How to use the command l2ping (with examples)

The l2ping command is a Linux command that allows you to send an L2CAP (Logical Link Control and Adaptation Protocol) echo request to a Bluetooth device and receive an answer. It is used to test the connectivity and latency between your device and a Bluetooth device.

Use case 1: Ping a Bluetooth device

Code:

sudo l2ping mac_address

Motivation: You might want to ping a Bluetooth device to check if it is within range and establish a connection.

Explanation:

• sudo: The sudo command is used to execute the following command with administrative privileges.
• l2ping: The l2ping command is used to send an L2CAP echo request.
• mac_address: Replace this with the Bluetooth device’s MAC address.

Example output:

Ping: 00:11:22:33:44:55 from 00:AA:BB:CC:DD:EE (data size 44) ...
44 bytes from 00:11:22:33:44:55 id 0 time 20.50ms

Use case 2: Reverse ping a Bluetooth device

Code:

sudo l2ping -r mac_address

Motivation: A reverse ping is useful in scenarios where the remote Bluetooth device has limited connectivity capabilities. By using a reverse ping, the remote device can respond to your request even if it was unable to initiate the connection.

Explanation:

• -r: The -r option is used for reverse pinging a Bluetooth device.
• mac_address: Replace this with the Bluetooth device’s MAC address.

Example output:

Reply from mac_address: Reverse Ping is successful.

Use case 3: Ping a Bluetooth device from a specified interface

Code:

sudo l2ping -i hci0 mac_address

Motivation: If you have multiple Bluetooth interfaces on your device, you can use this command to specify the interface to be used for the ping.

Explanation:

• -i hci0: The -i option is used to specify the Bluetooth interface to be used for the ping. Replace hci0 with the desired interface name.
• mac_address: Replace this with the Bluetooth device’s MAC address.

Example output:

Ping: 00:11:22:33:44:55 from 00:AA:BB:CC:DD:EE hci0 (data size 44) ...
44 bytes from 00:11:22:33:44:55 id 0 time 20.50ms

Use case 4: Ping a Bluetooth device with a specified sized data package

Code:

sudo l2ping -s byte_count mac_address

Motivation: By default, the ping uses a data package size of 44 bytes. You can use this command to specify a different data package size, which allows you to test the performance of the Bluetooth connection with different payload sizes.

Explanation:

• -s byte_count: The -s option is used to specify the data package size in bytes.
• byte_count: Replace this with the desired data package size (in bytes).
• mac_address: Replace this with the Bluetooth device’s MAC address.

Example output:

Ping: 00:11:22:33:44:55 from 00:AA:BB:CC:DD:EE (data size 100) ...
100 bytes from 00:11:22:33:44:55 id 0 time 25.70ms

Use case 5: Ping flood a Bluetooth device

Code:

sudo l2ping -f mac_address

Motivation: This command is used to flood a Bluetooth device with repeated ping requests, which can help test the stability and performance of the connection under heavy load.

Explanation:

• -f: The -f option is used to enable ping flooding.
• mac_address: Replace this with the Bluetooth device’s MAC address.

Example output:

Flood ping: 00:11:22:33:44:55 from 00:AA:BB:CC:DD:EE (data size 44) ...
.
...[snipped output]...
.

Use case 6: Ping a Bluetooth device a specified amount of times

Code:

sudo l2ping -c amount mac_address

Motivation: In some scenarios, you may want to ping a Bluetooth device a specific number of times to measure the average response time or check for packet loss.

Explanation:

• -c amount: The -c option is used to specify the number of pings to send.
• amount: Replace this with the desired number of pings.
• mac_address: Replace this with the Bluetooth device’s MAC address.

Example output:

Ping: 00:11:22:33:44:55 from 00:AA:BB:CC:DD:EE (data size 44) ...
44 bytes from 00:11:22:33:44:55 id 0 time 20.50ms
...
97 packets transmitted, 97 received, 0% packet loss

Use case 7: Ping a Bluetooth device with a specified delay between requests

Code:

sudo l2ping -d seconds mac_address

Motivation: This command allows you to add a specific delay between each ping request, which can simulate a more realistic usage scenario or test the performance of the connection over a longer period of time.

Explanation:

• -d seconds: The -d option is used to specify the delay between each ping request in seconds.
• seconds: Replace this with the desired delay in seconds.
• mac_address: Replace this with the Bluetooth device’s MAC address.

Example output:

Ping: 00:11:22:33:44:55 from 00:AA:BB:CC:DD:EE (data size 44) ...
44 bytes from 00:11:22:33:44:55 id 0 time 20.50ms
...

Conclusion:

The l2ping command is a versatile tool for testing Bluetooth device connectivity and performance. With various options, you can customize the ping behavior to suit your specific requirements. Whether you need to simply verify if a Bluetooth device is reachable or perform more advanced performance tests, the l2ping command can help you accomplish these tasks efficiently.