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/jawzuxNe51z1wnQmfG5Mui7P9IPz7y0w=
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

Aug 20 19:17:20.993201 osdx systemd-journald[158450]: Runtime Journal (/run/log/journal/548b181401aa4ff2bebbdfa57a5803f3) is 1.0M, max 8.5M, 7.4M free.
Aug 20 19:17:20.995351 osdx systemd-journald[158450]: Received client request to rotate journal, rotating.
Aug 20 19:17:20.995545 osdx systemd-journald[158450]: Vacuuming done, freed 0B of archived journals from /run/log/journal/548b181401aa4ff2bebbdfa57a5803f3.
Aug 20 19:17:21.017772 osdx sudo[717130]: pam_limits(sudo:session): invalid line '@200:215        hard        maxlogins        ' - skipped
Aug 20 19:17:21.084987 osdx OSDxCLI[712756]: User 'admin' executed a new command: 'system journal clear'.
Aug 20 19:17:41.286879 osdx OSDxCLI[712756]: User 'admin' executed a new command: 'system journal show | cat'.
Aug 20 19:17:41.478887 osdx OSDxCLI[712756]: User 'admin' executed a new command: 'system journal show | cat'.
Aug 20 19:17:42.682885 osdx OSDxCLI[712756]: User 'admin' executed a new command: 'system journal show | cat'.
Aug 20 19:17:43.894867 osdx OSDxCLI[712756]: User 'admin' executed a new command: 'system journal show | cat'.
Aug 20 19:17:45.118882 osdx OSDxCLI[712756]: User 'admin' executed a new command: 'system journal show | cat'.
Aug 20 19:17:46.358934 osdx OSDxCLI[712756]: User 'admin' executed a new command: 'system journal show | cat'.
Aug 20 19:17:47.602887 osdx OSDxCLI[712756]: User 'admin' executed a new command: 'system journal show | cat'.
Aug 20 19:17:48.854893 osdx OSDxCLI[712756]: User 'admin' executed a new command: 'system journal show | cat'.
Aug 20 19:17:50.118893 osdx OSDxCLI[712756]: User 'admin' executed a new command: 'system journal show | cat'.
Aug 20 19:17:51.394873 osdx OSDxCLI[712756]: User 'admin' executed a new command: 'system journal show | cat'.
Aug 20 19:17:51.616469 osdx wwan-module[716852]: [Core/cell0] Info: Signal '12' received to reconnect device.
Aug 20 19:17:51.616519 osdx wwan-module[716852]: [Device/cell0] Info: Stopping network connection...
Aug 20 19:17:51.634615 osdx wwan-module[717226]: Network cancelled... releasing resources
Aug 20 19:17:51.770625 osdx wwan-module[717226]: [/dev/cdc-wdm0] Network stopped
Aug 20 19:17:51.770625 osdx wwan-module[717226]: [/dev/cdc-wdm0] Client ID not released:
Aug 20 19:17:51.770625 osdx wwan-module[717226]:         Service: 'wds'
Aug 20 19:17:51.770625 osdx wwan-module[717226]:             CID: '21'
Aug 20 19:17:51.772475 osdx wwan-module[716852]: [Device/cell0] Info: Network connection was stopped!
Aug 20 19:17:51.774564 osdx wwan-module[716852]: [Network/cell0] Info: Stopping accessibility control...
Aug 20 19:17:51.774780 osdx wwan-module[716852]: [Network/cell0] Info: Accessibility control was stopped!
Aug 20 19:17:51.777787 osdx kernel: net cell0: link_state 0x1 -> 0x0
Aug 20 19:17:51.788181 osdx modulelauncher[717233]: stop DHCP client for cell0
Aug 20 19:17:51.789119 osdx dhclient[716940]: receive_packet failed on cell0: Network is down
Aug 20 19:17:51.791164 osdx wwan-module[716852]: [Device/cell0] Info: Checking registration state...
Aug 20 19:17:51.798510 osdx dhclient[717237]: Killed old client process
Aug 20 19:17:51.898637 osdx wwan-module[716852]: [Device/cell0] Info: Device registered and PS attached successfully
Aug 20 19:17:51.898659 osdx wwan-module[716852]: [Device/cell0] Info: Establishing network connection...
Aug 20 19:17:51.926035 osdx dhclient[717237]: DHCPRELEASE of 37.12.70.217 on cell0 to 37.12.70.218 port 67
Aug 20 19:17:51.926067 osdx dhclient[717237]: send_packet: Network is down
Aug 20 19:17:51.926079 osdx dhclient[717237]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.
Aug 20 19:17:52.168524 osdx wwan-module[716852]: [Device/cell0] Info: Network connection was successfully started: PDH=[452065616]
Aug 20 19:17:52.284786 osdx wwan-module[716852]: [Network/cell0] Info: Starting accessibility control...
Aug 20 19:17:52.285116 osdx wwan-module[716852]: [Network/cell0] Info: Accessibility control was started!
Aug 20 19:17:52.285610 osdx kernel: net cell0: link_state 0x0 -> 0x1
Aug 20 19:17:52.506491 osdx modulelauncher[717286]: start DHCP client for cell0