* MIB Information

The following is tentative information that I was able to gather about the undocumented*   MIB variables used in Lucent-powered wireless access points like the Apple Airport and Lucent RG1000. These variables are used in wireless link testing; the procedure for this is outlined below, identifying the role of 27 of the variables in this group. I’ve used these successfully in constructing a link-test Java application.

Wireless Link Testing

Wireless link testing seems to require several steps:

  1. Set the following OID’s to the specified values:
    • Set value to 50:
    • Set value to 3:

    I don’t know what these values represent, but the following stuff won’t work if these sets are not done…. Note that this and the other “sets” below require that the SNMP read/write community name (“password”) be used.

  2. Retrieve the value of OID;  this gives the number of wireless hosts known to the access point. I’ve found this to be somewhat glitchy, at least with the Apple Airport Base Station: it often takes a number of tries before the value returned is the actual number of hosts (a value of 0 being returned in the interim).
  3. Determine which index corresponds to which host by retrieving the value of some of the following OID’s:
    Wireless host name
    Wireless host MAC address

    In the above,  n  is one of the indices from 1 to the number of hosts retrieved in the previous step. Use this information to select the wireless host whose link is to be tested. (Note, however, that I’ve seen the index value / host mapping change between retrievals…  not sure why…) Interestingly, this permits testing of any of the wireless links, not just the one corresponding to the host doing the SNMP queries. In fact, this can be done from any host, even one that’s not part of the wireless network.

  5. For the selected host index  n,  set the values of the following MIB’s:

    Packet size?
    Number of packets to send?

    This sets the value of parameters for link test polling, which begins as soon as the last parameter (number of packets?) is set.

  7. Read the values of the following OID’s to retrieve statistics about the link quality polling. In the following, “local” refers to the base station, while “remote” refers to the wireless host on the link being tested. (I _think_ this is correct, but I might have it backward…)

    Local signal strength, current
    Local signal strength, minimum
    Local signal strength, maximum
    Local noise strength, current
    Local noise strength, minimum
    Local noise strength, maximum
    Local signal-to-noise ratio, current
    Local signal-to-noise ratio, minimum
    Local signal-to-noise ratio, maximum
    Local packets received successfully (?)
    Local packets received total
    Remote signal strength, current
    Remote signal strength, minimum
    Remote signal strength, maximum
    Remote noise strength, current
    Remote noise strength, minimum
    Remote noise strength, maximum
    Remote signal-to-noise ratio, current
    Remote signal-to-noise ratio, minimum
    Remote signal-to-noise ratio, maximum
    Remote packets received successfully (?)
    Remote packets received total

    To do repetitive testing, repeat steps 4 and 5; when finished testing, set the value of OID  to  0.

Computing, lutherie, mathematics, finance, and other resources