Disconnect after successful registration

[acmileZZZ]

Issue Description

I deployed srsran in a virtual machine and used BladeRF to try to connect to my OnePlus phone. The sim card information in the phone has been added to user_db. When I tried to connect to the base station, the phone showed that the registration was successful, but I observed that the epc was stuck at [sending EMM information]. At this stage, the phone was able to access the Internet, but after a few seconds, the phone was disconnected from the base station.

Actual situation

--- Software Radio Systems EPC ---

Couldn't open , trying /root/.config/srsran/epc.conf
Reading configuration file /root/.config/srsran/epc.conf...
Couldn't open user_db.csv, trying /root/.config/srsran/user_db.csv
HSS Initialized.
MME S11 Initialized
MME GTP-C Initialized
MME Initialized. MCC: 0xf001, MNC: 0xff01
SPGW GTP-U Initialized.
SPGW S11 Initialized.
SP-GW Initialized.
Received S1 Setup Request.
S1 Setup Request - eNB Name: srsenb01, eNB id: 0x19b
S1 Setup Request - MCC:001, MNC:01
S1 Setup Request - TAC 7, B-PLMN 0xf110
S1 Setup Request - Paging DRX v128
Sending S1 Setup Response
Initial UE message: LIBLTE_MME_MSG_TYPE_ATTACH_REQUEST
Received Initial UE message -- Attach Request
Attach request -- IMSI: 001012000100861
Attach request -- eNB-UE S1AP Id: 1
Attach request -- Attach type: 2
Attach Request -- UE Network Capabilities EEA: 11110000
Attach Request -- UE Network Capabilities EIA: 01110000
Attach Request -- MS Network Capabilities Present: true
PDN Connectivity Request -- EPS Bearer Identity requested: 0
PDN Connectivity Request -- Procedure Transaction Id: 3
PDN Connectivity Request -- ESM Information Transfer requested: true
Downlink NAS: Sending Authentication Request
UL NAS: Received Authentication Response
Authentication Response -- IMSI 001012000100861
UE Authentication Accepted.
Generating KeNB with UL NAS COUNT: 0
Downlink NAS: Sending NAS Security Mode Command.
UL NAS: Received Security Mode Complete
Security Mode Command Complete -- IMSI: 001012000100861
Sending ESM information request
UL NAS: Received ESM Information Response
ESM Info: APN srsapn
Getting subscription information -- QCI 7
Sending Create Session Request.
Creating Session Response -- IMSI: 1012000100861
Creating Session Response -- MME control TEID: 1
Received GTP-C PDU. Message type: GTPC_MSG_TYPE_CREATE_SESSION_REQUEST
SPGW: Allocated Ctrl TEID 1
SPGW: Allocated User TEID 1
SPGW: Allocate UE IP 172.16.0.2
Received Create Session Response
Create Session Response -- SPGW control TEID 1
Create Session Response -- SPGW S1-U Address: 127.0.1.100
SPGW Allocated IP 172.16.0.2 to IMSI 001012000100861
Adding attach accept to Initial Context Setup Request
Sent Initial Context Setup Request. E-RAB id 5
Received Initial Context Setup Response
E-RAB Context Setup. E-RAB id 5
E-RAB Context -- eNB TEID 0x1; eNB GTP-U Address 127.0.1.1
Initial UE message: LIBLTE_MME_MSG_TYPE_ATTACH_REQUEST
Received Initial UE message -- Attach Request
Attach request -- M-TMSI: 0x352eb378
Attach request -- eNB-UE S1AP Id: 2
Attach request -- Attach type: 2
Attach Request -- UE Network Capabilities EEA: 11110000
Attach Request -- UE Network Capabilities EIA: 01110000
Attach Request -- MS Network Capabilities Present: true
PDN Connectivity Request -- EPS Bearer Identity requested: 0
PDN Connectivity Request -- Procedure Transaction Id: 4
PDN Connectivity Request -- ESM Information Transfer requested: true
Attach Request -- Found previously attach UE.
Found UE context. IMSI: 001012000100861, old eNB UE S1ap Id 1, old MME UE S1AP Id 1
GUTI Attach -- NAS Integrity OK. UL count 3, DL count 2
Generating KeNB with UL NAS COUNT: 3
Secure ESM information transfer requested.
UL NAS: Received ESM Information Response
ESM Info: APN srsapn
Getting subscription information -- QCI 7
Sending Create Session Request.
Creating Session Response -- IMSI: 1012000100861
Creating Session Response -- MME control TEID: 2
Received GTP-C PDU. Message type: GTPC_MSG_TYPE_CREATE_SESSION_REQUEST
SPGW: GTP-C context for IMSI 001012000100861 already exists.
SPGW: Deleted previous context.
SPGW: Allocated Ctrl TEID 2
SPGW: Allocated User TEID 2
SPGW: Allocate UE IP 172.16.0.3
Received Create Session Response
Create Session Response -- SPGW control TEID 2
Create Session Response -- SPGW S1-U Address: 127.0.1.100
SPGW Allocated IP 172.16.0.3 to IMSI 001012000100861
Adding attach accept to Initial Context Setup Request
Sent Initial Context Setup Request. E-RAB id 5
Received Initial Context Setup Response
E-RAB Context Setup. E-RAB id 5
E-RAB Context -- eNB TEID 0x2; eNB GTP-U Address 127.0.1.1
UL NAS: Received Attach Complete
Unpacked Attached Complete Message. IMSI 1012000100861
Unpacked Activate Default EPS Bearer message. EPS Bearer id 5
Received GTP-C PDU. Message type: GTPC_MSG_TYPE_MODIFY_BEARER_REQUEST
Sending EMM Information
Received UE Context Release Request. MME-UE S1AP Id 2
There are active E-RABs, send release access bearers request
Received UE Context Release Complete. MME-UE S1AP Id 2
UE Context Release Completed.
Received GTP-C PDU. Message type: GTPC_MSG_TYPE_RELEASE_ACCESS_BEARERS_REQUEST
Found UE for Downlink Notification
MME Ctr TEID 0x2, IMSI: 001012000100861
T3413 expired -- Could not page the ue.
Received GTP-C PDU. Message type: GTPC_MSG_TYPE_DOWNLINK_DATA_NOTIFICATION_FAILURE_INDICATION

Configuration

enb.conf
[enb]
enb_id = 0x19B
mcc = 001
mnc = 01
mme_addr = 127.0.1.100
gtp_bind_addr = 127.0.1.1
s1c_bind_addr = 127.0.1.1
s1c_bind_port = 0
n_prb = 50
tm = 3
nof_ports = 2

epc.conf
[mme]
mme_code = 0x1a
mme_group = 0x0001
tac = 0x0007
mcc = 001
mnc = 01
mme_bind_addr = 127.0.1.100
apn = srsapn
dns_addr = 8.8.8.8
encryption_algo = EEA0
integrity_algo = EIA1
paging_timer = 2
request_imeisv = false
lac = 0x0006