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 U2FsdGVkX18Wn5HxLAxnE0yC4aiymp2drRgM+gwGCrg=
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 25 16:47:53.024455 osdx systemd-journald[529987]: Runtime Journal (/run/log/journal/1976ff34d2ab4f28bcb52a47607ffb21) is 1.0M, max 8.5M, 7.5M free.
Jun 25 16:47:53.026830 osdx systemd-journald[529987]: Received client request to rotate journal, rotating.
Jun 25 16:47:53.027031 osdx systemd-journald[529987]: Vacuuming done, freed 0B of archived journals from /run/log/journal/1976ff34d2ab4f28bcb52a47607ffb21.
Jun 25 16:47:53.049019 osdx sudo[670431]: pam_limits(sudo:session): invalid line '@200:215        hard        maxlogins        ' - skipped
Jun 25 16:47:53.115908 osdx OSDxCLI[666882]: User 'admin' executed a new command: 'system journal clear'.
Jun 25 16:48:01.661699 osdx CRON[670448]: pam_limits(cron:session): invalid line '@200:215        hard        maxlogins        ' - skipped
Jun 25 16:48:13.313916 osdx OSDxCLI[666882]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 25 16:48:13.537910 osdx OSDxCLI[666882]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 25 16:48:14.753934 osdx OSDxCLI[666882]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 25 16:48:15.977938 osdx OSDxCLI[666882]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 25 16:48:17.217907 osdx OSDxCLI[666882]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 25 16:48:18.505920 osdx OSDxCLI[666882]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 25 16:48:19.777941 osdx OSDxCLI[666882]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 25 16:48:21.041932 osdx OSDxCLI[666882]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 25 16:48:22.317927 osdx OSDxCLI[666882]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 25 16:48:23.538563 osdx wwan-module[670164]: [Core/cell0] Info: Signal '12' received to reconnect device.
Jun 25 16:48:23.538611 osdx wwan-module[670164]: [Device/cell0] Info: Stopping network connection...
Jun 25 16:48:23.556791 osdx wwan-module[670530]: Network cancelled... releasing resources
Jun 25 16:48:23.601896 osdx OSDxCLI[666882]: User 'admin' executed a new command: 'system journal show | cat'.
Jun 25 16:48:23.693507 osdx wwan-module[670530]: [/dev/cdc-wdm0] Network stopped
Jun 25 16:48:23.693507 osdx wwan-module[670530]: [/dev/cdc-wdm0] Client ID not released:
Jun 25 16:48:23.693507 osdx wwan-module[670530]:         Service: 'wds'
Jun 25 16:48:23.693507 osdx wwan-module[670530]:             CID: '21'
Jun 25 16:48:23.695366 osdx wwan-module[670164]: [Device/cell0] Info: Network connection was stopped!
Jun 25 16:48:23.697489 osdx wwan-module[670164]: [Network/cell0] Info: Stopping accessibility control...
Jun 25 16:48:23.697996 osdx wwan-module[670164]: [Network/cell0] Info: Accessibility control was stopped!
Jun 25 16:48:23.700637 osdx kernel: net cell0: link_state 0x1 -> 0x0
Jun 25 16:48:23.711296 osdx modulelauncher[670537]: stop DHCP client for cell0
Jun 25 16:48:23.713056 osdx dhclient[670252]: receive_packet failed on cell0: Network is down
Jun 25 16:48:23.714910 osdx wwan-module[670164]: [Device/cell0] Info: Checking registration state...
Jun 25 16:48:23.721333 osdx dhclient[670541]: Killed old client process
Jun 25 16:48:23.821763 osdx wwan-module[670164]: [Device/cell0] Info: Device registered and PS attached successfully
Jun 25 16:48:23.821786 osdx wwan-module[670164]: [Device/cell0] Info: Establishing network connection...
Jun 25 16:48:23.849102 osdx dhclient[670541]: DHCPRELEASE of 88.31.51.152 on cell0 to 88.31.51.153 port 67
Jun 25 16:48:23.849131 osdx dhclient[670541]: send_packet: Network is down
Jun 25 16:48:23.849142 osdx dhclient[670541]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.
Jun 25 16:48:24.178542 osdx wwan-module[670164]: [Device/cell0] Info: Network connection was successfully started: PDH=[2175566368]
Jun 25 16:48:24.304713 osdx kernel: net cell0: link_state 0x0 -> 0x1
Jun 25 16:48:24.306706 osdx wwan-module[670164]: [Network/cell0] Info: Starting accessibility control...
Jun 25 16:48:24.307152 osdx wwan-module[670164]: [Network/cell0] Info: Accessibility control was started!
Jun 25 16:48:24.428282 osdx modulelauncher[670590]: start DHCP client for cell0
Jun 25 16:48:24.716664 osdx kernel: IPv6: ADDRCONF(NETDEV_CHANGE): cell0: link becomes ready