Project

General

Profile

Open5GS-Traces » History » Version 19

jolly, 01/30/2024 10:33 AM

1 1 jolly
h1. Open5GS-Traces
2
3 16 jolly
p{background:red}. *!This is Work-In-Progress!*
4 5 jolly
5 8 jolly
h2. Setup of this example
6
7
* Ericsson RBS 6402 (eNodeB)
8
* Open5GS (4G network elements)
9
* OsmoHLR with OsmoDia2GSUP (HSS)
10
* OsmoMSC (SMS)
11
12 17 jolly
13 8 jolly
h2. Idle
14 1 jolly
15 10 jolly
When all phones are Idle, one will see the following trace with Wireshark on the link between eNodeB (Ericsson RBS) and MME (Open5GS).
16 1 jolly
17 15 jolly
p{border: solid 1px}. !wireshark_enb_idle.png!
18 8 jolly
19
The eNodeB (IP 10.0.15.117) is connected to MME (IP 10.0.15.1) via SCTP. Also the eNodeB syncs its clock to NTP server (IP 10.0.15.1).
20 19 jolly
21 9 jolly
The network 10.0.15.0/24 is the RAN network in this example.
22
23 17 jolly
24 9 jolly
h2. 4G Attachment
25
26 10 jolly
p{border: solid 1px}. !wireshark_enb_attach.png!
27 16 jolly
28 18 jolly
A 4G phone is attached to the network, using SIM cards that is registered in the HSS. The APN name used is "internet".
29 19 jolly
30 12 jolly
Lets go into detail:
31
32 17 jolly
33 12 jolly
h3. Attach request
34 1 jolly
35
p{border: solid 1px}. !wireshark_enb_attach_attach_request.png!
36 17 jolly
37 18 jolly
The UE sends an "Attach request". It is the message type of the "NAS-PDU" information element of the "initiatingMessage". The "NAS-PDU" message type is highlighted blue in the picture above.
38 19 jolly
39 17 jolly
Also within the "NAS-PDU" is the "EPS mobile identity". In this case the UE has the mobile country code "999" and the mobile network code "10". The IMSI is not shown. Because the UE was attached before, a TMSI is used. 
40 1 jolly
41
42
h3. ESM information request
43 17 jolly
44 1 jolly
p{border: solid 1px}. !wireshark_enb_attach_ESM_infomation_request.png!
45 14 jolly
46 18 jolly
The MME sends an "ESM information request" to the UE, to request APN name. The "NAS-PDU" message type is highlighted blue in the picture above.
47
 
48
49 1 jolly
h3. ESM information response
50 14 jolly
51 16 jolly
p{border: solid 1px}. !wireshark_enb_attach_ESM_infomation_response.png!
52 18 jolly
53
The UE send an "ESM information response." The UE uses the APN name "internet". The "NAS-PDU" message type is highlighted blue in the picture above.
54 19 jolly
55 18 jolly
This is the default configuration in the example setup. It can be configured in the configuration file for OsmoHLR. (osmo-hlr.cfg)
56
57 14 jolly
58
h3. Attach accept
59
60 16 jolly
p{border: solid 1px}. !wireshark_enb_attach_attach_accept.png!
61 14 jolly
62
h3. Attach complete
63
64 16 jolly
p{border: solid 1px}. !wireshark_enb_attach_attach_complete.png!
65 14 jolly
66
67 10 jolly
h2. 4G Detachment
68
69 1 jolly
The 4G phone is turned off or the airplane mode is turned on.
70 10 jolly
71 16 jolly
p{border: solid 1px}. !wireshark_enb_detach.png!
72 14 jolly
73
Lets go into detail:
74
75
h.3 Detach Reqeust
76
77 16 jolly
p{border: solid 1px}. !wireshark_enb_detach_detach_request.png!
78 14 jolly
79
h.3 UE context release
Add picture from clipboard (Maximum size: 48.8 MB)