On Thu, Aug 28, 2008 at 1:14 AM, Michiel Konstapel <[EMAIL PROTECTED]> wrote: > Following up on my message about the link estimator, I was also wondering > about CTP's parent switching threshold. As is, CTP will switch parents if > the new parent offers a path ETX that is 1.5 hops better than its current > parent, if I am not mistaken. Now, this is set fairly conservatively, > because a node would not replace a two-hop, 2.4 ETX parent with a direct, > perfect link to the sink. However, "in the back" of the tree, where lots of > link ETXs are added up, you don't want a low threshold or nodes would switch > parents all the time.
I want you to point to some related discussions about this: http://mail.millennium.berkeley.edu/pipermail/net2-wg/2007/000723.html http://mail.millennium.berkeley.edu/pipermail/net2-wg/2007/000729.html > Now, would it be an idea to base this threshold on a percentage of the path > ETX? For example, at 20%, a node with a path ETX of 2 would replace its > parent by one that offers a path ETX of 1.6, whereas a node that has a path > ETX of 10 would only switch if the new path has an ETX of 8 or lower. That > way, it would favour optimal routes near the sink, where traffic is highest, > and favour stable routes further down the tree. A cap would probably be > needed on top of the percentage, so that it doesn't become impossible to > switch in very large networks. It is definitely an interesting idea. You will notice that MultihopLQI uses a similar approach. We haven't tried this for CTP. What did you observe in your experiments? - om_p _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
