US 6,353,614 B1 · Method and protocol for distributed network address translation

Abstract

A method and protocol for Distributed Network Address Translation (“DNAT”) is provided. DNAT is used to overcome the limited address 32-bit address space used for versions of the Internet Protocol (“IP”). DNAT is used with small office or home office networks or other legacy local network that have multiple network devices using a common external network address to communicate with an external network. The protocol includes a port allocation protocol to allocate globally unique ports to network devices on a local computer network. The globally unique ports are used in a combination network address with a common external network address such as an IP address, to identify multiple network devices on a local network to an external network such as the Internet, an intranet, or a public switched telephone network. The method includes requesting one or more globally unique ports from network devices on a local network, receiving the ports, and replacing local ports with the globally unique ports. The network devices on the local network use the combination network address with the common external network address and the globally unique port to uniquely identify themselves during communications with an external network. DNAT overcomes the large computation burdens encountered when network address translation is done by a router for multiple network devices on a local network using a common external network address and simplifies routers since a router in a DNAT system does not have to support multiple individual protocols. DNAT helps extend the life of versions of IP using 32-bit addressing, allows a local network to efficiently switch between external network service providers and allows a local network to purchase a smaller block of external network addresses.

Claims42

Dependent claims

A computer readable medium having stored therein a set of routines for implementing a port allocation protocol, said protocol allowing a plurality of first network devices on a first network to use globally unique ports in combination with a common external network address to communicate with a plurality of second network devices on a second external network without network address translation, said set of routines implementing said protocol including a plurality of protocol messages and combination network addresses as data bits, the computer readable medium comprising:

a port allocation protocol request message, for requesting allocation of a plurality of globally unique port numbers for a network device;
a port allocation protocol response message, for receiving the plurality of globally unique port numbers for the network device;
a port allocation protocol invalidate message, for de-allocating the plurality of globally unique port numbers allocated to the network device;
and
a plurality of combination network addresses, having a globally unique port allocated by the port allocation protocol request message and a common external network address to identify a first network to a second external network, and allowing a plurality of first network devices on the first network to communicate with the plurality of second network devices on the second external network without network address translation.

2 more elements

A method of distributed network address translation, comprising the following steps:

requesting from a first network device on a first network with a first protocol, one or more globally unique ports from a second network device on the first network to identify the first network device during communications with a second external network;
receiving the one or more globally unique ports on the first network device from the second network device with the first protocol;
replacing a local port on the first network device with a globally unique port;
creating a combination network address for the first network device with the globally unique port and a common external network address to identify the first network device for communications with the second external network.

1 more element

A method of distributed network address translation, comprising the following steps:

requesting with a first protocol from a first network device on a first network, one or more globally unique ports from a second network device on the first network;
receiving the one or more globally unique ports on first network device from the second network device;
creating a request in a higher level protocol layer in a layered protocol stack on the first network device, for a third network device on a second external network, the request including a common network address and a local port on the first network device to identify the first network device on the first network to the second external network;
forwarding the request from the higher level protocol layer to a lower level protocol layer in the first network device;
translating the local port in the request to a globally unique port in the lower level protocol layer on the first network device;
sending the request from the first network device to the second network device;
and
forwarding the request from the second network device to the third network device on the second external network.

5 more elements

A method for distributed network address translation, comprising the following steps:

creating a request data packet on a first network device on a first network for a third network device on a second external network,
wherein the request data packet includes a data packet header with a common external network address to identify network devices on the first network to other network devices on the second external network and a globally unique port obtained from a second network device on the first network,
wherein the globally unique port uniquely identifies the first network device on the first network, and
wherein the globally unique port is used to replace a local source port on the first network device;
adding an additional request header to the request data packet to create a modified request data packet,
wherein the additional request header includes a first local internal network address for the first network device that identifies the first network device on the first network and a second local internal network address for the second network device that identifies the second network device on the first network;
and
forwarding the modified request data packet from the first network device to the second network device over the first network.

5 more elements

A method for distributed network address translation, comprising the following steps:

creating a request data packet on a first network device on a local network for a third network device on the Internet,
wherein the request data packet includes a data packet header with a common external Internet Protocol address to identify network devices on the local network to other network devices on the Internet and a globally unique port obtained from a router on the local network,
wherein the globally unique port uniquely identifies the first network device on the local network, and
wherein the globally unique port is used to replace a local source port on the first network device;
adding an additional request header to the request data packet to create a modified request data packet,
wherein the additional request header includes a first local internal Internet Protocol address for the first network device that identifies the first network device on the local network and a second local internal Internet Protocol address for the router that identifies the router on the local network;
and
forwarding the modified request data packet from the first network device to the router over the local network.

5 more elements

Dependencies are inferred from the claim text.

Method and protocol for distributed network address translation

Life of this patent

Method and protocol for distributed network address translation

Life of this patent

Abstract

Claims42