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 U2FsdGVkX19J5UrkqyYcA5mMWH/ozXUNq1xemeGt05s=
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 02 10:37:47.070025 osdx systemd-journald[195106]: Runtime Journal (/run/log/journal/566e16bd7a954f06a36bb0e9b02f74c8) is 8.0M, max 77.8M, 69.8M free.
Jun 02 10:37:47.077228 osdx systemd-journald[195106]: Received client request to rotate journal, rotating.
Jun 02 10:37:47.077421 osdx systemd-journald[195106]: Vacuuming done, freed 0B of archived journals from /run/log/journal/566e16bd7a954f06a36bb0e9b02f74c8.
Jun 02 10:37:47.099510 osdx sudo[223335]: pam_limits(sudo:session): invalid line '@200:215        hard        maxlogins        ' - skipped
Jun 02 10:37:47.169032 osdx OSDxCLI[222013]: User 'admin' executed a new command: 'system journal clear'.
Jun 02 10:38:07.375064 osdx OSDxCLI[222013]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 02 10:38:07.575064 osdx OSDxCLI[222013]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 02 10:38:08.807064 osdx OSDxCLI[222013]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 02 10:38:10.027059 osdx OSDxCLI[222013]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 02 10:38:11.259113 osdx OSDxCLI[222013]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 02 10:38:12.495073 osdx OSDxCLI[222013]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 02 10:38:13.759076 osdx OSDxCLI[222013]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 02 10:38:15.011067 osdx OSDxCLI[222013]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 02 10:38:16.311111 osdx OSDxCLI[222013]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 02 10:38:17.416346 osdx wwan-module[223067]: [Core/cell0] Info: Signal '12' received to reconnect device.
Jun 02 10:38:17.416417 osdx wwan-module[223067]: [Device/cell0] Info: Stopping network connection...
Jun 02 10:38:17.435384 osdx wwan-module[223434]: Network cancelled... releasing resources
Jun 02 10:38:17.538916 osdx wwan-module[223434]: [/dev/cdc-wdm0] Network stopped
Jun 02 10:38:17.538916 osdx wwan-module[223434]: [/dev/cdc-wdm0] Client ID not released:
Jun 02 10:38:17.538916 osdx wwan-module[223434]:         Service: 'wds'
Jun 02 10:38:17.538916 osdx wwan-module[223434]:             CID: '21'
Jun 02 10:38:17.540722 osdx wwan-module[223067]: [Device/cell0] Info: Network connection was stopped!
Jun 02 10:38:17.542893 osdx wwan-module[223067]: [Network/cell0] Info: Stopping accessibility control...
Jun 02 10:38:17.543105 osdx wwan-module[223067]: [Network/cell0] Info: Accessibility control was stopped!
Jun 02 10:38:17.545840 osdx kernel: net cell0: link_state 0x1 -> 0x0
Jun 02 10:38:17.556798 osdx modulelauncher[223441]: stop DHCP client for cell0
Jun 02 10:38:17.558346 osdx dhclient[223154]: receive_packet failed on cell0: Network is down
Jun 02 10:38:17.560355 osdx wwan-module[223067]: [Device/cell0] Info: Checking registration state...
Jun 02 10:38:17.566943 osdx dhclient[223445]: Killed old client process
Jun 02 10:38:17.603143 osdx OSDxCLI[222013]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 02 10:38:17.666978 osdx wwan-module[223067]: [Device/cell0] Info: Device registered and PS attached successfully
Jun 02 10:38:17.666999 osdx wwan-module[223067]: [Device/cell0] Info: Establishing network connection...
Jun 02 10:38:17.706223 osdx dhclient[223445]: DHCPRELEASE of 2.143.54.90 on cell0 to 2.143.54.89 port 67
Jun 02 10:38:17.706252 osdx dhclient[223445]: send_packet: Network is down
Jun 02 10:38:17.706264 osdx dhclient[223445]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.
Jun 02 10:38:17.927911 osdx wwan-module[223067]: [Device/cell0] Info: Network connection was successfully started: PDH=[4159831552]
Jun 02 10:38:18.053792 osdx kernel: net cell0: link_state 0x0 -> 0x1
Jun 02 10:38:18.057446 osdx wwan-module[223067]: [Network/cell0] Info: Starting accessibility control...
Jun 02 10:38:18.057880 osdx wwan-module[223067]: [Network/cell0] Info: Accessibility control was started!
Jun 02 10:38:18.303085 osdx modulelauncher[223494]: start DHCP client for cell0
Jun 02 10:38:18.549808 osdx kernel: IPv6: ADDRCONF(NETDEV_CHANGE): cell0: link becomes ready