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Transmit only wifi. Master mode in Tomato?

Discussion in 'Tomato Firmware' started by Ken Zakreski, Oct 23, 2012.

  1. Ken Zakreski

    Ken Zakreski Serious Server Member

    Hi
    I'm new to this forum, playing around with OpenWrt and now Tomato with a friend from our local linux group. New to linux from last year when I returned to school to pick up C++ coding experience. My background is in Apple gear and I like linux.

    Wanting to use HTML5 and would like to disable the receive functionality of a router for testing purposes. I will be streaming audio one way over 802.11 and plan to goto a 4 watt router for use on the farm here...

    I cannot see how to easily disable the receive functionality in OpenWrt or Tomato and wonder if it is something that can be easily accomplished from the command line.

    Can anyone tell me how to disable the receive functionality (so the router will transmit only) on a router using Tomato version 1.281816 for my router model Linksys WRT54G v.3? ie. how to set it to master mode*

    One possible work around would be to dedicate receive to one of the antennae sockets and point it to space. I see the option to direct receive to an antennae in Tomato.


    Ken

    *Some terms from http://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/sf08479.html#aa9
    Master mode is an operating mode in which the LE-LAN device has the capability to transmit without receiving an enabling signal. In this mode, the device is able to select a channel and initiate a network by sending enabling signals to other LE-LAN devices.
Slave mode is an operating mode in which the transmissions of the LE-LAN device are under control of the master.
     
  2. mikester

    mikester Network Guru Member

    you could drop all incomming packets using iptables on WLAN but I dont think you would be happy with the results...what are you building a spam or DoS box to take out your ISP/neighbors?
     
  3. Ken Zakreski

    Ken Zakreski Serious Server Member

    Hey mikester,

    Packets must not be received by the router so directing the receive functionality to a directional antennae pointed towards space... or no antennae at all... may do that.

    Why would I not be happy with the results of sending incoming packets to NULL? That sounds like a solution.

    Not building anything nefarious like that. This would be under an experimental license from Industry Canada. I'm adminning the application, and testing the software side to see if html5 can stream one way to a distant client from a 4 watt router. I want to use a micro watt router to start with for testing the html5 part. No neighbors, on the farm here.

    The regulator will allow 4 watts for testing, it's all they can use. I would like to use more but Matt may get upset if I interrupt his municipal links run on a directional service. Plus in the states there is FCC part 15. I'm close to the 49.

    Think HSMM, poor mans terrestrial satellite radio. ibr dtn looks interesting. Targeted user will be for college radio use, not all campuses want FM or the hassle of a regulated channel anymore. Channel selection will be critical due to near space earth stations. Walking on eggshells here. Losing all use of one wifi channel on a even small campus may end this pilot project real quick. http://wihifiradio.blogspot.ca/


    Ken
     
  4. Monk E. Boy

    Monk E. Boy Network Guru Member

    I think you should re-read what was written. It says nothing about not receiving. It says it doesn't wait to receive a signal before transmitting. That does not preclude receiving signals, it just doesn't wait for "slave" to transmit to the master before the master transmits. Sending packets at a source while blocking reception of packets from that source is pretty much only useful for denial of service.

    To join an 802.11 network you will have to both send and receive data. That's just how it is. There are encryption handshakes that take place that requires two-way communication between both parties. In your stated example you would only be able to send packets at a wireless device but not actually communicate with it in any meaningful way. It would keep transmitting back to you for handshaking, key exchange, etc. and never receiving any response back. Again, this is useful for denial of service, but not so useful for much of anything else... well, a microwave oven. Or a traditional radio, where you tune a receiver into a broadcast from a transmitter - but WLANs don't work that way.

    TCP communication itself requires two-way communication that ensures packets are either delivered or the application is notified that packets were not delivered. All TCP communication would be broken.
     

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