[Tinyos-help] Question

[Omprakash Gnawali]

On Sat, Jan 17, 2009 at 5:13 AM, Elpiniki Tsakalaki <tsel at ait.edu.gr> wrote:
> Dear all,
>
> I am using Route and Surge in order to have a multihop sensor network. I
> would like the nodes to forward packets to the root/gateway. The packets
> have a unique ID and are broadcasted to the network by an external node
> which is not part of the network. However, I would not like the nodes to
> forward more than once a packet with a specific ID. Therefore, the gateway
> should receive only once a packet with a specific ID.
>
> How could I check if a packet is forwarded more than once? How could I
> have in every node the information of which IDs have already been
> forwarded by that node?
>
> I should mention that the packet IDs are increasing - So my initial
> thought is to use a variable to store the ID that has been forwarded (and
> compare against lower ID values) but I do not know how to do this on per
> node basis.
>

To avoid duplicates at the root, each forwarding node should transmit
a packet once. The delivery ratio might be less than 100%.

If the routes change, keeping a cache of packet signature won't
necessarily help.

- om_p