A routing information processing method and apparatus. The method includes a first network device determines a first segment identifier corresponding to a second network device and a first locator. The first network device determines a second segment identifier corresponding to a third network device and a second locator. The first network device sends routing information that includes the first segment identifier and the second segment identifier. A fourth network device advertises mirror routing information specific to the first network device, where the mirror routing information includes the second segment identifier or the second locator.