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 U2FsdGVkX18ox+MjgJJ6hrgXFnYA9x4h6iQ6cHzFQZY=
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

Nov 12 12:58:12.878304 osdx systemd-journald[1889]: Runtime Journal (/run/log/journal/66618607d34347599ce4ba4fda545c32) is 4.8M, max 38.4M, 33.6M free.
Nov 12 12:58:12.883249 osdx systemd-journald[1889]: Received client request to rotate journal, rotating.
Nov 12 12:58:12.883448 osdx systemd-journald[1889]: Vacuuming done, freed 0B of archived journals from /run/log/journal/66618607d34347599ce4ba4fda545c32.
Nov 12 12:58:12.973892 osdx OSDxCLI[95501]: User 'admin' executed a new command: 'system journal clear'.
Nov 12 12:58:33.155930 osdx OSDxCLI[95501]: User 'admin' executed a new command: 'system journal show | cat'.
Nov 12 12:58:33.347929 osdx OSDxCLI[95501]: User 'admin' executed a new command: 'system journal show | cat'.
Nov 12 12:58:34.547959 osdx OSDxCLI[95501]: User 'admin' executed a new command: 'system journal show | cat'.
Nov 12 12:58:35.747927 osdx OSDxCLI[95501]: User 'admin' executed a new command: 'system journal show | cat'.
Nov 12 12:58:36.991934 osdx OSDxCLI[95501]: User 'admin' executed a new command: 'system journal show | cat'.
Nov 12 12:58:38.223934 osdx OSDxCLI[95501]: User 'admin' executed a new command: 'system journal show | cat'.
Nov 12 12:58:39.455930 osdx OSDxCLI[95501]: User 'admin' executed a new command: 'system journal show | cat'.
Nov 12 12:58:40.695948 osdx OSDxCLI[95501]: User 'admin' executed a new command: 'system journal show | cat'.
Nov 12 12:58:42.007941 osdx OSDxCLI[95501]: User 'admin' executed a new command: 'system journal show | cat'.
Nov 12 12:58:42.940608 osdx wwan-module[99048]: [Core/cell0] Info: Signal '12' received to reconnect device.
Nov 12 12:58:42.940659 osdx wwan-module[99048]: [Device/cell0] Info: Stopping network connection...
Nov 12 12:58:42.958678 osdx wwan-module[99654]: Network cancelled... releasing resources
Nov 12 12:58:43.095543 osdx wwan-module[99654]: [/dev/cdc-wdm0] Network stopped
Nov 12 12:58:43.095543 osdx wwan-module[99654]: [/dev/cdc-wdm0] Client ID not released:
Nov 12 12:58:43.095543 osdx wwan-module[99654]:         Service: 'wds'
Nov 12 12:58:43.095543 osdx wwan-module[99654]:             CID: '21'
Nov 12 12:58:43.097319 osdx wwan-module[99048]: [Device/cell0] Info: Network connection was stopped!
Nov 12 12:58:43.099506 osdx wwan-module[99048]: [Network/cell0] Info: Stopping accessibility control...
Nov 12 12:58:43.099758 osdx wwan-module[99048]: [Network/cell0] Info: Accessibility control was stopped!
Nov 12 12:58:43.103957 osdx kernel: net cell0: link_state 0x1 -> 0x0
Nov 12 12:58:43.114527 osdx dhclient[99357]: receive_packet failed on cell0: Network is down
Nov 12 12:58:43.115484 osdx modulelauncher[99662]: stop DHCP client for cell0
Nov 12 12:58:43.116628 osdx wwan-module[99048]: [Device/cell0] Info: Checking registration state...
Nov 12 12:58:43.126133 osdx dhclient[99667]: Killed old client process
Nov 12 12:58:43.223914 osdx wwan-module[99048]: [Device/cell0] Info: Device registered and PS attached successfully
Nov 12 12:58:43.223940 osdx wwan-module[99048]: [Device/cell0] Info: Establishing network connection...
Nov 12 12:58:43.271077 osdx dhclient[99667]: DHCPRELEASE of 88.31.93.95 on cell0 to 88.31.93.96 port 67
Nov 12 12:58:43.271105 osdx dhclient[99667]: send_packet: Network is down
Nov 12 12:58:43.271117 osdx dhclient[99667]: dhclient.c:3146: Failed to send 300 byte long packet over cell0 interface.
Nov 12 12:58:43.436163 osdx OSDxCLI[95501]: User 'admin' executed a new command: 'system journal show | cat'.
Nov 12 12:58:43.549028 osdx wwan-module[99048]: [Device/cell0] Info: Network connection was successfully started: PDH=[2175556032]
Nov 12 12:58:43.674640 osdx kernel: net cell0: link_state 0x0 -> 0x1
Nov 12 12:58:43.675933 osdx wwan-module[99048]: [Network/cell0] Info: Starting accessibility control...
Nov 12 12:58:43.676238 osdx wwan-module[99048]: [Network/cell0] Info: Accessibility control was started!
Nov 12 12:58:43.903975 osdx modulelauncher[99720]: start DHCP client for cell0
Nov 12 12:58:44.106667 osdx kernel: IPv6: ADDRCONF(NETDEV_CHANGE): cell0: link becomes ready
Nov 12 12:58:44.427067 osdx dhclient[99729]: DHCPDISCOVER on cell0 to 255.255.255.255 port 67 interval 3
Nov 12 12:58:44.432420 osdx dhclient[99729]: DHCPOFFER of 88.31.84.29 from 88.31.84.30
Nov 12 12:58:44.432522 osdx dhclient[99729]: DHCPREQUEST for 88.31.84.29 on cell0 to 255.255.255.255 port 67
Nov 12 12:58:44.434176 osdx dhclient[99729]: DHCPACK of 88.31.84.29 from 88.31.84.30