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 U2FsdGVkX19v2VCG0XWfUs8faHVixPvlPcm79w+Y4zY=
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

Oct 20 20:15:22.147719 osdx systemd-journald[494915]: Runtime Journal (/run/log/journal/797c96fe414946a7bc327621253522b0) is 4.8M, max 38.4M, 33.6M free.
Oct 20 20:15:22.152624 osdx systemd-journald[494915]: Received client request to rotate journal, rotating.
Oct 20 20:15:22.152820 osdx systemd-journald[494915]: Vacuuming done, freed 0B of archived journals from /run/log/journal/797c96fe414946a7bc327621253522b0.
Oct 20 20:15:22.240651 osdx OSDxCLI[593214]: User 'admin' executed a new command: 'system journal clear'.
Oct 20 20:15:42.414621 osdx OSDxCLI[593214]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 20 20:15:42.618627 osdx OSDxCLI[593214]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 20 20:15:43.822632 osdx OSDxCLI[593214]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 20 20:15:45.042628 osdx OSDxCLI[593214]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 20 20:15:46.258638 osdx OSDxCLI[593214]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 20 20:15:47.490651 osdx OSDxCLI[593214]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 20 20:15:48.722665 osdx OSDxCLI[593214]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 20 20:15:49.966719 osdx OSDxCLI[593214]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 20 20:15:51.234666 osdx OSDxCLI[593214]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 20 20:15:52.510633 osdx OSDxCLI[593214]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 20 20:15:52.794757 osdx wwan-module[595068]: [Core/cell0] Info: Signal '12' received to reconnect device.
Oct 20 20:15:52.794803 osdx wwan-module[595068]: [Device/cell0] Info: Stopping network connection...
Oct 20 20:15:52.812762 osdx wwan-module[595480]: Network cancelled... releasing resources
Oct 20 20:15:52.918210 osdx wwan-module[595480]: [/dev/cdc-wdm0] Network stopped
Oct 20 20:15:52.918210 osdx wwan-module[595480]: [/dev/cdc-wdm0] Client ID not released:
Oct 20 20:15:52.918210 osdx wwan-module[595480]:         Service: 'wds'
Oct 20 20:15:52.918210 osdx wwan-module[595480]:             CID: '21'
Oct 20 20:15:52.920002 osdx wwan-module[595068]: [Device/cell0] Info: Network connection was stopped!
Oct 20 20:15:52.922138 osdx wwan-module[595068]: [Network/cell0] Info: Stopping accessibility control...
Oct 20 20:15:52.922366 osdx wwan-module[595068]: [Network/cell0] Info: Accessibility control was stopped!
Oct 20 20:15:52.925353 osdx kernel: net cell0: link_state 0x1 -> 0x0
Oct 20 20:15:52.936517 osdx modulelauncher[595487]: stop DHCP client for cell0
Oct 20 20:15:52.938038 osdx dhclient[595180]: receive_packet failed on cell0: Network is down
Oct 20 20:15:52.940033 osdx wwan-module[595068]: [Device/cell0] Info: Checking registration state...
Oct 20 20:15:52.946635 osdx dhclient[595491]: Killed old client process
Oct 20 20:15:53.046489 osdx wwan-module[595068]: [Device/cell0] Info: Device registered and PS attached successfully
Oct 20 20:15:53.046511 osdx wwan-module[595068]: [Device/cell0] Info: Establishing network connection...
Oct 20 20:15:53.085883 osdx dhclient[595491]: DHCPRELEASE of 5.205.191.253 on cell0 to 5.205.191.254 port 67
Oct 20 20:15:53.085914 osdx dhclient[595491]: send_packet: Network is down
Oct 20 20:15:53.085927 osdx dhclient[595491]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.
Oct 20 20:15:53.346875 osdx wwan-module[595068]: [Device/cell0] Info: Network connection was successfully started: PDH=[2175533904]
Oct 20 20:15:53.465364 osdx kernel: net cell0: link_state 0x0 -> 0x1
Oct 20 20:15:53.465791 osdx wwan-module[595068]: [Network/cell0] Info: Starting accessibility control...
Oct 20 20:15:53.466127 osdx wwan-module[595068]: [Network/cell0] Info: Accessibility control was started!
Oct 20 20:15:53.665860 osdx modulelauncher[595540]: start DHCP client for cell0