Check Accessibility Control

This scenario shows how to configure a cellular interface, enabling the accessibility control mechanism that triggers reconnections when network connectivity is lost.

Test Reconnection By Accessibility Control

Description

In DUT0, the cell0 cellular interface is configured with a cellular profile for which accessibility control is enabled. Once connectivity with Google’s DNS public server has been verified, a situation where 100% of the packets received by the network are lost is emulated to verify that the accessibility control mechanism triggers a reconnection.

Scenario

Step 1: Set the following configuration in DUT0 :

set cellular logging level info
set cellular profile CELPROFILE accessibility-control ping address 8.8.8.8
set cellular profile CELPROFILE accessibility-control ping interval 10
set cellular profile CELPROFILE apn movistar.es
set interfaces cellular cell0 address dhcp
set interfaces cellular cell0 encrypted-pin U2FsdGVkX18YmrJ0Gya5WcgfknTWkjo22Xo832q3au4=
set interfaces cellular cell0 profile CELPROFILE
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Note

Once the cellular interface is configured, it can be verified that there is network connectivity by pinging Google’s DNS public server.

Step 2: Ping IP address 8.8.8.8 from DUT0:

admin@DUT0$ ping 8.8.8.8 count 1 size 56 timeout 1

Note

The accessibility control is a mechanism where pings are sent at an interval, and to the IP address, configured by the user. The mechanism then waits for a response within this interval. If no response is received before it times out, a second ping is sent and a response is expected within 10 seconds. If there is still no response, two more pings are sent at 5-second intervals. Finally, if there is still no response, the device reconnects to the network.

Note

As a result, you can verify that no reconnection has been recorded in the system logs if you wait long enough.

Step 3: Run command system journal clear at DUT0.

Step 4: Run command system journal show | cat at DUT0 and check if output does not contain the following tokens:

[Core/cell0] Info: Signal '12' received to reconnect device
[Device/cell0] Info: Stopping network connection
[Device/cell0] Info: Establishing network connection

Note

However, when traffic control is applied, it is possible to prove the ‘ping’ command is failing because ICMP packets are being dropped.

Step 5: Modify the following configuration lines in DUT0 :

set interfaces cellular cell0 traffic control in PLOSS
set traffic control PLOSS type network-emulator packet-loss 100

Step 6: Expect a failure in the following command: Ping IP address 8.8.8.8 from DUT0:

admin@DUT0$ ping 8.8.8.8 count 1 size 56 timeout 1

Note

You can verify that a reconnection has been recorded in the system logs if you wait long enough.

Step 7: Run command system journal clear at DUT0.

Step 8: Run command system journal show | cat at DUT0 and check if output does not contain the following tokens:

[Core/cell0] Info: Signal '12' received to reconnect device
[Device/cell0] Info: Stopping network connection
[Device/cell0] Info: Establishing network connection

Step 9: Run command system journal show | cat at DUT0 and check if output contains the following tokens:

[Core/cell0] Info: Signal '12' received to reconnect device
[Device/cell0] Info: Stopping network connection
[Device/cell0] Info: Establishing network connection

Show output

Jul 28 17:45:55.894649 osdx systemd-journald[391824]: Runtime Journal (/run/log/journal/d859f2b5fbb44052b1f1c2893eea0f68) is 1.0M, max 8.5M, 7.4M free.
Jul 28 17:45:55.896824 osdx systemd-journald[391824]: Received client request to rotate journal, rotating.
Jul 28 17:45:55.897022 osdx systemd-journald[391824]: Vacuuming done, freed 0B of archived journals from /run/log/journal/d859f2b5fbb44052b1f1c2893eea0f68.
Jul 28 17:45:55.918804 osdx sudo[685555]: pam_limits(sudo:session): invalid line '@200:215        hard        maxlogins        ' - skipped
Jul 28 17:45:55.986340 osdx OSDxCLI[682663]: User 'admin' executed a new command: 'system journal clear'.
Jul 28 17:46:01.200742 osdx CRON[685567]: pam_limits(cron:session): invalid line '@200:215        hard        maxlogins        ' - skipped
Jul 28 17:46:16.220239 osdx OSDxCLI[682663]: User 'admin' executed a new command: 'system journal show | cat'.
Jul 28 17:46:16.456240 osdx OSDxCLI[682663]: User 'admin' executed a new command: 'system journal show | cat'.
Jul 28 17:46:17.704241 osdx OSDxCLI[682663]: User 'admin' executed a new command: 'system journal show | cat'.
Jul 28 17:46:18.980231 osdx OSDxCLI[682663]: User 'admin' executed a new command: 'system journal show | cat'.
Jul 28 17:46:20.260239 osdx OSDxCLI[682663]: User 'admin' executed a new command: 'system journal show | cat'.
Jul 28 17:46:21.556250 osdx OSDxCLI[682663]: User 'admin' executed a new command: 'system journal show | cat'.
Jul 28 17:46:22.844236 osdx OSDxCLI[682663]: User 'admin' executed a new command: 'system journal show | cat'.
Jul 28 17:46:24.160177 osdx OSDxCLI[682663]: User 'admin' executed a new command: 'system journal show | cat'.
Jul 28 17:46:25.488267 osdx OSDxCLI[682663]: User 'admin' executed a new command: 'system journal show | cat'.
Jul 28 17:46:26.005239 osdx wwan-module[685288]: [Core/cell0] Info: Signal '12' received to reconnect device.
Jul 28 17:46:26.005286 osdx wwan-module[685288]: [Device/cell0] Info: Stopping network connection...
Jul 28 17:46:26.023450 osdx wwan-module[685651]: Network cancelled... releasing resources
Jul 28 17:46:26.159962 osdx wwan-module[685651]: [/dev/cdc-wdm0] Network stopped
Jul 28 17:46:26.159962 osdx wwan-module[685651]: [/dev/cdc-wdm0] Client ID not released:
Jul 28 17:46:26.159962 osdx wwan-module[685651]:         Service: 'wds'
Jul 28 17:46:26.159962 osdx wwan-module[685651]:             CID: '21'
Jul 28 17:46:26.161815 osdx wwan-module[685288]: [Device/cell0] Info: Network connection was stopped!
Jul 28 17:46:26.163925 osdx wwan-module[685288]: [Network/cell0] Info: Stopping accessibility control...
Jul 28 17:46:26.164488 osdx wwan-module[685288]: [Network/cell0] Info: Accessibility control was stopped!
Jul 28 17:46:26.166957 osdx kernel: net cell0: link_state 0x1 -> 0x0
Jul 28 17:46:26.177948 osdx modulelauncher[685658]: stop DHCP client for cell0
Jul 28 17:46:26.179192 osdx dhclient[685376]: receive_packet failed on cell0: Network is down
Jul 28 17:46:26.181284 osdx wwan-module[685288]: [Device/cell0] Info: Checking registration state...
Jul 28 17:46:26.188008 osdx dhclient[685662]: Killed old client process
Jul 28 17:46:26.288013 osdx wwan-module[685288]: [Device/cell0] Info: Device registered and PS attached successfully
Jul 28 17:46:26.288034 osdx wwan-module[685288]: [Device/cell0] Info: Establishing network connection...
Jul 28 17:46:26.327373 osdx dhclient[685662]: DHCPRELEASE of 5.205.214.80 on cell0 to 5.205.214.81 port 67
Jul 28 17:46:26.327402 osdx dhclient[685662]: send_packet: Network is down
Jul 28 17:46:26.327413 osdx dhclient[685662]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.