A method implemented by a first Provider Edge, PE, network device in a network to configure a pseudo-wire, PW, between the first PE network device and a second PE network device in the network using Intermediate System to Intermediate System, IS-IS, the PE network devices being configured to provide one or more PWs on behalf of Customer Edge, CE, devices served so that the CE devices can communicate over a Packet-Switched Network, PSN, the method comprising: receiving a first link-state protocol data unit, LSP, update flooded in the network by the second PE network device via IS-IS, wherein the first LSP update includes a PW association type-length-value, TLV, targeted to the first PE network device, the PW association TLV including information about one or more PWs between a pair of endpoints and wherein the PW association TLV includes a PW sub-TLV that advertises the PW; determining whether the first PE network device supports the PW and whether the first PE network device has previously advertised the PW to the second PE network device; and in response to determining that the first PE network device supports the PW and has previously advertised the PW to the second PE network device: configuring a local forwarding information base with a local PW label associated with the PW such that the first PE network device forwards traffic encapsulated with the local PW label to an Attachment Circuit, AC, associated with the PW and flooding a second LSP update in the network via IS-IS, wherein the second LSP update includes an indication that the first PE network device is ready to receive traffic from the second PE network device over the PW. receiving a first link-state protocol data unit, LSP, update flooded in the network by the second PE network device via IS-IS, wherein the first LSP update includes a PW association type-length-value, TLV, targeted to the first PE network device, the PW association TLV including information about one or more PWs between a pair of endpoints and wherein the PW association TLV includes a PW sub-TLV that advertises the PW; determining whether the first PE network device supports the PW and whether the first PE network device has previously advertised the PW to the second PE network device; and in response to determining that the first PE network device supports the PW and has previously advertised the PW to the second PE network device: configuring a local forwarding information base with a local PW label associated with the PW such that the first PE network device forwards traffic encapsulated with the local PW label to an Attachment Circuit, AC, associated with the PW and flooding a second LSP update in the network via IS-IS, wherein the second LSP update includes an indication that the first PE network device is ready to receive traffic from the second PE network device over the PW. configuring a local forwarding information base with a local PW label associated with the PW such that the first PE network device forwards traffic encapsulated with the local PW label to an Attachment Circuit, AC, associated with the PW and flooding a second LSP update in the network via IS-IS, wherein the second LSP update includes an indication that the first PE network device is ready to receive traffic from the second PE network device over the PW.