[WIP] No more ctx, call adl_gprsUnsubscribe()


#1

I’m running the WIP Sample “UDP Client” application with the only modifications being changes to the APN and socket address/port number plus I’ve added the local (source) port number as follows:

wip_debug( "[appli_entry_point] Creating UDP transmit socket\n" );
	tx_socket = wip_UDPCreateOpts( evh_udp_tx,
								   NULL,
								   WIP_COPT_PEER_STRADDR, SERVER_DATA_ADDR,
								   WIP_COPT_PEER_PORT, SERVER_DATA_PORT,
								   WIP_COPT_PORT, LOCAL_DATA_PORT,
								   WIP_COPT_END );

On execution of the application program, sometimes it establishes the bearer and everything works fine, but on other occasions I receive the message stream at the end of this post and the application effectively hangs (the latter is probably not too surprising since its very basic code with minimal error recovery).

I can’t find the message

documented anywhere, but maybe I’ve missed it?? What does does it mean in real terms - its obviously referring to something related to context?


#2

Hi,

From the log, PDP context was being deactivated by network.

As bearer was failed, so WIP returns that messages.
Can you check with operator why activation failed?

Can you query below and let us know the return?
AT+CGATT?
AT+CGACT?
AT+CEER
AT+CSQ
AT+CREG?
AT+CPIN?
This can help to understand the causes.
Thanks.


#3

Apologies for the delay in responding. As the problem is somewhat intermittent I haven’t yet been able to reproduce the issue for long enough. It does appear to be somewhat dependent on the time of day, with late afternoons being worse, but I haven’t been able to exhaustively prove that.

I believe what is happening is that the modem is changing cells. At one stage (about a month ago) I turned on notifications with an AT command and observed that cell-changing behaviour fairly frequently. We’re on the fringe of several cellular base stations although to counteract that I’m using a collinear antenna to provide some additional gain.

I do know that at the time the problems were occurring we were fully registered on the network with the GPRS bearer established. Signal levels reported by the AT+CSQ command are in the region of 7-8 normally. Unfortunately Vodafone NZ engineers are less than helpful in following up such issues and I’ve had the same lack of interest in support experience with that carrier some years ago.

So, until I manage to reproduce the problem for a reasonable length of time that’s all I have to go on at present.

One of my real concerns is that none of those internal WIP messages is documented anywhere. Its a bit like receiving unhandled exceptions - you don’t know what they are caused by!


#4

Louis,

It failed again so issued the requested commands, captured as follows::

“Open AT OS Package”,“6.35.0.201102280758”
-“Firmware Package”,“7.45.1.201105250600-2”
-“WIP Plug-in Package”,“5.41.0.201102280815”
“ROM”,“800000”
“RAM”,“200000”
“DWLNAME”,“FXT003”

OK

+WMFM: 0,2,1,1
+WMFM: 0,2,2,0
+WMFM: 0,2,3,1
+WMFM: 1,2,4,0
+WMFM: 1,2,4,1

OK

+WIND: 1

+WIND: 7

+WIND: 16

+WIND: 4

+WIND: 10,“SM”,0,“ON”,0,“SN”,0,“EN”,0

+WIND: 11,“0EA3585893A743754ADDF318B2081AFF”,“C326EE416F3C3EDF680B9660E8AD3428”,

OK

+WIND: 3

Serial Number AM1440007508103

OK

OK

Serial Number AM1440007508103

OK

OK

+WOPEN: 1

OK

+WIND: 1

+WIND: 7

+WIND: 4
[GPRS]: open: -> DISCONNECTED
[GPRS]: start: -> CONNECTING
[GPRS]: GPRS CTX (cid=1) found
[GPRS]: GPRS EVENT SETUP OK (cid=1): GPRS activate
[GPRS]: GPRS CTX (cid=1) found
[GPRS]: GPRS EVENT SETUP/ACTIVATE KO (cid=1): -> DISCONNECTED
[WIP] No more ctx, call adl_gprsUnsubscribe()
AT+CGATT?

+CGATT: 1

OK
AT+CGACT?

+CGACT: 1,0
+CGACT: 5,0

OK
AT+CEER

+CEER: Error 235

OK
AT+CSQ

+CSQ: 6,0

OK
AT+CREG?

+CREG: 0,1

OK
AT+CPIN?

+CPIN: READY


#5

+CEER: Error 235
-> unsuccessful activation, network reject
You may check with carrier why exactly being rejected…

+CSQ: 6,0
-> signal strength is too low, I think we should get >10 for reliable GPRS connection.


#6

I there some way that after getting this problem o every related to GPRS context, adl_gprsUnsubscribe() isn’t called?

It’s like you get in a basement or get inside of an elevator, you lost signal but your application needs to retry again minutes later. If I need to try again the only solution for me now is reset. What else can I do?


#7

I have had this problem in New Zealand where signal strength is low. That is the
“[WIP] No more ctx, call adl_gprsUnsubscribe()” error while activating a bearer. Any repeated attempts would also fail. The only solution I had was to reset (at+cfun=1) I have never liked such a drastic solution.
I have found that the problem occurs after a long period of inactivity (3-4hrs). I find now that instead of the total reset the same can be achieved by de-register (AT+COPS=2) re-register (AT+COPS=0).
I have an application which uploads every 6hrs, if the first attempt fails apply above and bearer activation happens straight off.(it seems with a much reduced time lag)