Changes between Initial Version and Version 1 of HowTo/bssidFix

Aug 25, 2006, 11:26:43 PM (15 years ago)


  • HowTo/bssidFix

    v1 v1  
     2| !bssidFix
     4= A Solution Ad-Hoc BSSID Partitioning Problems =
     6When wifi network cards are placed in ad-hoc mode (iwconfig ath0 mode 'ad-hoc') they will automatically search for networks with the same essid (iwconfig ath0 essid 'blah'). They will adopt the bssid of the first node to turn on that has the specified essid.
     8Unfortunately, this algorithm and/or implementation is not very good and even relatively small networks nodes that have the same 'essid' will end up with different a 'bssid'. Since the wifi card drivers filter by bsssid, nodes that should be in the same ad-hoc network can't exchange packets.
     10The solution to this problem can be found by modifying the madwifi drivers (for Atheros wifi cards only), so that the bssid a node generates is a hash of the essid instead of its MAC address. This ensures that nodes with indentical essid's end up with identical bssid's.
     12Although it has not been extensively tested with non-modified nodes, this modification to the madwifi drivers should be fully backwards compatible with non-modified nodes.
     14== What to Change ==
     20orbitHandler is an alternative framework for controlling the ORBIT lab. It consists of a series of console commands that that operate on predefined sets of nodes. The major features include:
     22 * Precisely specify large, intricate node sets
     23 * Send specific commands to each node in the set
     24 * Distributed ftp equivalent
     25 * Entirely command line driven
     26 * No global grid operations