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/tCKBPRNpjYtZyg3/1M/XFtZ1+Y5bHnRU=
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

Feb 19 17:45:18.422860 osdx systemd-journald[1630]: Runtime Journal (/run/log/journal/cd1f9d843a4f4075b680db9f5427d594) is 1.0M, max 8.5M, 7.4M free.
Feb 19 17:45:18.425042 osdx systemd-journald[1630]: Received client request to rotate journal, rotating.
Feb 19 17:45:18.425240 osdx systemd-journald[1630]: Vacuuming done, freed 0B of archived journals from /run/log/journal/cd1f9d843a4f4075b680db9f5427d594.
Feb 19 17:45:18.512057 osdx OSDxCLI[60504]: User 'admin' executed a new command: 'system journal clear'.
Feb 19 17:45:38.705968 osdx OSDxCLI[60504]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 17:45:38.937970 osdx OSDxCLI[60504]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 17:45:40.201984 osdx OSDxCLI[60504]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 17:45:41.449995 osdx OSDxCLI[60504]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 17:45:42.741990 osdx OSDxCLI[60504]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 17:45:44.001987 osdx OSDxCLI[60504]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 17:45:45.262002 osdx OSDxCLI[60504]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 17:45:46.573983 osdx OSDxCLI[60504]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 17:45:47.750501 osdx wwan-module[61958]: [Core/cell0] Info: Signal '12' received to reconnect device.
Feb 19 17:45:47.750554 osdx wwan-module[61958]: [Device/cell0] Info: Stopping network connection...
Feb 19 17:45:47.768468 osdx wwan-module[62268]: Network cancelled... releasing resources
Feb 19 17:45:47.849948 osdx OSDxCLI[60504]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 17:45:48.217537 osdx wwan-module[62268]: [/dev/cdc-wdm0] Network stopped
Feb 19 17:45:48.217537 osdx wwan-module[62268]: [/dev/cdc-wdm0] Client ID not released:
Feb 19 17:45:48.217537 osdx wwan-module[62268]:         Service: 'wds'
Feb 19 17:45:48.217537 osdx wwan-module[62268]:             CID: '21'
Feb 19 17:45:48.219348 osdx wwan-module[61958]: [Device/cell0] Info: Network connection was stopped!
Feb 19 17:45:48.221419 osdx wwan-module[61958]: [Network/cell0] Info: Stopping accessibility control...
Feb 19 17:45:48.221986 osdx wwan-module[61958]: [Device/cell0] Info: Accessibility control was stopped!
Feb 19 17:45:48.224719 osdx kernel: net cell0: link_state 0x1 -> 0x0
Feb 19 17:45:48.234872 osdx modulelauncher[62275]: stop DHCP client for cell0
Feb 19 17:45:48.238364 osdx dhclient[62021]: receive_packet failed on cell0: Network is down
Feb 19 17:45:48.240045 osdx wwan-module[61958]: [Device/cell0] Info: Establishing network connection...
Feb 19 17:45:48.245124 osdx dhclient[62280]: Killed old client process
Feb 19 17:45:48.369010 osdx dhclient[62280]: DHCPRELEASE of 176.82.166.55 on cell0 to 176.82.166.56 port 67
Feb 19 17:45:48.369040 osdx dhclient[62280]: send_packet: Network is down
Feb 19 17:45:48.369052 osdx dhclient[62280]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.