Well, After debugging, it is more likely to have some bug in my code because finally, it works after several scenario, but for some reason I don't understand so far, after a moment, the SGSN requests to delete the pdp context.
So, I was connected with a real sim card for around 1 minute, great!
But I still need a clarification about what to do about echo-response at GTP-U because I can only handle echo-response at GTP-C because my ggsn listen in 2123, but I cannot add any message at all like echo-response in 2152 because libgtpnl manage it.
Best Regards,
Le jeu. 20 août 2020 à 12:49, Papa Tana papa.tana101@gmail.com a écrit :
Hi,
After successfully making libgtpnl works between 02 Linux Host, now I am in the step of connecting one Linux Host to a real live SGSN this morning.
I don't have any particular issue at GTP-C side:
- the Mobile Station registered on 3G network, requests one activate PDP
context to the SGSN
- the SGSN sends to my ggsn a create PDP context
- my ggsn accepts it, and answers with all the needed information, such
as MS_Address, DNS Address 1, DNS address 2, IP of GGSN-C, IP of GGSN-U, TEID Control Plane, TEID user plane, .... everything should be OK.
- upon receipt of my creade_pdp_context_response accepted, the SGSN now
try to establish a Tunnel with the given TEID towards my GGSN
- but I cannot see anything on my GTPU-side in ggsn, apart of several
echo-request message from SGSN
- Sure, SGSN try to test connectivity to my ggsn GTPU by using
echo-request, but no response
- I don't know maybe because of no response, or because of SGSN alert me
with an error gtpu-sm-cause-update-ggsn-path-failure, the SGSN decide to send a delete request
So I have 02 questions please:
- At GTP-C, I can implement all messages(echo-response,
create-response, delete-response) but at GTPU-side, as the port is used by libgtpnl, I cannot implement an echo-response at all ==> So, do libgtpnl is supposed to answer or not to an echo-response received from a SGSN at GTPU-level?
- When I tried a Linux-to-Linux setup, it worked because I specified
the ms_addr and sgsn_addr in the 02 Linux Host. But as I cannot configure anything about the tunnel at SGSN-side(done automatically by SGSN), I can only create the tunnel at ggsn-side thanks to my user space program, by passing the TEID and ms_addr input to libgtpnl. Does it mean that libgtpnl only complies with OpenGGSN, ergw, and OpenAirInterface but not intended to ber used with a real SGSN?
Thanks for clarifying me, Best Regards,
Le lun. 10 août 2020 à 23:00, Harald Welte laforge@osmocom.org a écrit :
Hi Papa,
On Sat, Aug 08, 2020 at 10:59:24AM +0300, Papa Tana wrote:
It is working now. Very simple and stupid mistake from my side at network namespace
configuration.
I'm very happy to hear it's working successfully. Sometimes I start to doubt if there are problems in the codebase, but the fact that you report you got it to work is a relief in that regard :) --
- Harald Welte laforge@osmocom.org
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