[net2-wg] Collection

[Philip Levis]

I see four major places that might be the cause of the problem. There  
are two simple ways to start the diagnosis. The first is packet  
sniffing: use a base station to see who is sending what (if at all).  
The second is to use the LEDs in three specific circumstances.

1) Queueing/buffer management: ForwardingEngineP is corrupting  
packets, dropping packets, or otherwise preventing traffic from  
getting through.
   - Instrument ForwardingEngineP to turn on Led0 when its message  
pool is empty or its send queue is full and send an error message to  
the UART.

2) Route selection/link estimation: The link estimation table is  
oscillating wildly, leading to an unstable tree or there appear to be  
no routes.
   - Instrument TreeRoutingEngineP to turn on led1 when it has no  
route and send a periodic message containing the parent ID to the  
UART. Send a UART message whenever the parent changes.

3) Loops in the routing tree are causing the network to saturate with  
packets, false negatives acks are causing the number of packets in  
the tree to increase greatly.
   - Instrument ForwardingEngineP to count the number of  
retransmissions it makes; if it goes beyond a small number (e.g., 4),  
send an error message to the UART

Does anyone have additional hypotheses/tests?

Phil