9 PCAP File - Advanced Topics

9.1 Introduction

The RoboSense LiDAR may work

in unicast/multicast/broadcast mode,
with VLAN layer
with user layers.
Also rslidar_sdk supports multi-LiDARs.

This document illustrates how to configure rslidar_sdk in each case.

Before reading this document, please be sure that you have read:

9.2 General Case

Generally, below code is for decoding a PCAP file in these cases.

Broadcast/multicast/unicast mode
There are multiple LiDars in a file.

common:
  msg_source: 3                                       
  send_point_cloud_ros: true                            

lidar:
  - driver:
      lidar_type: RS32           
      pcap_path: /home/robosense/lidar.pcap
      msop_port: 6699
      difop_port: 7788
    ros:
      ros_frame_id: rslidar           
      ros_send_point_cloud_topic: /rslidar_points     

The only exception is “Multiple Lidars with same ports but different IPs”, which is not supported now.

9.3 VLAN

In some user cases, The LiDar may work on VLAN. Its packets have a VLAN layer.

rs_driver decodes PCAP file and gets all parts of MSOP packets, including the VLAN layer.

To strip the VLAN layer, just set use_vlan: true.

lidar:
  - driver:
      lidar_type: RS32           
      pcap_path: /home/robosense/lidar.pcap
      msop_port: 6699             
      difop_port: 7788
      use_vlan: true            

9.4 User Layer, Tail Layer

In some user cases, User may add extra layers before or/and after the MSOP/DIFOP packet.

USER_LAYER is before the packet and TAIL_LAYER is after it.

These extra layers are parts of UDP data. The driver can strip them.

To strip them, just give their lengths in bytes.

In the following example, USER_LAYER is 8 bytes, and TAIL_LAYER is 4 bytes.

lidar:
  - driver:
      lidar_type: RS32           
      pcap_path: /home/robosense/lidar.pcap
      msop_port: 6699             
      difop_port: 7788
      user_layer_bytes: 8
      tail_layer_bytes: 4      