Efficient address-space extension to pseudo multi-homed hosts

A method for preparing, on a first network, a packet for communication, comprising the steps of:

• determining whether a destination address is within the first network (S320);
• if it is determined that the address is not within the first network, providing the packet with a source address that is one of addresses from a second network used by a gateway connecting the first and second networks (S360);
• and
• if it is determined that the address is within the first network, providing the packet with a source address within the first network (S330).

A device for preparing, on a first network, a packet for communication, said device being configured for:

• determining whether a destination address is within the first network (S320);
• if it is determined that the address is not within the first network, providing the packet with a source address that is one of addresses from a second network used by a gateway connecting the first and second networks (S360);
• and
• if it is determined that the address is within the first network, providing the packet with a source address within the first network (S330).

A method for routing information, the method comprising the steps of:

• receiving, in a first network from a second network, the first and second networks being different address realms, a packet that specifies a location of a device within said first network (710), said device having an address of lower level than an Internet address;
• and,
• without modifying the received packet as to any address within the received packet:
• generating, from the received packet, an address corresponding to said location (720);
• deriving the lower-level address from the generated address (730);
• encapsulating the received packet so as to thereby add the derived lower-level address and form an encapsulated packet;
• and
• transmitting said encapsulated packet to the specified location (740).

A method for routing information from a first network to a second network, the first and second networks being different address realms, the method comprising the steps of:

• deriving from an Internet Protocol (IP) address an address of lower level (S370);
• creating, by a first device in said first network, a packet specifying as a destination a second device within said second network (504, 516);
• without modifying the created packet as to any address within the created packet, encapsulating said created packet so as to thereby add the derived address and form an encapsulated packet;
• forwarding the encapsulated packet to another device in the first network (S380);
• and
• without modifying the forwarded packet as to any address within the forwarded packet, stripping off the encapsulation to leave the created packet and transmitting the left packet to said destination.