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 U2FsdGVkX18wO5zaHtgelqirEo4sonpwTghG9MP4j0g=
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

Oct 11 04:20:25.158680 osdx systemd-journald[149063]: Runtime Journal (/run/log/journal/a49dff1c004f48309a51b7b6c04ed558) is 4.8M, max 38.4M, 33.6M free.
Oct 11 04:20:25.163524 osdx systemd-journald[149063]: Received client request to rotate journal, rotating.
Oct 11 04:20:25.163724 osdx systemd-journald[149063]: Vacuuming done, freed 0B of archived journals from /run/log/journal/a49dff1c004f48309a51b7b6c04ed558.
Oct 11 04:20:25.254246 osdx OSDxCLI[769571]: User 'admin' executed a new command: 'system journal clear'.
Oct 11 04:20:45.432196 osdx OSDxCLI[769571]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 11 04:20:45.616205 osdx OSDxCLI[769571]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 11 04:20:46.816200 osdx OSDxCLI[769571]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 11 04:20:48.032149 osdx OSDxCLI[769571]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 11 04:20:49.244207 osdx OSDxCLI[769571]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 11 04:20:50.460212 osdx OSDxCLI[769571]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 11 04:20:51.696196 osdx OSDxCLI[769571]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 11 04:20:52.936201 osdx OSDxCLI[769571]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 11 04:20:54.200256 osdx OSDxCLI[769571]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 11 04:20:55.456213 osdx OSDxCLI[769571]: User 'admin' executed a new command: 'system journal show | cat'.
Oct 11 04:20:55.513811 osdx wwan-module[773123]: [Core/cell0] Info: Signal '12' received to reconnect device.
Oct 11 04:20:55.513855 osdx wwan-module[773123]: [Device/cell0] Info: Stopping network connection...
Oct 11 04:20:55.531927 osdx wwan-module[773730]: Network cancelled... releasing resources
Oct 11 04:20:55.668132 osdx wwan-module[773730]: [/dev/cdc-wdm0] Network stopped
Oct 11 04:20:55.668132 osdx wwan-module[773730]: [/dev/cdc-wdm0] Client ID not released:
Oct 11 04:20:55.668132 osdx wwan-module[773730]:         Service: 'wds'
Oct 11 04:20:55.668132 osdx wwan-module[773730]:             CID: '21'
Oct 11 04:20:55.669997 osdx wwan-module[773123]: [Device/cell0] Info: Network connection was stopped!
Oct 11 04:20:55.672223 osdx wwan-module[773123]: [Network/cell0] Info: Stopping accessibility control...
Oct 11 04:20:55.672449 osdx wwan-module[773123]: [Network/cell0] Info: Accessibility control was stopped!
Oct 11 04:20:55.674900 osdx kernel: net cell0: link_state 0x1 -> 0x0
Oct 11 04:20:55.686801 osdx modulelauncher[773737]: stop DHCP client for cell0
Oct 11 04:20:55.688692 osdx dhclient[773429]: receive_packet failed on cell0: Network is down
Oct 11 04:20:55.692002 osdx wwan-module[773123]: [Device/cell0] Info: Checking registration state...
Oct 11 04:20:55.698193 osdx dhclient[773741]: Killed old client process
Oct 11 04:20:55.796161 osdx wwan-module[773123]: [Device/cell0] Info: Device registered and PS attached successfully
Oct 11 04:20:55.796184 osdx wwan-module[773123]: [Device/cell0] Info: Establishing network connection...
Oct 11 04:20:55.823352 osdx dhclient[773741]: DHCPRELEASE of 5.205.236.57 on cell0 to 5.205.236.58 port 67
Oct 11 04:20:55.823381 osdx dhclient[773741]: send_packet: Network is down
Oct 11 04:20:55.823393 osdx dhclient[773741]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.
Oct 11 04:20:56.057016 osdx wwan-module[773123]: [Device/cell0] Info: Network connection was successfully started: PDH=[116478576]
Oct 11 04:20:56.182893 osdx kernel: net cell0: link_state 0x0 -> 0x1
Oct 11 04:20:56.184108 osdx wwan-module[773123]: [Network/cell0] Info: Starting accessibility control...
Oct 11 04:20:56.184383 osdx wwan-module[773123]: [Network/cell0] Info: Accessibility control was started!
Oct 11 04:20:56.425061 osdx modulelauncher[773790]: start DHCP client for cell0