the WiFI network here at work. Then I was able to set up the mDNS and find the launchpad with a Bonjour Browser application on my desk top computer.

Here are the commands to set up the Launchpad:

wlanconnect -s "ournetworkSSID" -t WPA/WPA2 -p "ournetworkPW"

mdnsadvertise -n Launchpad5D1B -st Turbo -so "UDP" -t "Entabulator"  -p 5052

Here is the Bonjour Browser output.

Note the browser is reporting _http._tcp even though I set the service for UDP above.

Is there a way to run the mDNS on the CC3220 when it is in AP mode?

Does anyone know of a mDNS client that reports all of the fields of data in the mDNS protocol?

Note search for Hobbyist Software to find the down load for the free Bonjour Browser.

  • 0
    TI__Mastermind 22935 points

    Hi Lee,

    I'm not sure if mDNS works in AP mode. However, since the CC3220 is in AP mode you could just use the internal DNS server for the same purpose.

    More information section 5.6 here.

    Jesu

  • 0 in reply to Jesu
    Genius 4125 points

    Hello Jesu,

    Thanks for the reminder about the DNS server.

    On some reflection I have to ask is there is quite a difference between mDNS and DNS that I had not thought through and for which I may not have the correct vocabulary and mental model.

    The mDNS information was broadcast out the network to which the CC3220 STA was connected. That means the network is connected and operating at at least Layer 4 of the OSI model (because we are using UDP).

    When the CC3220 is in AP mode there is no network till a station connects. Is the DNS still operating at Layer 4 as clients (such as my Galaxy 7 phone) are searching for networks to which to connect?  Is my phone actually making a brief network connection at layer 4 to all of the networks it is showing me as possible WiFi access points?  Or is the connection at a lower layer.

    Anyway I will go read more about the DNS server in SWRU455 (and no doubt the wikipedia page).

    Regarding my question, "Does anyone know of a mDNS client that reports all of the fields of data in the mDNS protocol?"  Perhaps I should have asked, "Does anyone know of an Android app example that reports all of the fields of data in the DNS protocol?"

    Thanks,

  • 0 in reply to Forrest Erickson
    TI__Mastermind 22935 points

    Hi Lee,

    By protocol, mDNS and DNS are practically identical but the circumstances in which they're used are different. mDNS is used when you want to discover services within a WLAN network. This is where mDNS shines because you wont have to setup a dedicated DNS server to discover locally. This is because mDNS support multi-cast (in the name) which implies devices can rely on each other to discover services instead of a dedicated DNS server that needs to keep track of a list of all available services.

    I don't have much experience using mDNS so I'm not aware of what tools are available.

    Jesu

  • 0 in reply to Forrest Erickson
    TI__Mastermind 22935 points

    Hi Lee,

    I'm not sure what you mean by "still operating at layer 4"? Also I'm not sure if you're referring to the 4 layer internet model or the 7 layer OSI model. If you mean the 4 layer model then you're correct, DNS does run at that level because it's an application level protocol. Regarding the connection your phone is making, if you mean the phone to the AP, this happens on the link layer (layer 1) because that is handled by WiFi (802.11). There is no persistent connection at the application layer or transport layer for that matter when talking about DNS or mDNS. This is because they both use UDP socket which are connection-less protocols. 

    Jesu

  • 0 in reply to Jesu
    Genius 4125 points

    Still wondering,

    Is there a way to run the mDNS on the CC3220 when it is in AP mode?

    Does anyone know of a mDNS client that reports all of the fields of data in the mDNS protocol?

    Thanks,

  • 0 in reply to Forrest Erickson
    Guru 39650 points

    Hi Lee,

    According my experiences is mDNS not functional at AP mode. If you need mDNS protocol in AP mode, you can implement mDNS in host code. This will not be a hard to do. Even easier way will be implement own discovery protocol based on UDP broadcast. For example I use for this job at CC3220 modified Lantronix Discovery Protocol. For discovering at Windows without 3rd party software machines may to be interesting LLMNR protocol.

    Jan

  • 0 in reply to Hnz
    Genius 5085 points

    Hi Lee,

    MDNS is only possible in station mode for AP mode it is not provided by SDK. You can go with Jan's idea.