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 U2FsdGVkX18TpyD+OWxKyJWyQD6ezfRzPvjbc7+R0pw=
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

Apr 06 19:18:16.813085 osdx systemd-journald[1891]: Runtime Journal (/run/log/journal/b9fcd2220c9647ce861546b33b7d6d22) is 8.0M, max 77.8M, 69.8M free.
Apr 06 19:18:16.820604 osdx systemd-journald[1891]: Received client request to rotate journal, rotating.
Apr 06 19:18:16.820808 osdx systemd-journald[1891]: Vacuuming done, freed 0B of archived journals from /run/log/journal/b9fcd2220c9647ce861546b33b7d6d22.
Apr 06 19:18:16.912346 osdx OSDxCLI[77389]: User 'admin' executed a new command: 'system journal clear'.
Apr 06 19:18:37.078317 osdx OSDxCLI[77389]: User 'admin' executed a new command: 'system journal show | cat'.
Apr 06 19:18:37.266366 osdx OSDxCLI[77389]: User 'admin' executed a new command: 'system journal show | cat'.
Apr 06 19:18:38.462357 osdx OSDxCLI[77389]: User 'admin' executed a new command: 'system journal show | cat'.
Apr 06 19:18:39.662356 osdx OSDxCLI[77389]: User 'admin' executed a new command: 'system journal show | cat'.
Apr 06 19:18:40.902356 osdx OSDxCLI[77389]: User 'admin' executed a new command: 'system journal show | cat'.
Apr 06 19:18:42.118378 osdx OSDxCLI[77389]: User 'admin' executed a new command: 'system journal show | cat'.
Apr 06 19:18:43.350360 osdx OSDxCLI[77389]: User 'admin' executed a new command: 'system journal show | cat'.
Apr 06 19:18:44.586380 osdx OSDxCLI[77389]: User 'admin' executed a new command: 'system journal show | cat'.
Apr 06 19:18:45.834406 osdx OSDxCLI[77389]: User 'admin' executed a new command: 'system journal show | cat'.
Apr 06 19:18:47.090458 osdx OSDxCLI[77389]: User 'admin' executed a new command: 'system journal show | cat'.
Apr 06 19:18:47.236772 osdx wwan-module[81812]: [Core/cell0] Info: Signal '12' received to reconnect device.
Apr 06 19:18:47.236816 osdx wwan-module[81812]: [Device/cell0] Info: Stopping network connection...
Apr 06 19:18:47.254738 osdx wwan-module[82433]: Network cancelled... releasing resources
Apr 06 19:18:47.358251 osdx wwan-module[82433]: [/dev/cdc-wdm0] Network stopped
Apr 06 19:18:47.358251 osdx wwan-module[82433]: [/dev/cdc-wdm0] Client ID not released:
Apr 06 19:18:47.358251 osdx wwan-module[82433]:         Service: 'wds'
Apr 06 19:18:47.358251 osdx wwan-module[82433]:             CID: '21'
Apr 06 19:18:47.359875 osdx wwan-module[81812]: [Device/cell0] Info: Network connection was stopped!
Apr 06 19:18:47.362051 osdx wwan-module[81812]: [Network/cell0] Info: Stopping accessibility control...
Apr 06 19:18:47.362312 osdx wwan-module[81812]: [Network/cell0] Info: Accessibility control was stopped!
Apr 06 19:18:47.367351 osdx kernel: net cell0: link_state 0x1 -> 0x0
Apr 06 19:18:47.376175 osdx modulelauncher[82441]: stop DHCP client for cell0
Apr 06 19:18:47.377249 osdx dhclient[82126]: receive_packet failed on cell0: Network is down
Apr 06 19:18:47.379316 osdx wwan-module[81812]: [Device/cell0] Info: Checking registration state...
Apr 06 19:18:47.386645 osdx dhclient[82445]: Killed old client process
Apr 06 19:18:47.486361 osdx wwan-module[81812]: [Device/cell0] Info: Device registered and PS attached successfully
Apr 06 19:18:47.486383 osdx wwan-module[81812]: [Device/cell0] Info: Establishing network connection...
Apr 06 19:18:47.517522 osdx dhclient[82445]: DHCPRELEASE of 5.205.209.94 on cell0 to 5.205.209.93 port 67
Apr 06 19:18:47.517551 osdx dhclient[82445]: send_packet: Network is down
Apr 06 19:18:47.517563 osdx dhclient[82445]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.
Apr 06 19:18:47.758068 osdx wwan-module[81812]: [Device/cell0] Info: Network connection was successfully started: PDH=[2175561024]
Apr 06 19:18:47.873075 osdx kernel: net cell0: link_state 0x0 -> 0x1
Apr 06 19:18:47.873719 osdx wwan-module[81812]: [Network/cell0] Info: Starting accessibility control...
Apr 06 19:18:47.874026 osdx wwan-module[81812]: [Network/cell0] Info: Accessibility control was started!
Apr 06 19:18:48.121544 osdx modulelauncher[82494]: start DHCP client for cell0