27 Nov
2013
27 Nov
'13
9:06 a.m.
Holger Hans Peter Freyther wrote:
Are you referring to 9.1.3.1 "Acknowledge state
array V(B) for GPRS
TBF Mode"?
yes, the protocol sends all unacknowledged blocks in a loop until all
blocks are acknowledged and the tbf is complete.
With statistics in place it appears that for CS4 close
to 50% of the
sent RLC blocks are re-sends. Is that what you expected when implementing
it?
if there is a continuous download (opening a web page), there should be
almost no re-sends unless the window stalls or the download is complete.
in case of a ping with several small tbfs, there are re-sends due to the
delay between PCU and the radio interface: the PCU sends the final block
of a tbf (polling bit set) and then waits for PACKET DOWNLINK ACK/NACK.
higher delay will cause more re-sends for each tbf at the end, so
smaller tbf will cause more percentage of re-sends.