Route advertisement method, device, and system

A first network device, comprising:

• a memory configured to store instructions;
• and
• a processor coupled to the memory and configured to execute the instructions to cause the first network device to be configured to:
• receive Border Gateway Protocol (BGP) service routing information from a second network device in a network, wherein the BGP service routing information comprises a destination address and a next-hop address to the destination address, wherein a cross-domain end-to-end tunnel carries a service in the network, wherein the cross-domain end-to-end tunnel crosses at least two Interior Gateway Protocol (IGP) network domains, and wherein the at least two IGP network domains comprise the first network device, the second network device, and a third network device;
• skip performing route recursion on the next-hop address;
• and
• advertise the BGP service routing information to the third network device.

A control and management device, comprising:

• a memory configured to store instructions;
• and
• a processor coupled to the memory and configured to execute the instructions to cause the control and management device to be configured to:
• generate a first message comprising first policy information, wherein the first policy information comprises an indication to a first network device in a network to not perform route recursion, wherein a cross-domain end-to-end tunnel carries a service in the network, wherein the cross-domain end-to-end tunnel crosses at least two Interior Gateway Protocol (IGP) network domains, and wherein the at least two IGP network domains comprise the first network device, a second network device, and a third network device;
• and
• advertise the first message to the first network device.