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 U2FsdGVkX1+Gr7+CzaIdq5zs6CYg25Gi4d7fbrLtqRg=
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

Jun 24 13:24:19.571137 osdx systemd-journald[1695]: Runtime Journal (/run/log/journal/748d2453e475484fa37ba4d4c4907ad2) is 1.0M, max 8.5M, 7.5M free.
Jun 24 13:24:19.573265 osdx systemd-journald[1695]: Received client request to rotate journal, rotating.
Jun 24 13:24:19.573465 osdx systemd-journald[1695]: Vacuuming done, freed 0B of archived journals from /run/log/journal/748d2453e475484fa37ba4d4c4907ad2.
Jun 24 13:24:19.663387 osdx OSDxCLI[92508]: User 'admin' executed a new command: 'system journal clear'.
Jun 24 13:24:39.833386 osdx OSDxCLI[92508]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 24 13:24:40.049392 osdx OSDxCLI[92508]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 24 13:24:41.245414 osdx OSDxCLI[92508]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 24 13:24:42.457401 osdx OSDxCLI[92508]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 24 13:24:43.669416 osdx OSDxCLI[92508]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 24 13:24:44.905409 osdx OSDxCLI[92508]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 24 13:24:46.161400 osdx OSDxCLI[92508]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 24 13:24:47.405404 osdx OSDxCLI[92508]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 24 13:24:48.414159 osdx wwan-module[94375]: [Core/cell0] Info: Signal '12' received to reconnect device.
Jun 24 13:24:48.414226 osdx wwan-module[94375]: [Device/cell0] Info: Stopping network connection...
Jun 24 13:24:48.433609 osdx wwan-module[94777]: Network cancelled... releasing resources
Jun 24 13:24:48.537352 osdx wwan-module[94777]: [/dev/cdc-wdm0] Network stopped
Jun 24 13:24:48.537352 osdx wwan-module[94777]: [/dev/cdc-wdm0] Client ID not released:
Jun 24 13:24:48.537352 osdx wwan-module[94777]:         Service: 'wds'
Jun 24 13:24:48.537352 osdx wwan-module[94777]:             CID: '21'
Jun 24 13:24:48.539659 osdx wwan-module[94375]: [Device/cell0] Info: Network connection was stopped!
Jun 24 13:24:48.541976 osdx wwan-module[94375]: [Network/cell0] Info: Stopping accessibility control...
Jun 24 13:24:48.542508 osdx wwan-module[94375]: [Network/cell0] Info: Accessibility control was stopped!
Jun 24 13:24:48.544125 osdx kernel: net cell0: link_state 0x1 -> 0x0
Jun 24 13:24:48.555773 osdx modulelauncher[94791]: stop DHCP client for cell0
Jun 24 13:24:48.556778 osdx dhclient[94483]: receive_packet failed on cell0: Network is down
Jun 24 13:24:48.560597 osdx wwan-module[94375]: [Device/cell0] Info: Checking registration state...
Jun 24 13:24:48.565785 osdx dhclient[94795]: Killed old client process
Jun 24 13:24:48.665398 osdx wwan-module[94375]: [Device/cell0] Info: Device registered and PS attached successfully
Jun 24 13:24:48.665422 osdx wwan-module[94375]: [Device/cell0] Info: Establishing network connection...
Jun 24 13:24:48.688612 osdx dhclient[94795]: DHCPRELEASE of 2.143.60.105 on cell0 to 2.143.60.106 port 67
Jun 24 13:24:48.688646 osdx dhclient[94795]: send_packet: Network is down
Jun 24 13:24:48.688657 osdx dhclient[94795]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.
Jun 24 13:24:48.697768 osdx OSDxCLI[92508]: User 'admin' executed a new command: 'system journal show | cat'.