[net2-wg] collection stuff

[Rodrigo Fonseca]

Hi Phil,

just to clarify, you are talking solely about the data path, right?

I am not sure we need anything in the Routing Header for simple
address free collection.
The only thing I can think of is the current hopcount, or the lowest
hopcount seen.

The idea with the getNextHops command is that the FE just asks what
the addresses are for the next hop and adds them itself to the network
header.

Notice that I am not considering the control messages at all, which
are totally separate.

I agree that having send go to LE via the Routing will complicate the
Routing and may be unnecessary.

All the FE needs to know it the size of the routing header if there is
one. This is what is in the RoutingEngineControl interface, but can be
changed.

 interface RoutingEngineControl {
    command error_t initializeRH(message_t *msg, uint8_t tree_id);
    command uint8_t getHeaderSize();
}

The FE.Packet interface takes the Routing header size in its
computations for the Packet interface.

Thanks,
Rodrigo


On 4/20/06, Philip Levis <pal at cs.stanford.edu> wrote:
> On Thu, 2006-04-20 at 16:50 -0700, Philip Levis wrote:
>
> > Because the ForwardingEngine (FE) doesn't fill in the routing header
> > until the packet is about to be sent, changing parents are not a big
> > deal. I think that having the FE call a Send on the Routing Engine is
> > unnecessary, and will just make the Routing Engine more complicated with
> > little gain.
>
> On further thought, this is incorrect: the Routing Engine needs to have
> an Send or AMSend. The reason for this is keeping track of payload
> sizes. If I'm calling the RoutingEngine to calculate my payload size as
> it might be adding headers, I can't then pass these values directly to
> the link estimation component.
>
> E.g., imagine I have an app payload of 5 bytes, a network header of 3
> bytes, a routing header of 2 bytes, and a le header of 2 bytes. The
> sizes:
>
> app payload to network: 5
> network payload to routing: 8
> routing payload to le: 10
> le payload to AM: 12
>
> If my network layer calls routing to compute its payload, it will get 8.
> If it passes this 8 to the LE layer, then it will cut off the last two
> bytes.
>
> Thoughts?
>
> Phil
>
> _______________________________________________
> net2-wg mailing list
> net2-wg at millennium.berkeley.edu
> https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/net2-wg
>