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+E46/F8CvLif2kzt0Y9w6NU8unLjVutbc=
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

Sep 05 10:35:54.112400 osdx systemd-journald[1704]: Runtime Journal (/run/log/journal/6686752e0f604a69929013fabf37f11d) is 4.8M, max 38.4M, 33.6M free.
Sep 05 10:35:54.117282 osdx systemd-journald[1704]: Received client request to rotate journal, rotating.
Sep 05 10:35:54.117490 osdx systemd-journald[1704]: Vacuuming done, freed 0B of archived journals from /run/log/journal/6686752e0f604a69929013fabf37f11d.
Sep 05 10:35:54.208390 osdx OSDxCLI[70214]: User 'admin' executed a new command: 'system journal clear'.
Sep 05 10:36:14.414464 osdx OSDxCLI[70214]: User 'admin' executed a new command: 'system journal show | cat'.
Sep 05 10:36:14.598468 osdx OSDxCLI[70214]: User 'admin' executed a new command: 'system journal show | cat'.
Sep 05 10:36:15.798469 osdx OSDxCLI[70214]: User 'admin' executed a new command: 'system journal show | cat'.
Sep 05 10:36:16.998597 osdx OSDxCLI[70214]: User 'admin' executed a new command: 'system journal show | cat'.
Sep 05 10:36:18.230482 osdx OSDxCLI[70214]: User 'admin' executed a new command: 'system journal show | cat'.
Sep 05 10:36:19.454477 osdx OSDxCLI[70214]: User 'admin' executed a new command: 'system journal show | cat'.
Sep 05 10:36:20.682490 osdx OSDxCLI[70214]: User 'admin' executed a new command: 'system journal show | cat'.
Sep 05 10:36:22.010467 osdx OSDxCLI[70214]: User 'admin' executed a new command: 'system journal show | cat'.
Sep 05 10:36:23.258469 osdx OSDxCLI[70214]: User 'admin' executed a new command: 'system journal show | cat'.
Sep 05 10:36:24.514478 osdx OSDxCLI[70214]: User 'admin' executed a new command: 'system journal show | cat'.
Sep 05 10:36:24.551236 osdx wwan-module[71514]: [Core/cell0] Info: Signal '12' received to reconnect device.
Sep 05 10:36:24.551285 osdx wwan-module[71514]: [Device/cell0] Info: Stopping network connection...
Sep 05 10:36:24.569227 osdx wwan-module[71929]: Network cancelled... releasing resources
Sep 05 10:36:24.706415 osdx wwan-module[71929]: [/dev/cdc-wdm0] Network stopped
Sep 05 10:36:24.706415 osdx wwan-module[71929]: [/dev/cdc-wdm0] Client ID not released:
Sep 05 10:36:24.706415 osdx wwan-module[71929]:         Service: 'wds'
Sep 05 10:36:24.706415 osdx wwan-module[71929]:             CID: '21'
Sep 05 10:36:24.708270 osdx wwan-module[71514]: [Device/cell0] Info: Network connection was stopped!
Sep 05 10:36:24.710357 osdx wwan-module[71514]: [Network/cell0] Info: Stopping accessibility control...
Sep 05 10:36:24.710547 osdx wwan-module[71514]: [Network/cell0] Info: Accessibility control was stopped!
Sep 05 10:36:24.713186 osdx kernel: net cell0: link_state 0x1 -> 0x0
Sep 05 10:36:24.723583 osdx modulelauncher[71936]: stop DHCP client for cell0
Sep 05 10:36:24.725987 osdx dhclient[71626]: receive_packet failed on cell0: Network is down
Sep 05 10:36:24.727975 osdx wwan-module[71514]: [Device/cell0] Info: Checking registration state...
Sep 05 10:36:24.733912 osdx dhclient[71940]: Killed old client process
Sep 05 10:36:24.834206 osdx wwan-module[71514]: [Device/cell0] Info: Device registered and PS attached successfully
Sep 05 10:36:24.834235 osdx wwan-module[71514]: [Device/cell0] Info: Establishing network connection...
Sep 05 10:36:24.877629 osdx dhclient[71940]: DHCPRELEASE of 5.205.183.16 on cell0 to 5.205.183.17 port 67
Sep 05 10:36:24.877657 osdx dhclient[71940]: send_packet: Network is down
Sep 05 10:36:24.877670 osdx dhclient[71940]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.
Sep 05 10:36:25.199020 osdx wwan-module[71514]: [Device/cell0] Info: Network connection was successfully started: PDH=[1945238944]
Sep 05 10:36:25.317192 osdx kernel: net cell0: link_state 0x0 -> 0x1
Sep 05 10:36:25.318134 osdx wwan-module[71514]: [Network/cell0] Info: Starting accessibility control...
Sep 05 10:36:25.318570 osdx wwan-module[71514]: [Network/cell0] Info: Accessibility control was started!
Sep 05 10:36:25.478687 osdx modulelauncher[71989]: start DHCP client for cell0