What is relationship between total_steps and num_steps of file pipeline.config?

I'm working on training a model by using Transfer Learning. The pre-trained model I use is "SSD MobileNet V2 FPNLite 320x320" from Model Zoo TF2. And I have some confusion about item train_config, in file pipeline.config.

If I change num_steps, model will train with num_steps. But when I change total_steps, the model still train with num_steps. Even if I setnum_steps > total_step, there is no error. And when I check all SSD model in Model Zoo TF2, I always see that total_steps the same as num_steps.

• Question: Do I need to set total_steps the same with num_steps? What is the relationship between it?

train_config {
  batch_size: 128
  data_augmentation_options {
    random_horizontal_flip {
    }
  }
  data_augmentation_options {
    random_crop_image {
      min_object_covered: 0.0
      min_aspect_ratio: 0.75
      max_aspect_ratio: 3.0
      min_area: 0.75
      max_area: 1.0
      overlap_thresh: 0.0
    }
  }
  sync_replicas: true
  optimizer {
    momentum_optimizer {
      learning_rate {
        cosine_decay_learning_rate {
          learning_rate_base: 0.07999999821186066
          total_steps: 50000
          warmup_learning_rate: 0.026666000485420227
          warmup_steps: 1000
        }
      }
      momentum_optimizer_value: 0.8999999761581421
    }
    use_moving_average: false
  }
  fine_tune_checkpoint: "PATH_TO_BE_CONFIGURED"
  num_steps: 50000
  startup_delay_steps: 0.0
  replicas_to_aggregate: 8
  max_number_of_boxes: 100
  unpad_groundtruth_tensors: false
  fine_tune_checkpoint_type: "classification"
  fine_tune_checkpoint_version: V2
}