WIP_CEV_WRITE not firing when filling TCP send buffer

Legacy Open AT
1

Hi, I am trying to send out 20k plus worth of data over a client TCP connection.

Sending anything under the original 5840 buffer limit works no problem. I even increased that to 10k for other tests. Essentially as long as I send data out that is less than the buffer limit, then all is OK.

However I need to send large buffers out and have followed the documentation in that I use wip_write and if the result is less than then data I want to send, I wait for a WIP_CEV_WRITE event. However that event never gets fired. So I periodically tested for NWRITE parameter using wip_getOpts and am tracing it. One can clearly see that the send buffer is slowly being emptied until it is completely empty, but WIP_CEV_WRITE never gets fired. Additionally the SND_LOWAT is at a sensible limit of 1024, which is the point at which I expect to see the WIP_CEV_WRITE event to be fired.

Below is my trace, the first WIP_CEV_WRITE is fired as the channel is opened, but not later. The last trace repeats for a minute after which time I timeout and close the socket.

Does anyone have similar experiences or suggestions? I will now try and send the next lot based on the NWRITE value just to see if that works, however that feels like a cludge.

PS. I am using an FXT009 modem with the latest firmware (7.52) and version of Dev Studio (3.1)
Thanks,

Karl

12:04:17	1	ADL	2	WEB: Connecting to …...:12345: Result 403775832
12:04:17	1	ADL	2	WEB: Waiting for socket connection for Job103
12:04:18	1	ADL	2	WEB: WIPHandler 2
12:04:18	1	ADL	2	GetOpts: 0, KEEPALIVE: 0, SND_BUFSIZE: 5840,RCV_BUFSIZE: 5840,SND_LOWAT: 1024,RCV_LOWAT: 1, NREAD: 0, 
                                      NWRITE: 5840, NODELAY: 0,MAXSEG: 1380,TOS: 0,TTL: 64,REXMT_MAX: 10,REXMT_MAXCNT: 3
12:04:18	2	ADL	2	WEB: Socket open and options set 0
12:04:18	3	ADL	2	WEB: Socket connected to host
12:04:18	2	ADL	2	WEB: WIPHandler 6
12:04:18	1	ADL	2	WEB: WIP_CEV_WRITE       <=== Here the WIP_CEV_WRITE event is fired because the channel has just been opened.
12:04:18	2	ADL	2	WEB: Nothing to send
12:04:18	1	ADL	2	WEB: Trying connect to ……
12:04:18	1	ADL	2	WEB TX: 24074 bytes to host
12:04:18	1	ADL	2	GetOpts: 0, KEEPALIVE: 0, SND_BUFSIZE: 10240,RCV_BUFSIZE: 5840,SND_LOWAT: 1024,RCV_LOWAT: 1, NREAD: 0,
                                       NWRITE: 10240, NODELAY: 0,MAXSEG: 1380,TOS: 0,TTL: 64,REXMT_MAX: 10,REXMT_MAXCNT: 3
12:04:18	2	ADL	2	WEB: Partial write completed.. 10240bytes
12:04:19	1	ADL	2	GetOpts: 0, KEEPALIVE: 403705344, SND_BUFSIZE: 10240,RCV_BUFSIZE: 5840,SND_LOWAT: 1024,RCV_LOWAT: 1, NREAD: 14, 
                                      NWRITE: 0, NODELAY: 0,MAXSEG: 1380,TOS: 0,TTL: 64,REXMT_MAX: 10,REXMT_MAXCNT: 3
12:04:20	1	ADL	2	GetOpts: 0, KEEPALIVE: 403705344, SND_BUFSIZE: 10240,RCV_BUFSIZE: 5840,SND_LOWAT: 1024,RCV_LOWAT: 1, NREAD: 14, 
                                      NWRITE: 0, NODELAY: 0,MAXSEG: 1380,TOS: 0,TTL: 64,REXMT_MAX: 10,REXMT_MAXCNT: 3
12:04:21	1	ADL	2	GetOpts: 0, KEEPALIVE: 403705344, SND_BUFSIZE: 10240,RCV_BUFSIZE: 5840,SND_LOWAT: 1024,RCV_LOWAT: 1, NREAD: 14,
                                       NWRITE: 1368, NODELAY: 0,MAXSEG: 1380,TOS: 0,TTL: 64,REXMT_MAX: 10,REXMT_MAXCNT: 3
12:04:22	1	ADL	2	GetOpts: 0, KEEPALIVE: 403705344, SND_BUFSIZE: 10240,RCV_BUFSIZE: 5840,SND_LOWAT: 1024,RCV_LOWAT: 1, NREAD: 14, 
                                      NWRITE: 2736, NODELAY: 0,MAXSEG: 1380,TOS: 0,TTL: 64,REXMT_MAX: 10,REXMT_MAXCNT: 3
12:04:23	1	ADL	2	GetOpts: 0, KEEPALIVE: 403705344, SND_BUFSIZE: 10240,RCV_BUFSIZE: 5840,SND_LOWAT: 1024,RCV_LOWAT: 1, NREAD: 14, 
                                      NWRITE: 2736, NODELAY: 0,MAXSEG: 1380,TOS: 0,TTL: 64,REXMT_MAX: 10,REXMT_MAXCNT: 3
12:04:24	1	ADL	2	GetOpts: 0, KEEPALIVE: 403705344, SND_BUFSIZE: 10240,RCV_BUFSIZE: 5840,SND_LOWAT: 1024,RCV_LOWAT: 1, NREAD: 14,
                                       NWRITE: 4380, NODELAY: 0,MAXSEG: 1380,TOS: 0,TTL: 64,REXMT_MAX: 10,REXMT_MAXCNT: 3
12:04:25	1	ADL	2	GetOpts: 0, KEEPALIVE: 403705344, SND_BUFSIZE: 10240,RCV_BUFSIZE: 5840,SND_LOWAT: 1024,RCV_LOWAT: 1, NREAD: 14, 
                                      NWRITE: 5748, NODELAY: 0,MAXSEG: 1380,TOS: 0,TTL: 64,REXMT_MAX: 10,REXMT_MAXCNT: 3
12:04:26	1	ADL	2	GetOpts: 0, KEEPALIVE: 403705344, SND_BUFSIZE: 10240,RCV_BUFSIZE: 5840,SND_LOWAT: 1024,RCV_LOWAT: 1, NREAD: 14, 
                                      NWRITE: 5748, NODELAY: 0,MAXSEG: 1380,TOS: 0,TTL: 64,REXMT_MAX: 10,REXMT_MAXCNT: 3
12:04:27	1	ADL	2	GetOpts: 0, KEEPALIVE: 403705344, SND_BUFSIZE: 10240,RCV_BUFSIZE: 5840,SND_LOWAT: 1024,RCV_LOWAT: 1, NREAD: 14, 
                                      NWRITE: 7128, NODELAY: 0,MAXSEG: 1380,TOS: 0,TTL: 64,REXMT_MAX: 10,REXMT_MAXCNT: 3
12:04:28	1	ADL	2	GetOpts: 0, KEEPALIVE: 403705344, SND_BUFSIZE: 10240,RCV_BUFSIZE: 5840,SND_LOWAT: 1024,RCV_LOWAT: 1, NREAD: 14, 
                                      NWRITE: 8496, NODELAY: 0,MAXSEG: 1380,TOS: 0,TTL: 64,REXMT_MAX: 10,REXMT_MAXCNT: 3
12:04:29	1	ADL	2	GetOpts: 0, KEEPALIVE: 403705344, SND_BUFSIZE: 10240,RCV_BUFSIZE: 5840,SND_LOWAT: 1024,RCV_LOWAT: 1, NREAD: 14, 
                                      NWRITE: 9864, NODELAY: 0,MAXSEG: 1380,TOS: 0,TTL: 64,REXMT_MAX: 10,REXMT_MAXCNT: 3
12:04:30	1	ADL	2	GetOpts: 0, KEEPALIVE: 403705344, SND_BUFSIZE: 10240,RCV_BUFSIZE: 5840,SND_LOWAT: 1024,RCV_LOWAT: 1, NREAD: 14, 
                                      NWRITE: 10240, NODELAY: 0,MAXSEG: 1380,TOS: 0,TTL: 64,REXMT_MAX: 10,REXMT_MAXCNT: 3

 <=== The above line continues for 1min, but where is the WIP_CEV_WRITE event?
2

send buffer is slowly being emptied?? do u mean SND_BUFSIZE?

3

Hi Rex_alex, thanks for the reply. No I mean NWRITE, which according to the documentation is the

.

SND_BUFFER according the docs is the

So in the traces you can see NWRITE increasing from 0 up to 10240 (after the partial write). So I expect to get a CEV_WRITE event when NWRITE grows beyond 1024 which is the SND_LOWAT value which according to the docs is

Thanks,

Karl

4

sorry for being late… i tried with normla tcp application… i could see write event coming again…
you are facing this issue in specific FW ? didi u try with a simple tcp application…?
i guess i need to try out with your application if the issue is really there…