# US 12,192,103 B2 · Intermediate logical interfaces in a virtual distributed router environment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,192,103 B2 - Document ID: US12192103B2 - Status: Granted - Kind: B2 - Application number: 18/241,234 - Filed: 2023-09-01 - Published: 2023-12-28 - Granted: 2025-01-07 - Earliest claimed: 2015-06-30 - Assignees: Nicira, Inc. - Applicants: Nicira, Inc. - Inventors: Vivek Agarwal; Ganesan Chandrashekhar; Rahul Korivi Subramaniyam; Howard Wang; Ram Dular Singh - Web page: https://patentgrep.com/patent/US12192103B2 ## CPC - G06F 9/45558: {Hypervisor-specific management and integration aspects} - H04L 12/4641: {Virtual LANs, VLANs, e.g. virtual private networks [VPN] (LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272)} - H04L 45/04: {Interdomain routing, e.g. hierarchical routing} - H04L 45/38: {Flow based routing} - H04L 45/44: Distributed routing - H04L 45/586: of virtual routers - H04L 45/66: {Layer 2 routing, e.g. in Ethernet based MAN's} - H04L 45/74: Address processing for routing - H04L 47/33: using forward notification - H04L 69/325: in the network layer [OSI layer 3], e.g. X.25 (H04L69/16 takes precedence) - G06F 2009/45595: {Network integration; Enabling network access in virtual machine instances} - H04L 41/0895: Configuration of virtualised networks or elements, e.g. virtualised network function or OpenFlow elements - H04L 49/70: {Virtual switches} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A LRE (logical routing element) that have LIFs that are active in all host machines spanned by the LRE as well as LIFs that are active in only a subset of those spanned host machines is provided. A host machine having an active LIF for a particular L2 segment would perform the L3 routing operations for network traffic related to that L2 segment. A host machine having an inactive LIF for the particular L2 segment would not perform L3 routing operations for the network traffic of the L2 segment. ## Claims ### Claim 1 A method of forwarding packets from a logical network to an external network through an edge gateway, the method comprising: at a first host computer: receiving a packet at a first router that executes on the first host computer to implement a logical router for the logical network along with a plurality of other routers executing on a plurality of other host computers; performing a routing lookup to determine that the packet is directed to an interface that is not active on the first host computer but is active on a second host computer on which the edge gateway executes; using a logical switch implemented by the first and second host computers to forward the packet to the second host computer for the packet to be processed by the gateway and forwarded to the external network. ### Claim 2 (depends on 1) The method of claim 1, wherein the interface is a logical interface (LIF). ### Claim 3 (depends on 2) The method of claim 2, wherein the LIF is only active on any host computer that executes an edge gateway connecting the logical network to another network. ### Claim 4 (depends on 2) The method of claim 2, wherein the LIF is associated with the logical router. ### Claim 5 (depends on 4) The method of claim 4, wherein the packet is a first packet and the interface is a first interface, the method further comprising: at a first host computer: receiving a second packet at the first router; performing a routing lookup to determine that the packet is directed to a second interface that is active on the first host computer; forwarding the second packet through the second interface to reach a destination of the second packet in the logical network. ### Claim 6 (depends on 5) The method of claim 5 further comprising: identifying a layer 2 (L2) destination address for second packet by using the destination IP address of the second packet; providing the second packet with the identified L2 destination address to a switch to forward the packet to the second packet's destination in the logical network. ### Claim 7 (depends on 1) The method of claim 1 further comprising assigning to the packet a media access control (MAC) address that is used to identify the interface of the logical switch on the second hot computer. ### Claim 8 (depends on 7) The method of claim 7, wherein the MAC is an rMAC when the only edge gateway is the edge gateway executing on the second host computer or is an IMAC associated with the second host computer when more than one edge gateways execute on more than one host computers. ### Claim 9 (depends on 1) The method of claim 1, wherein the external network is a virtual local area network (VLAN). ### Claim 10 (depends on 9) The method of claim 9, wherein the logical network is an overlay logical network that is established by encapsulating packets sent between the host computers with encapsulation headers that store overlay logical network data. ### Claim 11 A non-transitory machine readable medium storing a program for execution by at least one processing unit of a first host computer to forward packets from a logical network to an external network through an edge gateway, the program comprising sets of instructions for: receiving a packet at a first router that executes on the first host computer to implement a logical router for the logical network along with a plurality of other routers executing on a plurality of other host computers; performing a routing lookup to determine that the packet is directed to an interface that is not active on the first host computer but is active on a second host computer on which the edge gateway executes; using a logical switch implemented by the first and second host computers to forward the packet to the second host computer for the packet to be processed by the gateway and forwarded to the external network. ### Claim 12 (depends on 11) The non-transitory machine readable medium of claim 11, wherein the interface is a logical interface (LIF). ### Claim 13 (depends on 12) The non-transitory machine readable medium of claim 12, wherein the LIF is only active on any host computer that executes an edge gateway connecting the logical network to another network. ### Claim 14 (depends on 12) The non-transitory machine readable medium of claim 12, wherein the LIF is associated with the logical router. ### Claim 15 (depends on 14) The non-transitory machine readable medium of claim 14, wherein the packet is a first packet and the interface is a first interface, the program further comprising sets of instructions for: receiving a second packet at the first router; performing a routing lookup to determine that the packet is directed to a second interface that is active on the first host computer; forwarding the second packet through the second interface to reach a destination of the second packet in the logical network. ### Claim 16 (depends on 15) The non-transitory machine readable medium of claim 15, wherein the program further comprises sets of instructions for: identifying a layer 2 (L2) destination address for second packet by using the destination IP address of the second packet; providing the second packet with the identified L2 destination address to a switch to forward the packet to the second packet's destination in the logical network. ### Claim 17 (depends on 11) The non-transitory machine readable medium of claim 11, wherein the program further comprises a set of instructions for assigning to the packet a media access control (MAC) address that is used to identify the interface of the logical switch on the second hot computer. ### Claim 18 (depends on 17) The non-transitory machine readable medium of claim 17, wherein the MAC is an rMAC when the only edge gateway is the edge gateway executing on the second host computer or is an IMAC associated with the second host computer when more than one edge gateways execute on more than one host computers. ### Claim 19 (depends on 11) The non-transitory machine readable medium of claim 11, wherein the external network is a virtual local area network (VLAN). ### Claim 20 (depends on 19) The non-transitory machine readable medium of claim 19, wherein the logical network is an overlay logical network that is established by encapsulating packets sent between the host computers with encapsulation headers that store overlay logical network data.