Scrapy's distributed crawling can be implemented through the scrapy-redis component. scrapy-redis is a Scrapy component based on Redis that replaces Scrapy's scheduler and deduplication functionality with Redis implementations, allowing multiple spider instances to share task queues and deduplication sets. In distributed crawling, one spider instance is responsible for retrieving requests from Redis and processing them, while other spider instances can also retrieve requests from Redis simultaneously, achieving load balancing. scrapy-redis provides components such as RedisScheduler, RedisDupeFilter, and RedisPipeline for scheduling, deduplication, and data storage respectively. When using scrapy-redis, you need to configure Redis connection information in settings.py and set the scheduler and deduplication classes to the classes provided by scrapy-redis. The advantages of distributed crawling include increased crawling speed, enhanced fault tolerance, and the ability to dynamically add or remove spider instances. It's important to note that distributed crawling needs to consider data consistency and task allocation issues.