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+1q8jetGEgybb/YTEn91OGOp78RtoDkGU=
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

Jan 10 14:22:17.698037 osdx systemd-journald[1668]: Runtime Journal (/run/log/journal/b71221f9821e4f109a404f7e423b2684) is 1.0M, max 8.5M, 7.4M free.
Jan 10 14:22:17.700192 osdx systemd-journald[1668]: Received client request to rotate journal, rotating.
Jan 10 14:22:17.700385 osdx systemd-journald[1668]: Vacuuming done, freed 0B of archived journals from /run/log/journal/b71221f9821e4f109a404f7e423b2684.
Jan 10 14:22:17.789630 osdx OSDxCLI[59820]: User 'admin' executed a new command: 'system journal clear'.
Jan 10 14:22:37.987578 osdx OSDxCLI[59820]: User 'admin' executed a new command: 'system journal show | cat'.
Jan 10 14:22:38.171610 osdx OSDxCLI[59820]: User 'admin' executed a new command: 'system journal show | cat'.
Jan 10 14:22:39.363597 osdx OSDxCLI[59820]: User 'admin' executed a new command: 'system journal show | cat'.
Jan 10 14:22:40.563594 osdx OSDxCLI[59820]: User 'admin' executed a new command: 'system journal show | cat'.
Jan 10 14:22:41.771589 osdx OSDxCLI[59820]: User 'admin' executed a new command: 'system journal show | cat'.
Jan 10 14:22:42.999589 osdx OSDxCLI[59820]: User 'admin' executed a new command: 'system journal show | cat'.
Jan 10 14:22:44.231598 osdx OSDxCLI[59820]: User 'admin' executed a new command: 'system journal show | cat'.
Jan 10 14:22:45.499592 osdx OSDxCLI[59820]: User 'admin' executed a new command: 'system journal show | cat'.
Jan 10 14:22:46.751603 osdx OSDxCLI[59820]: User 'admin' executed a new command: 'system journal show | cat'.
Jan 10 14:22:47.353435 osdx wwan-module[63085]: [Core/cell0] Info: Signal '12' received to reconnect device.
Jan 10 14:22:47.353481 osdx wwan-module[63085]: [Device/cell0] Info: Stopping network connection...
Jan 10 14:22:47.371581 osdx wwan-module[63634]: Network cancelled... releasing resources
Jan 10 14:22:47.470603 osdx wwan-module[63634]: [/dev/cdc-wdm0] Network stopped
Jan 10 14:22:47.470603 osdx wwan-module[63634]: [/dev/cdc-wdm0] Client ID not released:
Jan 10 14:22:47.470603 osdx wwan-module[63634]:         Service: 'wds'
Jan 10 14:22:47.470603 osdx wwan-module[63634]:             CID: '21'
Jan 10 14:22:47.472397 osdx wwan-module[63085]: [Device/cell0] Info: Network connection was stopped!
Jan 10 14:22:47.474503 osdx wwan-module[63085]: [Network/cell0] Info: Stopping accessibility control...
Jan 10 14:22:47.474733 osdx wwan-module[63085]: [Device/cell0] Info: Accessibility control was stopped!
Jan 10 14:22:47.478408 osdx kernel: net cell0: link_state 0x1 -> 0x0
Jan 10 14:22:47.487796 osdx modulelauncher[63641]: stop DHCP client for cell0
Jan 10 14:22:47.488411 osdx dhclient[63152]: receive_packet failed on cell0: Network is down
Jan 10 14:22:47.490426 osdx wwan-module[63085]: [Device/cell0] Info: Establishing network connection...
Jan 10 14:22:47.498729 osdx dhclient[63646]: Killed old client process
Jan 10 14:22:47.626869 osdx dhclient[63646]: DHCPRELEASE of 88.31.6.135 on cell0 to 88.31.6.136 port 67
Jan 10 14:22:47.626904 osdx dhclient[63646]: send_packet: Network is down
Jan 10 14:22:47.626916 osdx dhclient[63646]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.
Jan 10 14:22:47.765259 osdx wwan-module[63085]: [Device/cell0] Info: Network connection was successfully started: PDH=[4138882384]
Jan 10 14:22:47.770497 osdx kernel: net cell0: link_state 0x0 -> 0x1
Jan 10 14:22:47.770993 osdx wwan-module[63085]: [Network/cell0] Info: Starting accessibility control...
Jan 10 14:22:47.771285 osdx wwan-module[63085]: [Network/cell0] Info: Accessibility control was started!