Jiliang Wang writes: > Yes, there is channel scanning. Actually I have a question here. By > current scanning mechanism, does it mean there is no guarantee for a > scanning node and beaconing node to meet? Meanwhile, it may also take a > long time to for two nodes to meet.
Yes. If you do scanning do fast or incorrectly it is possible that you never hear EB. On the other hand if you do it so that you are sure to hear the EBs it might take tens of minutes... You can of course do all kind of implementation depending things to make this better. For example if you do energy detection on the channel first. If there is nobody ever on the channel for long time, that might mean that channel is not part of the schedule, and listening it might not be useful. On the other hand if there is too much energy on the channel, it might be because there is some other radio transmitter on the channel, and it might not be used for channel hopping because of that reason. If you hear any 802.15.4 TSCH frames on the channel, you can assume that this channel is in the current channel hopping sequence, and if network is set properly there should be EB on the channel at some point of time. On the other hand you might need to wait for it for EB_PERIOD * slotframe size * timeslot length * number of channels * n, where n depends how many dropped beacons you want to wait. I.e. with typical settings this might be few minutes. If you do not see EB during that time, you move to next channel and repeat... -- [email protected] _______________________________________________ 6tisch mailing list [email protected] https://www.ietf.org/mailman/listinfo/6tisch
