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Firmware Flowchart

Discussion in 'Cisco/Linksys Wireless Routers' started by orangemonkey, Jun 12, 2007.

  1. orangemonkey

    orangemonkey LI Guru Member

    I've asked similar questions with few results but here goes. I have a small network at my business and I get to a point where our computers stop communicating. The solution every time is to power cycle the Cable modem BEFSR41 router and 24 port switch. I have yet to read a discussion of the actual programs running inside these devices. Is this stuff top secret or just to complicated for the average guy to understand? Obviously something stops or clogs up or runs out of room and the power cycle clears the problem but why can't I find the discussion group that says 'oh yea and when the z table hits line 25 it tips the lever spindle which releases the cheese and the mouse is trapped in the glass jar'. Where are all the engineers??? Does anyone understand the inner workings of these things??

    Thanks for your time,
     
  2. mstombs

    mstombs Network Guru Member

    The BEFSR41 runs a proprietary OS and is designed for small home use, only the designers know what it does in detail. Not surprised it can't cope with a 24 port switch behind it. If you upgrade to a WRT54GL (L for Linux) and make your choice of 3rd party firmware you would be able to see what was going on even if you turn the wireless off and don't use it. Any device that does NAT translation must maintain a table of which device initiated which connection and keeps all entries for some time. It is likely this table fills up, and reboot clears IMHO
     
  3. orangemonkey

    orangemonkey LI Guru Member

    Thanks for confirming there would be a table in there. I don't think I'll go the Linix route though. But where do programmers get the specs in order to create their own firmare? Is this made available by Linksys? Or has someone reverse engineered these things?

    Thanks
     
  4. mstombs

    mstombs Network Guru Member

    For a simple explanation on how nat now works see, for example

    http://www.draytek.co.uk/natmovie.html

    Designers need a basic operating system with custom board support package and development environment. This can be purchased from a vendor such as Windriver - vxWorks and contains only proprietary code (used in later WRT5G's). Apparently the reduction in memory required pays for the license fee.

    Other devices can use micro distributions of Linux, for which, under the GPL, manufacturers must make available copies of the modified sourcecode used. Linksys is now very good about this and most sourcecode distributions are complete and include all the proprietary binary modules to re-build the firmware with your own choice of customization.

    See the Linksys GPL code center on the Linksys.com website for such sourcecode - unfortunately the top of the list ADSL2MUE is not a good example - the published code is particularly incomplete!
     

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