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+AbnaWwJCwngVKmssdZrIY4bxQq/2eenA=
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 23:27:29.878637 osdx systemd-journald[98664]: Runtime Journal (/run/log/journal/744d91d0e74f4d8d8c05bc34a7d20cdd) is 1.0M, max 8.5M, 7.4M free.
Feb 19 23:27:29.880826 osdx systemd-journald[98664]: Received client request to rotate journal, rotating.
Feb 19 23:27:29.881022 osdx systemd-journald[98664]: Vacuuming done, freed 0B of archived journals from /run/log/journal/744d91d0e74f4d8d8c05bc34a7d20cdd.
Feb 19 23:27:29.970971 osdx OSDxCLI[500934]: User 'admin' executed a new command: 'system journal clear'.
Feb 19 23:27:50.145044 osdx OSDxCLI[500934]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 23:27:50.329036 osdx OSDxCLI[500934]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 23:27:51.529036 osdx OSDxCLI[500934]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 23:27:52.789037 osdx OSDxCLI[500934]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 23:27:54.021101 osdx OSDxCLI[500934]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 23:27:55.241032 osdx OSDxCLI[500934]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 23:27:56.485029 osdx OSDxCLI[500934]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 23:27:57.837028 osdx OSDxCLI[500934]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 23:27:59.085066 osdx OSDxCLI[500934]: User 'admin' executed a new command: 'system journal show | cat'.
Feb 19 23:27:59.753910 osdx wwan-module[501870]: [Core/cell0] Info: Signal '12' received to reconnect device.
Feb 19 23:27:59.753958 osdx wwan-module[501870]: [Device/cell0] Info: Stopping network connection...
Feb 19 23:27:59.772040 osdx wwan-module[502178]: Network cancelled... releasing resources
Feb 19 23:27:59.872465 osdx wwan-module[502178]: [/dev/cdc-wdm0] Network stopped
Feb 19 23:27:59.872465 osdx wwan-module[502178]: [/dev/cdc-wdm0] Client ID not released:
Feb 19 23:27:59.872465 osdx wwan-module[502178]:         Service: 'wds'
Feb 19 23:27:59.872465 osdx wwan-module[502178]:             CID: '21'
Feb 19 23:27:59.874264 osdx wwan-module[501870]: [Device/cell0] Info: Network connection was stopped!
Feb 19 23:27:59.876355 osdx wwan-module[501870]: [Network/cell0] Info: Stopping accessibility control...
Feb 19 23:27:59.876876 osdx wwan-module[501870]: [Device/cell0] Info: Accessibility control was stopped!
Feb 19 23:27:59.879756 osdx kernel: net cell0: link_state 0x1 -> 0x0
Feb 19 23:27:59.889941 osdx modulelauncher[502185]: stop DHCP client for cell0
Feb 19 23:27:59.892387 osdx dhclient[501931]: receive_packet failed on cell0: Network is down
Feb 19 23:27:59.894365 osdx wwan-module[501870]: [Device/cell0] Info: Establishing network connection...
Feb 19 23:27:59.901738 osdx dhclient[502190]: Killed old client process
Feb 19 23:28:00.024284 osdx dhclient[502190]: DHCPRELEASE of 37.12.47.116 on cell0 to 37.12.47.117 port 67
Feb 19 23:28:00.024316 osdx dhclient[502190]: send_packet: Network is down
Feb 19 23:28:00.024328 osdx dhclient[502190]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.
Feb 19 23:28:00.198237 osdx wwan-module[501870]: [Device/cell0] Info: Network connection was successfully started: PDH=[2175564688]
Feb 19 23:28:00.202348 osdx wwan-module[501870]: [Network/cell0] Info: Starting accessibility control...
Feb 19 23:28:00.202689 osdx wwan-module[501870]: [Network/cell0] Info: Accessibility control was started!