Method and system for routing data frames in a network topology

A method for routing data frames in a network topology comprising a plurality of routers and a plurality of nodes;

• the method comprising:
• a first router (R12 120) receiving from a first node (Node-A 121) a data frame including an Internet Protocol (IP) address of the first node (Node-A 121) in a source IP address field of the data frame, an IP address of a second node (Node-D 141) in a destination IP address field of the data frame, a Medium Access Control (MAC) address of the first node (Node-A 121) in a source MAC address field of the data frame, and in a destination MAC address field of the data frame a MAC address of an ingress interface of the first router (R12 120) obtained by the first node (Node-A 121) from the first router (R12 120);
• if the first router (R12 120) is a source router (R12 120), the source router (R12 120) replacing the source MAC address field in the data frame with a MAC address of an egress interface of the first router (R12 120), wherein the egress interface of the first router is indicated in an entry line of a routing table of the first router (R12 120) that matches with the destination IP address field in the received data frame;
• the first router (R12 120) determining, based on the IP address of the second node (Node-D 141), a MAC address of an ingress interface of a second router (R0 130), and replacing the destination MAC address field of the data frame with the MAC address of the ingress interface of the second router (R0 130);
• the first router (R12 120) sending the data frame to the second router (R0 130) through the egress interface of the first router (R12 120);
• if the second router (R0 130) is a transit router (R0 130), the transit router (R0 130) determining, based on the IP address of the second node (Node-D 141) indicated in the destination IP address field in the received data frame, a MAC address of an ingress interface of a third router (R34 140), and the second router (R0 130) replacing the destination MAC address field in the received data frame with the MAC address of the ingress interface of the third router (R34 140);
• the second router (R0 130) as the transit router (R0 130) setting/indicating the MAC address of the egress interface of the first router (R12 120) indicated in the source MAC address field of the data frame, in an entry line of a routing table of the transit router (R0 130) that matches with the source IP address field of the received data frame;
• the second router (R0 130) sending the data frame to the third router (R34 140) through an egress interface of the second router (R0 130) that matches with the destination IP address field of the received data frame;
• if the third router (R34 140) is the destination router (R34 140), the destination router (R34 140) replacing the destination MAC address of the received data frame with the MAC address of the second node (Node-D 141), and the source MAC address of the data frame with the MAC address of an egress interface of the third router (R34 140), wherein the egress interface of the third router (R34 140) is indicated in an entry line of a routing table of the third router (R34 140) that matches with the destination IP address field in the received data frame;
• the third router (R34 140) forwarding the data frame to the second node (Node-D 141) based on the destination MAC address indicated in the data frame;
• and the third router (R34 140) setting/indicating the MAC address of the egress interface of the first router (R12 120) indicated in the source MAC address field of the data frame, in an entry line of the routing table of the third router (R34 140) that matches with the source IP address field of the received data frame;
• the third router (R34 140) receiving a data frame from the second node (Node-D 141), the data frame including the IP address of the second node (Node-D 141) in a source IP address field of the data frame, the IP address of the first node (Node-A 121) in a destination IP address field of the data frame, a MAC address of the second node (Node-D 141) in a source MAC address field of the data frame, and a MAC address of the ingress interface of the third router (R34 140) in a destination MAC address field of the data frame;
• the third router (R34 140) replacing the source MAC address field of the data frame with a MAC address of an egress interface of the third router (R34 140), wherein the egress interface of the third router (R34 140) is indicated in an entry line of the routing table of the third router (R34 140) that matches with the destination IP address field in the received data frame;
• the third router (R34 140) retrieving from the routing table of the third router (R34 140), based on the IP address of the first node (Node-A 121), the MAC address of the interface of the first router (R12 120), and replacing the destination MAC address field of the data frame with the MAC address of the interface of the first router (R12 120);
• and
• the third router (R34 140) sending the data frame to the second router (R0 130) being a transit router through the egress interface of the third router (R34 140).