A convergence method of an End Station Address Distribution Information, ESADI, protocol, the method comprises: computing a unicast encapsulation table through a Transparent Interconnection over Lots of Links, TRILL, protocol, when network topology is changed, wherein the unicast encapsulation table is used to determine the reachability of all Routing Bridges, RBs, as appointed remote Virtual Local Area Network, VLAN, forwarders; establishing, in a local VLAN a neighbouring relationship between a local Routing Bridge, RB, and a remote RB to achieve fast convergence of the ESADI protocol, when the unicast encapsulation table includes the remote RB as an appointed remote VLAN forwarder which is reachable, and the local RB has received a Link-State Packet, LSP, for enabling ESADI function information from the remote RB, wherein the unicast encapsulation table including the remote RB as an appointed remote VLAN forwarder which is reachable comprises: when an encapsulation table term of the remote VLAN of the remote RB exists in the local RB, the remote RB as the appointed remote VLAN forwarder is reachable, wherein the establishing, in a local VLAN, a neighbouring relationship between a local RB and a remote RB, comprises: when the local RB has received the LSP from the remote RB, and the unicast encapsulation table comprises the encapsulation table term of the remote VLAN of the remote RB, adding the remote RB to be an ESADI neighbouring RB and issuing a Media Access Control, MAC, table term indicating the remote RB is reachable, by the local VLAN; otherwise, not adding the remote RB to be an ESADI neighbouring RB or issuing a MAC table term indicating the remote RB is reachable, by the local VLAN. computing a unicast encapsulation table through a Transparent Interconnection over Lots of Links, TRILL, protocol, when network topology is changed, wherein the unicast encapsulation table is used to determine the reachability of all Routing Bridges, RBs, as appointed remote Virtual Local Area Network, VLAN, forwarders; establishing, in a local VLAN a neighbouring relationship between a local Routing Bridge, RB, and a remote RB to achieve fast convergence of the ESADI protocol, when the unicast encapsulation table includes the remote RB as an appointed remote VLAN forwarder which is reachable, and the local RB has received a Link-State Packet, LSP, for enabling ESADI function information from the remote RB, wherein the unicast encapsulation table including the remote RB as an appointed remote VLAN forwarder which is reachable comprises: when an encapsulation table term of the remote VLAN of the remote RB exists in the local RB, the remote RB as the appointed remote VLAN forwarder is reachable, wherein the establishing, in a local VLAN, a neighbouring relationship between a local RB and a remote RB, comprises: when the local RB has received the LSP from the remote RB, and the unicast encapsulation table comprises the encapsulation table term of the remote VLAN of the remote RB, adding the remote RB to be an ESADI neighbouring RB and issuing a Media Access Control, MAC, table term indicating the remote RB is reachable, by the local VLAN; otherwise, not adding the remote RB to be an ESADI neighbouring RB or issuing a MAC table term indicating the remote RB is reachable, by the local VLAN. when an encapsulation table term of the remote VLAN of the remote RB exists in the local RB, the remote RB as the appointed remote VLAN forwarder is reachable, wherein the establishing, in a local VLAN, a neighbouring relationship between a local RB and a remote RB, comprises: when the local RB has received the LSP from the remote RB, and the unicast encapsulation table comprises the encapsulation table term of the remote VLAN of the remote RB, adding the remote RB to be an ESADI neighbouring RB and issuing a Media Access Control, MAC, table term indicating the remote RB is reachable, by the local VLAN; otherwise, not adding the remote RB to be an ESADI neighbouring RB or issuing a MAC table term indicating the remote RB is reachable, by the local VLAN.