Methods and an apparatus for routing data packets in a network topology

A router in a visited network, for enabling routing of traffic at least one of to and from a roaming host node roaming from a subnet of a home network to the visited network, the home network having a plurality of host nodes, the roaming host node being assigned an Internet Protocol (IP) address in the home network, the router comprising a processor and a memory containing instructions executable by said router, the router being configured to:

• configure a subnet by assigning an IP address range to the subnet, the assigned IP address range being the same IP address range of the subnet of the home network;
• create or configure a tunnel between a router of the home network and the router of the visited network;
• the router of the home network being configured with a static route to point to the tunnel to route traffic from a host node of the plurality of host nodes located in the home network destined to the roaming host node located in the visited network, the roaming host node corresponding to a host node after it has roamed from the home network to the visited network, the traffic being routed through the tunnel and delivered to the roaming host node through a first connected interface to the visited network on the router of the visited network, and the IP address of the roaming host node being maintained unchanged in the subnet of the visited network;
• and
• configure the router of the visited network by applying a routing policy, the routing policy enabling the roaming host node located in the visited network to reply to received traffic from said host node located in the home network, the traffic received from the tunnel via said first interface and to route traffic from the roaming host node through a network interconnecting the router of the visited network and the router of the home network, and not through the tunnel.

A method in a router of a visited network, for enabling routing of traffic at least one of to and from a roaming host node roaming from a subnet of a home network to the visited network, the home network having a plurality of host nodes, the roaming host node being assigned an Internet Protocol (IP) address in the home network, the method comprising:

• configuring, in the router of the visited network to which the roaming host node is connected, a subnet by assigning an IP address range to the subnet, the assigned IP address range being the same IP address range of the subnet of the home network;
• creating or configuring a tunnel between a router of the home network and the router of the visited network, a static route to point to the tunnel being created or configured in the router of the visited network to route traffic from a host node of the plurality of host nodes located in the home network destined to the roaming host node located in the visited network, the roaming host node corresponding to a host node after it has roamed from the home network to the visited network, the traffic being routed through the tunnel and delivered to the roaming host node through a first connected interface to the visited network, on the router of the visited network, and the IP address of the roaming host node being maintained unchanged in the subnet of the visited network;
• and
• configuring the router of the visited network by applying a routing policy, the routing policy enabling the roaming host node located in the visited network to reply to received traffic from said host node located in the home network, the traffic received from the tunnel via said first interface and to route traffic from the roaming host node through a network interconnecting the router of the visited network and the router of the home network, and not through the tunnel.