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Posted by:dragorn
Subject:Monitor PER?
Date:18:09:58 31/05/2006

> I'm currently looking to do some site surveys and other tasks and I feel that being able to monitor the Packet Error Rate (PER) would be quite helpful. However, I do not have the funds to purchase the 802.11b YellowJacket Reciever nor do I have the money to purchase the full version of Airopeek from WildPackets.
> I am hoping someone could provide me with another solution until the funding is available to purchase Airopeek.

The problem is, the firmware doesn't expose packets which fail the checksum.

One thing I'm planning to add in newcore is a "missed packets" identifier, which will attempt to guess the missed packets by counting beacons per second. It won't be useful during channel hopping, and it's still just a guess, but it's a moderately reliable method, and the same mechanism that firmware/drivers use for detecting when they need to move to a stronger AP.

Newcore already tracks packet retries, which is to some extent an indicator of network error rates.

So, not a complete answer, but perhaps the beginning of one.

Newcore supports plugins, as well. It's conceivable that you could write a traffic injector and then use a plugin which monitors the packet rates. If you did this on a transmitter where you could bypass the firmware retry, or if you had fine-grain timing on the receiver so you could detect errors and retries (or listen to the retry flag in the packet) and deduce error rates from that.


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