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/E3kH4ewyMnxbxhiMXeXDENmCtV2fEqeQ=
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

May 26 12:40:02.965132 osdx systemd-journald[171198]: Runtime Journal (/run/log/journal/060bb715f8eb4c1eae5590345746a707) is 1.0M, max 8.5M, 7.4M free.
May 26 12:40:02.967529 osdx systemd-journald[171198]: Received client request to rotate journal, rotating.
May 26 12:40:02.967748 osdx systemd-journald[171198]: Vacuuming done, freed 0B of archived journals from /run/log/journal/060bb715f8eb4c1eae5590345746a707.
May 26 12:40:03.054813 osdx OSDxCLI[180412]: User 'admin' executed a new command: 'system journal clear'.
May 26 12:40:23.224836 osdx OSDxCLI[180412]: User 'admin' executed a new command: 'system journal show | cat'.
May 26 12:40:23.408795 osdx OSDxCLI[180412]: User 'admin' executed a new command: 'system journal show | cat'.
May 26 12:40:24.600832 osdx OSDxCLI[180412]: User 'admin' executed a new command: 'system journal show | cat'.
May 26 12:40:25.812792 osdx OSDxCLI[180412]: User 'admin' executed a new command: 'system journal show | cat'.
May 26 12:40:27.048804 osdx OSDxCLI[180412]: User 'admin' executed a new command: 'system journal show | cat'.
May 26 12:40:28.280815 osdx OSDxCLI[180412]: User 'admin' executed a new command: 'system journal show | cat'.
May 26 12:40:29.516796 osdx OSDxCLI[180412]: User 'admin' executed a new command: 'system journal show | cat'.
May 26 12:40:30.772809 osdx OSDxCLI[180412]: User 'admin' executed a new command: 'system journal show | cat'.
May 26 12:40:32.028801 osdx OSDxCLI[180412]: User 'admin' executed a new command: 'system journal show | cat'.
May 26 12:40:32.443414 osdx wwan-module[181579]: [Core/cell0] Info: Signal '12' received to reconnect device.
May 26 12:40:32.443519 osdx wwan-module[181579]: [Device/cell0] Info: Stopping network connection...
May 26 12:40:32.461562 osdx wwan-module[181888]: Network cancelled... releasing resources
May 26 12:40:32.496466 osdx wwan-module[181888]: [/dev/cdc-wdm0] Network stopped
May 26 12:40:32.496466 osdx wwan-module[181888]: [/dev/cdc-wdm0] Client ID not released:
May 26 12:40:32.496466 osdx wwan-module[181888]:         Service: 'wds'
May 26 12:40:32.496466 osdx wwan-module[181888]:             CID: '21'
May 26 12:40:32.498291 osdx wwan-module[181579]: [Device/cell0] Info: Network connection was stopped!
May 26 12:40:32.500377 osdx wwan-module[181579]: [Network/cell0] Info: Stopping accessibility control...
May 26 12:40:32.500897 osdx wwan-module[181579]: [Device/cell0] Info: Accessibility control was stopped!
May 26 12:40:32.503535 osdx kernel: net cell0: link_state 0x1 -> 0x0
May 26 12:40:32.514343 osdx modulelauncher[181895]: stop DHCP client for cell0
May 26 12:40:32.515302 osdx dhclient[181646]: receive_packet failed on cell0: Network is down
May 26 12:40:32.517281 osdx wwan-module[181579]: [Device/cell0] Info: Establishing network connection...
May 26 12:40:32.525517 osdx dhclient[181900]: Killed old client process
May 26 12:40:32.629006 osdx wwan-module[181579]: [Device/cell0] Info: Network connection was successfully started: PDH=[2175609376]
May 26 12:40:32.631515 osdx kernel: net cell0: link_state 0x0 -> 0x1
May 26 12:40:32.632702 osdx wwan-module[181579]: [Network/cell0] Info: Starting accessibility control...
May 26 12:40:32.633007 osdx wwan-module[181579]: [Network/cell0] Info: Accessibility control was started!
May 26 12:40:32.647889 osdx dhclient[181900]: DHCPRELEASE of 5.205.191.179 on cell0 to 5.205.191.180 port 67
May 26 12:40:32.647917 osdx dhclient[181900]: send_packet: Network is down
May 26 12:40:32.647930 osdx dhclient[181900]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.
May 26 12:40:33.461259 osdx modulelauncher[181924]: start DHCP client for cell0
May 26 12:40:33.507559 osdx kernel: IPv6: ADDRCONF(NETDEV_CHANGE): cell0: link becomes ready