RE: Looking for ways to improve CIMD2 protocol performance

Windowing is an optional feature in CIMD2 with a max window size of
128. If you wish to use windowing you have to declare the window size
within the login request using parameter 019 otherwise the SMSC
will set a window size of 1 by default. Current implementation has no
windowing functionality so I modified cimd2_login() in smsc_cimd2.c to
declare the int parameter 019 when sending login request to SMSC just
to check if the SMSC will accept the windowing parameter. The test was
a success and we managed to successfully login using a window size of
32:

2007-06-08 20:40:04 [19247] [6] DEBUG: CIMD2[cimd2_smsc]: sending
<01:001 010:test 011:test 019:32 82>

2007-06-08 20:40:05 [19247] [6] DEBUG: CIMD2[cimd2_smsc]: received:
<51:001 3C>

CIMD2 windowing have two important restrictions. All operations to the
SMSC (keepalive, submit SM etc.) use a window slot not just the submit
SM, so all outstanding operations should *NOT* exceed window size. The
SME is forced to use the packet numbers in strict increasing order
001,003,005 etc.and *NOT* randomly 011,123,009 etc. We must receive
responses for every operation before starting a new window.