# US 11,121,969 B2 · Routing between software defined networks and physical networks

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- Number: US 11,121,969 B2
- Document ID: US11121969B2
- Status: Granted
- Kind: B2
- Application number: 16/688,064
- Filed: 2019-11-19
- Published: 2020-03-12
- Granted: 2021-09-14
- Earliest claimed: 2017-11-09
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Gang Tang; Shi Xin Ruan; Zhu Na; Ming Shuang Xian
- Web page: https://patentgrep.com/patent/US11121969B2

## CPC

- H04L 45/38: {Flow based routing}
- H04L 12/66: Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
- H04L 45/66: {Layer 2 routing, e.g. in Ethernet based MAN's}
- H04L 45/745: Address table lookup; Address filtering
- H04L 12/4633: {Interconnection of networks using encapsulation techniques, e.g. tunneling}
- H04L 45/586: of virtual routers
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A method includes receiving, at a data link layer (layer 2) gateway device configured to connect the physical network to the SDN network, routing data to a computing device, the computing device selected to receive a packet transmitted from the physical network to the SDN network; receiving, from a source element in the physical network, an address request for a layer 2 address of a router element in the SDN network, the address request including a networking layer address of the router element; transmitting, to the source element in response to receiving the address request, a layer 2 address of the router element using the routing data; receiving, from the source element, a routing request to route a packet to a destination element in the SDN network using the layer 2 address; routing, using the routing data, the received packet to the computing device to route to the destination element.

## Claims

### Claim 1

A system comprising:
a software defined networking network (SDN network) comprising node element and router element, the router element having components executing on two or more computing devices;
a physical network comprising physical network elements;
a controller to control a flow network information through the SDN network; and
a data link layer (layer 2) gateway device configured to:
receive, from the controller, routing data to a computing device of the two or more computing devices, the computing device selected to receive a packet transmitted from the physical network to the SDN network;
receive, from a first element of the physical network elements, an address request for a layer 2 address of a router element in the SDN network, the address request including a networking layer address of the router element;
transmit, to the first element in response to receiving the request for the data link layer address, the layer 2 address of the router element using the routing data;
receive, from the first element, a routing request to route the packet to a destination element in the SDN network using the layer 2 address; and
route the received packet to the selected computing device.

### Claim 2 (depends on 1)

The system of claim 1, wherein the router element and the node element are connected between distinct computing devices using a network tunnel, and the layer 2 gateway device is further configured to:
determine, based on the layer 2 address, header information for routing the received packet through the network tunnel to a component of the router element executing on the selected computing device; and
encapsulate the received packet in the header information.

### Claim 3 (depends on 1)

The system of claim 1, wherein the controller is configured to:
store routing data indicating a network interface on the router element to receive the packet transmitted from the node element to the first element.

### Claim 4 (depends on 1)

The system of claim 1, wherein the physical network stores routing information indicating a network interface on the router element to receive the packet transmitted from the first element to the node element.

### Claim 5 (depends on 1)

The system of claim 1, wherein the router element comprises components executing on each computing device of the two or more computing devices.

### Claim 6 (depends on 1)

The system of claim 1, wherein the SDN network is mapped to a second element of the physical network elements through a network tunnel.

### Claim 7 (depends on 1)

The system of claim 1, wherein the SDN network comprises two or more SDN sub networks, and at least one of the two or more SDN sub networks comprise at least a second element of the physical network elements.

### Claim 8 (depends on 1)

The system of claim 1, wherein the controller is configured to a computing device to receive a packet transmitted to the SDN network in response to determining that the computing device has a greater capacity to process the transmitted packet than other available computing devices.

### Claim 9 (depends on 1)

The system of claim 1, wherein the router element is a distributed logical router.