[Tinyos-devel] Re: [Tinyos Core WG] Proposal for VariableSizedQueueC component

[Philip Levis]

On Sep 20, 2007, at 5:47 AM, Prabal Dutta wrote:

> We've encountered a version of this problem in T1 but haven't tried to
> reproduce or characterize it in T2.  When a node is sending a burst of
> packets, for example during a bulk transfer, the inter-packet interval
> (start-to-start) must be somewhat larger than a packet time or else
> single-hop goodput suffers.  We didn't investigate this further at the
> time because packets were being streamed across multiple hops and this
> particular problem wasn't the bottleneck.  However, it might well be
> for a store-and-forward bulk transport protocol.  I suspect the
> problem was timing-sensitive handling of a packet on the receive path
> as Jan suggests.

I think that making changes to the T2 radio stack based on suspicions  
of the cause of a problem on T1 is probably not a good design  
methodology. IIRC, T1 could not handle multiple packets in the RXFIFO  
memory: it would flush them. See the T2 tech report on the possible  
throughput differences. T2 can handle this case, and spools them out.

Phil