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+Qz341k4xAL3ROxCSn5d1fMAglXYh4UOI=
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 23 08:33:24.710842 osdx systemd-journald[1646]: Runtime Journal (/run/log/journal/a23b2afac92541ea8e63508150e36b75) is 1.0M, max 8.5M, 7.4M free.
Jun 23 08:33:24.713007 osdx systemd-journald[1646]: Received client request to rotate journal, rotating.
Jun 23 08:33:24.713205 osdx systemd-journald[1646]: Vacuuming done, freed 0B of archived journals from /run/log/journal/a23b2afac92541ea8e63508150e36b75.
Jun 23 08:33:24.799387 osdx OSDxCLI[3934]: User 'admin' executed a new command: 'system journal clear'.
Jun 23 08:33:44.985344 osdx OSDxCLI[3934]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 23 08:33:45.197375 osdx OSDxCLI[3934]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 23 08:33:46.417349 osdx OSDxCLI[3934]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 23 08:33:47.629340 osdx OSDxCLI[3934]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 23 08:33:48.841344 osdx OSDxCLI[3934]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 23 08:33:50.077347 osdx OSDxCLI[3934]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 23 08:33:51.305423 osdx OSDxCLI[3934]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 23 08:33:52.553367 osdx OSDxCLI[3934]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 23 08:33:53.821357 osdx OSDxCLI[3934]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 23 08:33:54.376733 osdx wwan-module[57428]: [Core/cell0] Info: Signal '12' received to reconnect device.
Jun 23 08:33:54.376815 osdx wwan-module[57428]: [Device/cell0] Info: Stopping network connection...
Jun 23 08:33:54.395059 osdx wwan-module[57735]: Network cancelled... releasing resources
Jun 23 08:33:54.429015 osdx wwan-module[57735]: [/dev/cdc-wdm0] Network stopped
Jun 23 08:33:54.429015 osdx wwan-module[57735]: [/dev/cdc-wdm0] Client ID not released:
Jun 23 08:33:54.429015 osdx wwan-module[57735]:         Service: 'wds'
Jun 23 08:33:54.429015 osdx wwan-module[57735]:             CID: '21'
Jun 23 08:33:54.430879 osdx wwan-module[57428]: [Device/cell0] Info: Network connection was stopped!
Jun 23 08:33:54.432983 osdx wwan-module[57428]: [Network/cell0] Info: Stopping accessibility control...
Jun 23 08:33:54.433541 osdx wwan-module[57428]: [Device/cell0] Info: Accessibility control was stopped!
Jun 23 08:33:54.436307 osdx kernel: net cell0: link_state 0x1 -> 0x0
Jun 23 08:33:54.445395 osdx modulelauncher[57741]: stop DHCP client for cell0
Jun 23 08:33:54.449242 osdx dhclient[57490]: receive_packet failed on cell0: Network is down
Jun 23 08:33:54.451328 osdx wwan-module[57428]: [Device/cell0] Info: Establishing network connection...
Jun 23 08:33:54.455772 osdx dhclient[57746]: Killed old client process
Jun 23 08:33:54.561752 osdx wwan-module[57428]: [Device/cell0] Info: Network connection was successfully started: PDH=[3681577168]
Jun 23 08:33:54.564063 osdx kernel: net cell0: link_state 0x0 -> 0x1
Jun 23 08:33:54.565709 osdx wwan-module[57428]: [Network/cell0] Info: Starting accessibility control...
Jun 23 08:33:54.565980 osdx wwan-module[57428]: [Network/cell0] Info: Accessibility control was started!
Jun 23 08:33:54.580487 osdx dhclient[57746]: DHCPRELEASE of 5.205.127.211 on cell0 to 5.205.127.212 port 67
Jun 23 08:33:54.580515 osdx dhclient[57746]: send_packet: Network is down
Jun 23 08:33:54.580526 osdx dhclient[57746]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.