Method of creating address forwarding table in ethernet ring network
Provided is a method of creating an address forwarding table in an Ethernet ring network. The method includes the steps of: broadcasting, at each Ethernet node, a ring learning frame having information for measuring cost in the frame's payload in both directions; and receiving, at each Ethernet node, two ring learning frames transferred from different Ethernet nodes and recording a ring learning frame containing information having the minimum cost in the Ethernet node's address forwarding table. Accordingly, by creating an intelligent address forwarding table, it is possible to efficiently prevent a loop without conventionally using a closed loop, and to rapidly transfer a frame through an optimal path.
1 . A method of creating an address forwarding table in an Ethernet ring network in which a plurality of Ethernet nodes are connected in a ring shape, the method comprising the steps of:
broadcasting, at each Ethernet node, a ring learning frame having information for measuring cost in a payload in both directions; and
receiving, at each Ethernet node, two ring learning frames transferred from different Ethernet nodes and recording a ring learning frame containing information having the minimum cost in the Ethernet node's address forwarding table.
2 . The method of claim 1 , wherein each Ethernet node receiving the ring learning frame searches for a source address of the received ring learning frame in the Ethernet node's address forwarding table, and when the source address does not exist in the address forwarding table, records a port and the source address of the received ring learning frame in the address forwarding table and records a cost value included in the payload of the ring learning frame in the Ethernet node's cost table.
3 . The method of claim 1 or 2 , wherein each Ethernet node receiving the ring learning frame searches for the source address of the received ring learning frame in the Ethernet node's address forwarding table, compares a cost value included in the payload of the ring learning frame with a cost value recorded in the Ethernet node's cost table when the source address exists in the address forwarding table, deletes the source address and the cost value respectively recorded in the Ethernet node's address forwarding table and cost table, and records the source address and the cost value of the received ring learning frame when the cost value included in the payload of the ring learning frame is smaller than the cost value recorded in the Ethernet node's cost table.
4 . The method of claim 1 , wherein the information for measuring cost includes information on time and a number of hops.
5 . A method of creating an address forwarding table in an Ethernet ring network in which a plurality of Ethernet nodes comprising a subnetwork comprised of a large number of Ethernet stations are connected in a ring shape, the method comprising the step of:
when a destination address of a frame transferred from a subnetwork of one Ethernet node exists in an address forwarding table of each Ethernet node, but a source address does not exist, recording, at each Ethernet node, the source address as a new entry in the Ethernet node's address forwarding table and transferring the frame through a port corresponding to the destination address recorded in the Ethernet node's address forwarding table so that the frame is transferred to a subnetwork of an Ethernet node having the destination address.
6 . A method of creating an address forwarding table in an Ethernet ring network in which a plurality of Ethernet nodes comprising a subnetwork comprised of a large number of Ethernet stations are connected in a ring shape, the method comprising the steps of:
when a destination address of a frame transferred from a subnetwork of one Ethernet node exists in some address forwarding tables of the Ethernet nodes, recording and encapsulating, at an Ethernet node whose address forwarding table does not have the destination address, an address of the corresponding Ethernet node as a source address of the transferred frame and multicasting as a destination address in the transferred frame, and then transferring the encapsulated frame through one port;
decapsulating, at an Ethernet node receiving the encapsulated frame, the encapsulated frame, checking the destination address, and when the destination address of the initial frame does not exist in the corresponding Ethernet node's address forwarding table, broadcasting the frame to a subnetwork connected with the corresponding Ethernet node and re-encapsulating and transferring the frame to a next node; and
after decapsulating and transferring, at an Ethernet node whose address forwarding table has the destination address, the encapsulated frame to a subnetwork corresponding to the destination address, generating, at the subnetwork having the destination address, a new Media Access Control (MAC) learning frame in which the destination address is recorded as a source address, and the address of the initial Ethernet node recorded as the source address of the encapsulated frame is recorded as a destination address, and transferring the MAC learning frame in a direction of a port recorded in the Ethernet node's address forwarding table so that the MAC learning frame reaches the subnetwork having the destination address.
7 . A method of creating an address forwarding table in an Ethernet ring network in which a plurality of Ethernet nodes comprising a subnetwork including a large number of Ethernet stations are connected in a ring shape, the method comprising the steps of:
when a destination address of a frame transferred from a subnetwork of one initial Ethernet node does not exist in an address forwarding table of each Ethernet node, recording and encapsulating, at each Ethernet node, an address of the initial Ethernet node as a source address and multicasting as a destination address in the transferred frame, and then transferring the encapsulated frame through one port;
decapsulating, at an Ethernet node receiving the encapsulated frame, the encapsulated frame, checking the destination address, and when the destination address of the initial frame does not exist in an address forwarding table of the Ethernet node, broadcasting the frame to a subnetwork connected with the Ethernet node and re-encapsulating and transferring the frame to a next node; and
when the frame is transferred to the initial Ethernet node corresponding to the source address, discarding and terminating, at the initial Ethernet node, the transferred frame.
8 . A recording medium storing a computer program for executing the above-described method of any one of claims 1 to 7 .