[net2-wg] Collection

[Rodrigo Fonseca]

I added an interface -- CollectionDebug -- which allows for easy
calling of debug messages. I have implemented one of the commands in
UARTDebugSenderP, and am finishing the others. Should make sending
these msgs much easier.

Rodrigo



On 6/14/06, Kyle Jamieson <jamieson at csail.mit.edu> wrote:
> With Rodrigo's help, I've instrumented the FE with calls to send
> diagnostic packets to the uart in case of exceptional circumstances.
> Those could be:
>
> - message pool empty
> - send queue full
> - no route from the router
> - subsend is off
> - subsend is busy
> - senddone from subsend doesn't make sense
> - queue entry pool empty
>
> Now we can see more of what's going on in the FE.
>
> Philip Levis wrote:
> > 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
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