Abstract: This application discloses an advertisement information processing method. The method includes a first node receives, in a first IGP process, first advertisement information that is sent by a second node and that includes a destination address of the second node and a first identifier indicating, in the first IGP process, a first flexible algorithm. The first node determines whether the first identifier indicates, in a second IGP process, a flexible algorithm the same as the first flexible algorithm. When the first identifier does not indicate, in the second IGP process, the flexible algorithm the same as the first flexible algorithm, the first node advertises, in the second IGP process, second advertisement information that includes the destination address and a second identifier indicating, in the second IGP process, a second flexible algorithm, or skips advertising third advertisement information that includes the destination address.