Capabilities

• Rendezvous: mobile devices' presence is transient - they are assumed to come and go (as opposed to the fixed nodes that are assumed always on)
• Sensing Management: agreeing on frequency of sensing, reporting
• Timestamping: cannot assume accurate clock at auxiliary nodes
• Semantics: physical quantities corresponding to readings, units
• Heterogeneity: Multiple types of sensing devices
• Robustness: State refresh, soft state

A possible solution:

GET

• Clients are pre-programmed to multicast (or broadcast) measurements with node, ID, sequence number, measurement data, etc. (packet specification available here?).

• The clients multi/broad-cast a measurement until it is ACKed by a server (any of the servers), and then then move to the next measurement - all are stored until ACKed in a circular buffer.

• Simplification: each measurement fits in one packet.

SET

• any server after rendez-vous can set any of the set variables (assumed pre-known, or advertised by the client using broadcast).

• the client does ACK the SET.