[lwip-users] [lwip] Intention of poll,tcp_output() in tcp_slowtmr() call.

[Michael Portmann]

Hi all.

  I think this is a bug, however...

  Can someone (Adam?) explain the intention of the call poll,tcp_output() in 
tcp_slowtmr().
Both V0.5.3 and CVS call it at the rate of the pollinterval. What this means is 
if you haven't filled up to MSS worth of data, the data won't be sent until the 
poll call.

  My understanding from documentation I've read, is the poll is for "watchdog" 
type functionality.

  What is the "normal" delay used for transmitting packets less than MSS ? I 
feel this should be either changed such that tcp_output() is called at every 
tcp_slowtmr() call (500ms) or that the documentation be changed to mention that 
the poll() call has this effect.

  Finally on this matter - I can't see where this pollinterval is initialised 
except for by the tcp_poll() function (Not even bzero'ed.) Would it be 
reasonable to say pollinterval should be initialised to zero in the tcp_input 
function ?

Regards,
Michael Portmann

HYDRA Electronic Design Solutions Pty Ltd
140 Ashley Street, Underdale, SA 5032.
Ph. +61 8 8234-0477
Fx. +61 8 8234-1840

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