A method comprising: determining, by an Intermediate System to Intermediate System, IS-IS, adjacency state machine executed by processing circuitry of a first network device (16, 40, 302) of a plurality of network devices (16, 40, 302) in a network comprising a dual-stack IS-IS network and operating in accordance with a link state routing protocol, that a first logical link (20A, 20B) according to a first networking protocol (52, 54) is active, wherein the first logical link is established on a first physical link (22, 304) between the first network device and a second network device (16, 40, 302) of the plurality of network devices; determining, by the adjacency state machine, that a second logical link (20A, 20B) according to a second networking protocol is active, wherein the second logical link is established on the first physical link between the first network device and the second network device, and wherein the first networking protocol and second networking protocol are different; in response to determining that both the first logical link and the second logical link are active, determining, by the adjacency state machine, that the second network device is adjacent to the first network device; and in response to determining that the second network device is adjacent to the first network device: outputting a first link state routing advertisement advertising the adjacency between the second network device and the first network device, the adjacency being via the first logical link; and outputting a second link state routing advertisement advertising the adjacency between the second network device and the first network device, the adjacency being via the second logical link. determining, by an Intermediate System to Intermediate System, IS-IS, adjacency state machine executed by processing circuitry of a first network device (16, 40, 302) of a plurality of network devices (16, 40, 302) in a network comprising a dual-stack IS-IS network and operating in accordance with a link state routing protocol, that a first logical link (20A, 20B) according to a first networking protocol (52, 54) is active, wherein the first logical link is established on a first physical link (22, 304) between the first network device and a second network device (16, 40, 302) of the plurality of network devices; determining, by the adjacency state machine, that a second logical link (20A, 20B) according to a second networking protocol is active, wherein the second logical link is established on the first physical link between the first network device and the second network device, and wherein the first networking protocol and second networking protocol are different; in response to determining that both the first logical link and the second logical link are active, determining, by the adjacency state machine, that the second network device is adjacent to the first network device; and in response to determining that the second network device is adjacent to the first network device: outputting a first link state routing advertisement advertising the adjacency between the second network device and the first network device, the adjacency being via the first logical link; and outputting a second link state routing advertisement advertising the adjacency between the second network device and the first network device, the adjacency being via the second logical link. outputting a first link state routing advertisement advertising the adjacency between the second network device and the first network device, the adjacency being via the first logical link; and outputting a second link state routing advertisement advertising the adjacency between the second network device and the first network device, the adjacency being via the second logical link.