How OCSG handle throttle exception

 hi,

Please note my SMSC config

Host Originated Traffic:

Windows Size = 10
Throughput = 50 messages / sec

OCSG Config:

Single instance of smpp plugin

1 Transmitter, 2 Receivers

Request timeout = 20 secs

Window size = -1

Now when i started bombarding messages to OCSG, i sporadically got network error / service exception:

Submit failed: Request timed out.

I changed in OCSG config: Request Timeout = 60 secs

Again bombarded, and then got, sporadically, following network  error:

System error

I changed in OCSG config: window size  = 10

Again bombarded and then got sporadically, the error:

Failed to submit message : Throttling error (ESME has exceeded allowed message limits)

Please help me understand how OCSG handles SMSC throttling, throughput constraints etc.