[SensorNetArch] Fragmentation & Reassembly

[Cheng Tien Ee]

I'm thinking about layering, especially the SP layer, which seems 
necessary if we assume that the network may be heterogenous and 
therefore can have different MAC layers. I think fragmentation 
definitely implies that some sort of temporary storage is required. A 
question would be: if the application passes a 100byte payload, that is 
fragmented into 50byte-sized fragments at SP, and further split into 
20+byte ones at the MAC layer, does this mean that temporary storage of 
fragments need to be present at each layer? Or perhaps we should just 
leave the fragmentation to the application (it can choose to use flash 
for storage for instance), bound the maximum packet size across layers 
to be some number based on the worst case MAC layer, then, as Joe 
mentioned, use packet aggregation if another MAC layer can transmit at 
higher rates and therefore more able to support a larger packet size?