ARP for Logical Router

• US 20150103842A1
• Filed: 12/20/2013
• Published: 04/16/2015
• Est. Priority Date: 10/13/2013
• Status: Active Grant

• Current Assignee: Nicira Incorporated (Broadcom, Inc.)
• Original Assignee: Nicira Incorporated (Broadcom, Inc.)
• Inventors: Chandrashekhar, Ganesan, Subramaniyam, Rahul Korivi, Singh, Ram Dular, Agarwal, Vivek, Wang, Howard
• Granted Patent: US 9,575,782 B2
• Time in Patent Office: Days
• US Class Current: 370/409
• CPC Class Codes: G06F 2009/45595 Network integration; Enabling network access in virtual machine instances
• CPC Class Codes: G06F 9/455 Emulation; Interpretation; Software simulation, e.g. virtualisation or emulation of application or operating system execution engines
• CPC Class Codes: G06F 9/45558 Hypervisor-specific management and integration aspects
• CPC Class Codes: H04L 45/44 Distributed routing
• CPC Class Codes: H04L 45/586 of virtual routers
• CPC Class Codes: H04L 45/741 Routing in networks with a plurality of addressing schemes, e.g. with both IPv4 and IPv6
• CPC Class Codes: H04L 61/103 across network layers, e.g. resolution of network layer into physical layer addresses or address resolution protocol [ARP]

Abstract

Some embodiments provide a method for a computing device serving as a host machine in a logical network. The method executes several virtual machines that are in several different segments of the logical network. The method operates a managed physical routing element (MPRE) for routing data packets between different segments of the logical network. The MPRE includes several logical interfaces, each of which is for receiving data packets from a different segment of the logical network. Each of the logical interfaces is addressable by a network layer address. The method intercepts an Address Resolution Protocol (ARP) broadcast message when the destination address matches the network address of one of the logical interfaces. The method formulates an ARP reply to the ARP broadcast message.

Claims

1. A computing device serving as a host machine in a logical network, the computing device executing a computer program comprising sets of instructions for:

executing a plurality of virtual machines that are in a plurality of different segments of the logical network;

operating a managed physical routing element (MPRE) for routing data packets between different segments of the logical network, the MPRE comprising a plurality of logical interfaces, each logical interface for receiving data packets from a different segment of the logical network, wherein each of the logical interfaces is addressable by a network layer address;

intercepting an Address Resolution Protocol (ARP) broadcast message when the destination address matches the network address of one of the logical interfaces; and

formulating an ARP reply to the ARP broadcast message.

2. The computing device of claim 1, wherein the ARP broadcast message is sent by a virtual machine operating in the host machine.

3. The computing device of claim 1, wherein the ARP broadcast message comprises a broadcast media access control (MAC) address, the method further comprising replacing the broadcast MAC address with a virtual MAC (VMAC) address for the MPRE.

4. The computing device of claim 1, wherein the source MAC address of the ARP reply is set to a virtual MAC (VMAC) address for the MPRE, wherein the VMAC is common to all host machines in the logical network.

5. The computing device of claim 1, wherein at least one of the segments of the logical network is an overlay encapsulation network.

6. A computing device serving as a host machine in a logical network, the computing device executing a computer program comprising sets of instructions for:

executing a plurality of virtual machines that are in a plurality of different segments of the logical network;

operating a first managed physical routing element (MPRE) for routing data packets between different segments of the logical network;

intercepting an Address Resolution Protocol (ARP) broadcast message that is sent by a second MPRE operating in another host machine of the logical network; and

formulating an ARP reply to the ARP broadcast message.

7. The computing device of claim 6, wherein the ARP broadcast message comprises a physical MAC (PMAC) address that uniquely identifies the second MPRE of the other host machine.

8. The computing device of claim 7, wherein formulating the ARP reply message comprises setting the destination address to the PMAC that uniquely identifies the MPRE of the other host machine that sent the ARP broadcast message.

9. The computing device of claim 6, wherein the ARP broadcast message is a first ARP broadcast message, the method further comprising sending a second ARP broadcast message to the virtual machines operating in the host machine when the MPRE is not able to resolve a network layer address in the first ARP broadcast message.

10. A system comprising:

a plurality of host machines for hosting a plurality of virtual machines in a logical network, each host machine operating a managed physical routing element (MPRE) for routing data packet between virtual machines that are in different segments of the logical network; and

a physical host machine that does not host a virtual machine in the logical network, wherein a particular MPRE in a particular host machine is selected for performing network layer routing on data packets from the physical host machine to the virtual machines being hosted by the plurality of host machines.

11. The system of claim 10, wherein data packets from the physical host machine to host machines other than the particular host machine are routed by the selected MPRE.

12. The system of claim 11, wherein data packets from the other host machines to the physical host machine are not routed by the selected MPRE.

13. The system of claim 12, wherein a host machine that is not the particular host machine request address resolution information for the physical host from the particular host machine.

14. The system of claim 10, wherein data packets from the physical host machine to the plurality of host machines use a unique physical media access control (PMAC) address associated with the selected router as a destination address.

15. The system of claim 14, wherein each host machine in the plurality of host machines replace the PMAC of the selected router with a virtual MAC (VMAC) address before routing, wherein the VMAC is generic to the MPREs in the plurality of host machines.

16. The system of claim 14, wherein data packets from each host machine to the physical host machine use each host machine'"'"'s own unique PMAC address as a source address.

17. A system comprising:

a plurality of host machines for hosting a plurality of virtual machines in a logical network, each host machine operating a managed physical routing element (MPRE) for routing data packets between virtual machines that are in different segments of the logical network; and

a physical host machine that does not host a virtual machine in the logical network, wherein a particular MPRE in a particular host machine is selected for responding to an address resolution protocol (ARP) message sent by the physical host machine.

18. The system of claim 17, wherein the response to the ARP message from the selected MPRE comprises a unique physical media access control (PMAC) address of the host machine that operates the selected MPRE.

19. The system of claim 18, wherein host machines other than the particular host machine operating the selected MPRE do not respond to the ARP message.

20. The system of claim 17, wherein the particular host machine stores address resolution information about the physical host machine based on the ARP message and provides the address resolution information about the physical host machine to other host machines.